Dụng Cụ Chỉnh Hình Và Chân Tay Giả Trong Phục Hồi Chức Năng (Ấn Bản Thứ 3)

142
Section I  Building Baseline Knowledge
132. Zahedi MS, Spence WD, Solomonidis SE, et al. Alignment of
lower-limb prostheses. J Rehabil Res Dev. 1986;23(2):2–19.
133. Goh JCH, Solomonidis SE, Spence WD, et al. Biomechanical
evaluation of SACH and uniaxial feet. Prosthet Orthot Int.
1984;8(3):147–154.
134. Doane NE, Holt LE. A comparison of the SACH and single
axis foot in the gait of unilateral below-knee amputees. Prosthet
Orthot Int. 1983;7:33–36.
135. Culham EG, Peat M, Nowell E. Below-knee amputation:
A comparison of the effects of the SACH foot and the single
axis foot on electromyographic patterns during locomotion.
Prosthet Orthot Int. 1986;10(1):15–22.
136. Burgess EM, Hittenberger DA, Forsgren SM, et al. The Seattle
prosthetic foot—a design for active sports: preliminary studies.
Orthot Prosthet. 1983;37(1):25–31.
137. Waters RL, Antonelli D, Hislop H. Energy cost of walking of
amputees: the influence of level of amputation. J Bone Joint
Surg. 1976;58(1):42–46.
138. Wagner EM, Sienko S, Supan T, et al. Motion analysis of SACH
vs. Flexfoot in moderately active below-knee amputees. Clin
Prosthet Orthot. 1987;11:55–62.
139. Torburn L, Perry J, Ayyappa E. Below knee amputee gait with
dynamic elastic response prosthetic feet: a pilot study. J Rehabil
Res Dev. 1990;27(4):369–384.
140. Barth D, Schumacher L, Sienko TS. Gait analysis and energy
cost of below-knee amputees wearing six different prosthetic
feet. J Prosthet Orthot. 1992;4(2):63–75.
141. Gitter A, Czerniecki JM, DeGroot DM. Biomechanical analy­
sis of the influence of prosthetic feet on below-knee amputee
walking. Am J Phys Med Rehabil. 1990;70:142–148.
142. Powers CM, Torburn L, Perry J, et  al. Influence of pros­
thetic foot design on sound limb loading in adults with uni­
lateral below-knee amputations. Arch Phys Med Rehabil.
1994;75:825–829.
143. Farivar S, Ayyappa E. Time-distance parameters of trans-femoral
amputees. Proceedings of the 23rd Annual Meeting and Scientific
Symposium, American Academy of Orthotists and Prosthetists.
1996 Orlando.
144. James U, Oberg K. Prosthetic gait patterns in unilateral above-
knee amputees. Scand J Rehabil Med. 1973;5(1):35–50.
145. Murray MP, Mollinger LA, Sepic SB, et  al. Gait patterns in
above-knee amputee patients: hydraulic swing control vs.
constant-friction knee components. Arch Phys Med Rehabil.
1983;64(8):339–345.
146. Suzuki K. Force plate study on artificial limb gait. J Jap Orthop
Assoc. 1972;46:503–516.
147. Thiele B, James U, Stalberg E. Neurophysiological studies on
muscle function in the stump of transfemoral amputees. Scand
J Rehabil Med. 1983;l5:67–70.
148. Zuniga EN, Leavitt LA, Calvert JC, et  al. Gait patterns in
trans-femoral amputees. Arch Phys Med Rehabil. 1972;53:
373–382.
149. Ayyappa E. Gait and Limb Technology: Microprocessor Knees,
Capabilities. vol. II, no 2. Chicago: Northwestern University;
2002.
150. Kaufman K. Instrumented Comparison Between Mauch SNS
Hydraulic Knee and the Otto Bock C-Leg. In: Proceedings of
4th Annual National VA Conference on Prosthetic & Orthotic
Rehabilitation. Long Beach, CA; 2004.
151. Murray MP, Sepic SB, Gardner GM, et  al. Gait patterns of
Trans-Femoral amputees using constant-friction knee compo­
nents. Bull Prosthet Res. 1980;13(2):35–45.
152. Evaluation of Gait of Unilateral AK Individuals with Amputation.
New York: NYU College of Engineering; 1951.

143
Materials and Technology
Géza F. Kogler
A fundamental concept and common goal within the professions
of orthotics, prosthetics, and rehabilitation is the restoration of
normal form and function after injury or disease. To accept this
challenge, the fields of orthotics and prosthetics have evolved
into uniquely specialized professions. In addition to training in
the basic biological and medical sciences, orthotists and prosthe­
tists have an understanding of biomechanics, kinesiology, and
the material sciences complemented by highly developed tech­
nical skills. Knowledge of the physical properties of materials
and the techniques to manipulate and use them is essential to
the design and fabrication of orthoses and prostheses. The topic
is presented here as a general overview so that the rehabilitation
clinician can develop a basic understanding of current design
and fabrication processes used by orthotists and prosthetists.
ORTHOTICS AND PROSTHETICS IN THE
TWENTIETH CENTURY
Orthotics and prosthetics have a rich history of research and
development. Many innovative devices have been designed
to restore function and provide relief from various medical
ailments. Although progress can be documented throughout
human history, the most significant contributions to orthot­
ics and prosthetics were made in the twentieth century, stim­
ulated by the aftermath of the world wars. Injured veterans
who returned home from battle with musculoskeletal and
neuromuscular impairments or traumatic amputation dra­
matically increased the demand for orthotic and prosthetic
services. Although World War I stimulated some clinical
progress in the two disciplines, notable scientific advance­
ments did not occur until World War II. To improve the qual­
ity and performance of assistive devices at the end of World
War II, particularly for veterans with amputation, the U.S.
government sponsored a series of research and develop­
ment projects under the auspices of the National Academy
of Sciences (NAS) that would forever change the manner in
which orthotics and prosthetics would be practiced.1
An extensive research effort was initiated by the NAS in late
1945, when a consensus conference revealed that few modern
scientific principles or developments had been introduced
in prosthetics.2 Research and educational committees were
formed between 1945 and 1976 to advise and work with the
research groups. Universities, the Veterans Administration,
private industry, and other military research units were sub­
contracted to conduct various prosthetic research projects. In
summarizing the most notable achievements in prosthetics
during this period, Wilson3 cites the development of the total
contact transfemoral socket; the quadrilateral socket design
and hydraulic swing-phase knee-control units for the trans­
femoral prosthesis; the patellar tendon-bearing (PTB) trans­
tibial prosthesis; the solid-ankle, cushioned-heel prosthetic
foot; several new designs for the Syme's prosthesis; and the
Canadian hip-disarticulation prosthesis. He also notes the
implementation of immediate postsurgical and early fitting
as having a significant impact on the rehabilitation process
for persons with lower extremity amputation. The most nota­
ble improvements in upper extremity prosthetics were the
lyre-shaped three-jaw chuck terminal device and more effi­
cient harnessing systems. In addition, modular components
and advances in bioengineering have permitted increased use
and availability of the myoelectric prosthesis since it was first
­proposed in 1950.4
Of the wealth of scientific advances made during this inten­
sive research period, the most important is the greater atten­
tion paid to the biomechanics of prosthetic alignment and
6
LEARNING OBJECTIVES
On completion of this chapter, the reader will be able to:
1. Compare and contrast the materials most often used in
current orthoses and prostheses.
2. Describe how the basic mechanical properties of ­commonly
used materials determine how they will be used in orthotic
and prosthetic devices.
3. Describe the process of, and measures used in, the formula­
tion of a biomechanically appropriate orthotic or prosthetic
prescription that will address a patient's functional deficits.
4. Describe how a prosthetist or orthotist determines the appro­
priate prosthetic or orthotic controls needed for the manage­
ment of a patient's impairments or functional limitations.
5. Delineate the steps in the fabrication or production of a
custom orthosis or prosthesis.
6. Discuss the use of computer-aided design/computer-aided
manufacture (CAD/CAM) in the measurement for and
fabrication of orthoses and prostheses.
7. Describe the factors influencing the development of central
fabrication centers and the manufacture of prefabricated
components, orthoses, and prostheses.

144
Section I  Building Baseline Knowledge
socket design.5 According to Wilson,2 “The introduction of
socket designs based on sound biomechanical analyses to take
full advantage of the functions and properties of the stump
in conjunction with the rationale for alignment undoubt­
edly represents the greatest achievement in prosthetics
since World War II.”
Although the focus of the NAS Artificial Limb Program
was in prosthetics, it was anticipated that these efforts would
also benefit orthotics. A formal research directive in orthot­
ics did not begin until 1960. Biomechanical principles devel­
oped for the PTB prosthesis were immediately introduced in
orthotics at the Veterans Administration Prosthetic Center,
with the PTB orthosis to unload the foot-ankle complex
­axially.6 The concept of fracture bracing or cast bracing began
at approximately the same time and is now common practice
for orthopedic management of fractures.7,8 Clinical aspects of
orthotic practice were also considered; a systematic approach
to prescription formulation was established with the devel­
opment of the technical analysis forms. Nomenclature to
describe orthoses and their functions was standardized
to identify the body segments they encompassed with the
desired biomechanical control mechanisms.9
The introduction of new materials led to further advances
in the field shortly after World War II. The use of thermo­
setting plastics in prosthetics permitted the development of
the suction socket suspension system.10 Transparent plastics
offered a new approach to diagnostic and fitting evaluation
techniques, such as the transparent prosthetic socket (test
socket) and the transparent face mask for patients with ther­
mal injuries. In orthotics, the addition of thermoplastics led to
numerous innovative designs of ankle-foot orthoses (AFOs)
in the 1960s and 1970s. The custom plastic AFO was an
important technological advance in lower extremity orthot­
ics. The physical characteristics of thermoformable plastics
allowed biomechanical controls to match the prescription for
improved function. The mechanical properties of an orthosis
could be controlled by the layout of the trimlines of a device
or structural reinforcements through specially placed corru­
gations that could be incorporated into its surface geometry.
Advances have been steady in the area of material engineer­
ing and continue to have an impact on orthotics and pros­
thetics. Numerous prosthetic feet have been introduced as
elite athletes demand increased performance capabilities from
their prosthetic components. Innovative designs for some
prosthetic feet have been possible in part because of the diver­
sity of carbon composite technology complemented by sound
engineering design.
The development of computer-aided design/computer-
aided manufacture (CAD/CAM) systems for orthotics and
prosthetics, which began in the 1970s, was another major
technological advance, considering the long tradition of cus­
tom hand-crafted devices in the profession. In the late 1980s
and early 1990s, as computers became more economical, facil­
ities began to integrate CAD/CAM systems into their prac­
tices. CAD/CAM systems have now been designed for most
orthotic and prosthetic applications, often with specialized
digitizers, scanners, and milling equipment to accommodate
the unique needs of a particular device. The current trend
within the profession is that orthotists and prosthetists use the
CAD portion to digitize and manipulate the data, then sub­
contract the production of a device from a central fabrication
company for the CAM portion. The art and workmanship
that have distinguished the orthotists and prosthetists from
other health professionals for most of the twentieth century
continue to evolve as CAD/CAM technologies improve the
design, manufacture, and diagnostic aspects of the field.
Orthotics and prosthetics have played an important his­
torical role in the development of medical and surgical ortho­
pedics and rehabilitation. Fundamental concepts that evolved
from orthotic and prosthetic advancements are now basic
principles in rehabilitation. Orthotics and prosthetics have
evolved as sister professions because the technical skills and
knowledge base to prescribe, fabricate, and fit the respective
mechanical devices are similar. Because of this, material and
technological advancements have been shared between these
two rehabilitation specialties.
MATERIALS
In the first part of the twentieth century, orthoses were con­
structed primarily of metal, leather, and fabric, and prosthe­
ses were manufactured from wood and leather. In the last
60 years, however, tremendous technological advancements
have been made in the material sciences. The demand for
strong and lightweight components in the aerospace and
marine industries has produced a variety of new materials
that possess mechanical properties suitable for use in the con­
struction of orthoses and prostheses. New plastics have led
to revolutionary advancements in the profession, permitting
increased durability and strength and significant cosmetic
improvements. Although a multitude of materials are now
available, traditional ones are still in wide use; material selec­
tion depends in part on the individual needs of each patient.
In a rehabilitation team setting, the orthotist and prosthetist
are responsible for choosing the appropriate materials and
components for fabrication because their experience and
training are specialized in this area.
This chapter presents an overview of the general types
of materials used in orthotics and prosthetics for rehabilita­
tion professionals. Publications by the American Society for
Testing and Materials contain specific technical informa­
tion.11 Industry standards established by the International
Organization for Standardization for consumer and patient
protection give the strength requirements for orthotic and
prosthetic components.12
The types of materials used most commonly in current
orthotic and prosthetic practice include leather, metal, wood,
thermoplastic and thermosetting materials, foamed plastics,
and viscoelastic polymers. In deciding which materials are
most appropriate for a patient, the orthotist or prosthetist con­
siders the five important characteristics of materials: strength,
stiffness, durability, density, and corrosion resistance.13
A material's strength is determined by the maximum exter­
nal load that the material can support or sustain. Strength is

Chapter 6  Materials and Technology
145
especially important in lower limb devices, in which loading
forces associated with gait can be very high, or when heavy
use of the orthotic or prosthetic device is anticipated.
Stiffness is the amount of bending or compression that
occurs when a material is loaded (stress/strain or force/
displacement ratios). The stiffer a material, the less flexible it
is and the less likely that deformation will occur during wear.
When significant external stability is desirable (e.g., in a frac­
ture brace or a rigid prosthetic frame), a stiff material is often
chosen. When conformation to body segments is necessary
(e.g., in a posterior leaf-spring AFO or a flexible transfemoral
prosthetic socket), a more flexible material is used.
Durability (fatigue resistance) of a material is deter­
mined by its ability to withstand repeated cycles of loading
or unloading during functional activities. Repeated loading
compromises the material's strength and increases risk of
failure or fracture of the material. Fatigue resistance is espe­
cially problematic in the interface of materials with different
characteristics.
Density is the material's weight per unit of volume, a prime
determinant of energy cost during functional activities while
a patient wears a prosthetic or orthotic device. Although the
goal is to provide as lightweight a device as possible, strength,
durability, and fatigue resistance needs may necessitate a
denser material.
Corrosion resistance is the degree to which the material is
susceptible to chemical degradation. Many of the materials
used for orthoses or prostheses retain heat, making perspira­
tion a problem. For some patients who require lower extrem­
ity devices, incontinence may also be a concern. Materials that
are impervious to moisture are easier to clean than porous
materials.
The ease of fabrication is another important consider­
ation for materials. Certain materials can be easily molded or
adjusted for a custom fit; others require special equipment or
techniques to shape the material.
Leather
Leather is manufactured from the skin and hides of various
animals. Tanning methods and the type of hide determine
the final characteristics of the leather. As an interface mate­
rial for an orthosis or a prosthesis, vegetable-tanned leather
is used to protect the skin from irritation. Chrome-tanned
leather is used for supportive purposes when strength and
resiliency are needed. Additional chemical processes can be
incorporated during manufacturing to produce leathers that
are waterproof, porous, flexible, or stiff. Useful qualities of
leather include its dimensional stability, porosity, and water
vapor permeability.14 These features have made leather a fre­
quently used material within orthopedics, and it continues
to be a material of choice in many current devices. Today,
leather is used for supportive components such as suspen­
sion straps, belts, and limb cuffs. Leather is also used to cover
metallic structures such as pelvic, thigh, and calf bands. For
foot orthoses and shoe modifications, leather is often pre­
ferred over synthetic substitutes because of its superior
“­breathability” characteristics.
Another important attribute of leather is its moldability.
Although numerous techniques are available to mold
leather, the most common one in orthotics and prosthet­
ics is to stretch it over a plaster cast after it has been mulled
(dampened or soaked) in water. When the water evaporates
from the molded leather, its dried shape is maintained, and
the leather can be trimmed to the desired dimensions. To
increase strength and durability, leather can be reinforced by
lamination with plastics or other leathers. Similarly, if pad­
ding is desired over bony regions of the body, foamed plas­
tics or felt can be sandwiched between layers of leather for
comfort or to distribute applied forces over a larger surface
area. Three basic skills are required for crafting orthotic or
prosthetic components of leather: cutting, sewing, and mold­
ing. A technique specific to leather work is that of skiving,
or thinning the edge on the flesh side of the hide. Finishing
methods such as these contribute to the final appearance of
the leather work and the device.
Metals
The types of metal used in the fabrication of orthoses and
prostheses can be categorized into three groups: steel and its
alloys, aluminum, and titanium or magnesium alloys. These
metals may or may not share similar characteristics. If met­
als are incorporated into an orthosis or prosthesis, the choice
of metal is determined by the needs and preferences of the
­particular patient.
Steel
The general term steel refers to any iron-based alloy material.
Carbon alloys have carbon added to the composition of steel.
The term alloy steel is used when other materials are included
in the material manufacture. Alloy steels are further defined
as low-alloy or high-alloy steels. Steels are strong, rigid, duc­
tile, and durable, but their high density (weight) and suscep­
tibility to corrosion are major disadvantages. Many different
types of steel are available to meet various engineering needs.
To assist in identifying the composition and type of mate­
rial, the American Iron Steel Institute–Society of Automotive
Engineers has established a four-digit numbering system. The
first two digits in the number indicate the type of steel, and
the last two digits identify the carbon content. For alloy steels,
the first digit identifies the major alloy and the second digit
indicates the percentage of the major alloying element.
The carbon content of steel is the major determinant of
its ductility and yield strength characteristics. Yield strength
is an offset measure in a stress-strain curve in which strain
occurs without an increase in stress. Ductility is the property
of a material to deform in the inelastic or plastic range. Low
carbon content (0.05% to 0.10%) produces high ductility and
a low yield strength.15 As the carbon concentration increases,
yield strength increases and ductility is reduced. Heat treat­
ments can alter the properties of carbon steel by increasing
yield strength and reducing ductility. The mechanical prop­
erties of low-alloy steels fall between those of carbon steels
and high-alloy steels. High strength/weight ratios are possi­
ble with the high-alloy steels, an important characteristic for

146
Section I  Building Baseline Knowledge
repetitive loading situations. These types of steels are used for
some orthotic and prosthetic joint components. High-alloy
steels are not very resistant to corrosion and are often more
difficult to fabricate.
Stainless steel is a steel alloy that contains 12% or more of
chromium, a material that increases resistance to corrosion
and oxidation. Chromium produces a light oxide film on the
surface that deters deterioration of the base metal. Because
durability and protection from corrosion are highly desirable,
stainless steels are used extensively within orthotics and pros­
thetics to enhance longevity of devices. Two types of stainless
steel, martensitic steel and ferretic steel, have chromium as
the predominant alloying element, but martensitic steel is the
only one used in orthotics and prosthetics because it can be
hardened by heat treatment. Stainless steel is used for orthotic
and prosthetic joints, support uprights, and band material.
Aluminum
Aluminum alloys are well suited for orthotics and prosthet­
ics because of their high strength/weight ratio and resistance to
corrosion. As with steels, the properties of aluminum depend
on alloying compositions, heat treatments, and cold working.
Wrought and cast are terms used to describe the two major types
of aluminum alloys. Alloys are further subdivided into those that
are heat treatable and those that are not. The low ductility and
low strength of cast aluminum are ideal for prefabricated pros­
thetic components and in some assemblies for moving parts.
Wrought aluminum alloys are used in orthotics and pros­
thetics for structural purposes such as prosthetic pylons,
orthotic uprights, and upper extremity devices. The high-
compression bending stresses of lower extremity prosthetics
are well suited to the use of wrought aluminum alloys.
Although aluminum alloys are very resistant to atmo­
spheric and some chemical corrosion, the acids and alkalis
in urine, perspiration, and other bodily fluids deteriorate the
natural protective oxides on the material's surface, making
the aluminum susceptible to corrosion. To deter corrosion in
aluminum and to resist abrasive wear, various hard coatings,
such as anodic or oxide finishes, can be applied. Mechanical
finishes, such as polishing, buffing, and sandblasting, offer
attractive cosmetic appearances for devices.
Titanium and Magnesium
Components made of titanium alloys have become more prev­
alent in prosthetics but are rarely used in orthotics. Although
titanium alloys are stronger than those of aluminum and have
comparable strength to some steels, their density is 60% that
of steel.16 Because prosthetic components made of titanium
are lighter in weight than steel counterparts, they require less
energy expenditure by the patient during use. Titanium alloys
are also more resistant to corrosion than are aluminum and
steel. It is important to note, however, that titanium alloys are
often more difficult to machine and fabricate. Consequently,
titanium is most often used in prefabricated prosthetic compo­
nents, when strength and light weight are of concern. Titanium
is also more expensive than aluminum and steel, which has
been a limiting factor for its use.
Magnesium alloys are lighter than those of aluminum and
titanium, are corrosion resistant, and have a lower modulus
of elasticity than does aluminum. The modulus of elasticity
(Young's modulus) is defined as the ratio of unit stress to unit
strain in a stress-strain curve's elastic range; materials with
low modulus values are associated with lower rates of fatigue
under conditions of repeated stress. Although some of these
features are promising, magnesium alloys have not yet been
widely used in orthoses and prostheses.
Wood
Wood possesses many desirable characteristics for use in pros­
thetics. Its wide availability, strength, light weight, and ability
to be shaped easily have continued to be of benefit in pros­
thetic socket and component construction, even with the
introduction of thermoplastics. The wood used in prosthetics
must be properly cured, free of knots, and relatively strong.
Yellow poplar, willow, basswood (linden), and balsa are most
commonly used. Hardwoods have been reserved for prosthetic
applications in which structural strength is essential, most
often in certain types of prosthetic feet or as reinforcement for
knee units. The keel prosthetic foot is fabricated of maple and
hickory. The solid-ankle, cushioned-heel prosthetic foot has a
hardwood keel that is bolted to the prosthetic shank, creating
a solid structural unit for standing and ambulation.
Plastics and Composites
One of the most important production-related characteristics
of an orthotic or prosthetic material is its ability to be molded
over a positive model. Because plastics can be readily formed,
they are a very popular, widely used material for orthoses and
prostheses. Plastics are grouped into two categories: thermo­
plastics and thermosetting materials.17–19
Thermoplastics
Thermoplastic materials are formable when they are heated but
become rigid after they have cooled. Thermoplastics are clas­
sified as either low-temperature or high-­temperature materi­
als, depending on the temperature range at which they become
malleable. Low-temperature thermoplastics become mold­
able at temperatures less than 149°C and can often be molded
directly on the patient's limb, whereas high-­temperature mate­
rials require heating to much higher temperatures and must be
molded over a positive model of the patient's limb.18 One advan­
tage of thermoplastic materials is that they can be reheated and
shaped multiple times, making possible minor adjustments of
an orthosis or prosthesis during fittings. Thermoplastics are
the material of choice for “shell” designs in which structural
strength is required. Some of the more popular materials used
are acrylic, copolymer, polyethylene, polypropylene, polysty­
rene, and a variety of vinyls.
Certain low-temperature thermoplastics, those moldable at
temperatures less than 80°C, can be applied and shaped directly
to the body. Some of the most commonly available materials
include Kydex (Kleerdex, Aiken, S.C.), Orthoplast (Johnson &
Johnson, Raynham, Mass.), and Polysar (Bayer, Pittsburgh, Pa.).
These materials are most often reserved for orthotic devices

Chapter 6  Materials and Technology
147
that are designed to provide temporary support and protection.
Their susceptibility to repetitive stress, high loads, and tempera­
ture changes usually limits their use to spinal and upper extrem­
ity orthoses. Because these devices are molded directly on the
patient, no casting is necessary, and the time required from
measurement to finished product is greatly reduced. Another
important convenience of low-temperature thermoplastic mate­
rials is that no special equipment is required; hot water heated in
an electric frying pan, a heat gun, and sharp scissors are all that
are necessary to produce a functional splint or orthosis.
High-temperature plastics are frequently used in the pro­
duction of orthotics and prosthetics. The most commonly
used materials include polyethylene, polypropylene, polycar­
bonate, acrylic, acrylonitrile butadiene styrene, acrylics, poly­
vinyl acetate, polyvinyl chloride, and polyvinyl alcohol.
Polypropylene is a rigid plastic material that is rela­
tively inexpensive, lightweight, and easy to thermoform.
Polypropylenes, which can be further characterized as homo­
polymers or copolymers, are one of the most widely used
plastics in orthotics. The material has a white, opaque color
and is available in sheets of various thicknesses, from 1 mm to
1 cm. Polypropylene is impact resistant and can endure sev­
eral million cycles of repetitive flexes. This attribute has been
extremely useful in orthotics for hinge joints and spring assists
in AFOs. The material is, however, susceptible to ultraviolet
light and extreme cold and is sensitive to scratches and nicks.
In prosthetics, the light weight of polypropylene makes it
ideal for components such as sockets, pelvic bands, hip joints,
or knee joints. Polypropylene is commonly used for prefabri­
cated AFOs and preformed modular orthotic systems.
The long fatigue life of polyethylene during repeated loading
situations makes this material suitable for a number of orthotic
and prosthetic applications. Prosthetic sockets, orthotic hinge
joint components, and compression shells for clamshell design
orthoses are common uses of polyethylene plastics. Several
densities of polyethylene are available from various manufac­
turers. Low-density polyethylene is used for upper extremity
and spinal orthoses under the trade names Vitrathene (Stanley
Smith & Co, Ltd, Isleworth, U.K.) and Streifen (FG
Streifeneder KG, Munich, Germany). High-density polyeth­
ylene, Subortholen (Wilhelm Julius Teufel GmbH, Stuttgart,
Germany), is used for spinal and lower extremity orthoses. The
ultra-high-­density polyethylenes such as Ortholen (Wilhelm
Julius Teufel) are used principally for lower extremity orthoses.
Thermoforming
Thermoforming is one of the most common techniques used
in orthotic and prosthetic laboratories to fabricate the “user”
interface components of a device (e.g., prosthetic socket,
AFO). The process of thermoforming entails heating a sheet
of thermoplastic material in an oven until it has reached its
“plastic” state (i.e., ability to distort) and then forcing the
material over a prescribed shape (i.e., positive mold) under
pressure until it has cooled. Negative air pressure or vacuum
is the typical method used to apply pressure and form the
plastic over the mold, hence the terms “vacuum-form” are
also used to describe the process. Once the plastic has cooled
and returned to its solid state, the perimeter of the formed
components is determined and trimmed out. The edges of
the plastic are then finished on specialized grinding machines
that have a diverse set of abrasive sanding and buffing cone
options that are used to achieve a high-polish smoothed edge.
Thermosetting Materials
Thermosets are plastics that are applied over a positive model
in liquid form and then chemically “cured” to solidify and
maintain a desired shape. To enhance their structural proper­
ties, thermosets are often impregnated into various fabrics by
a process of lamination. Although this group of plastics has
inherent structural stability, their rigidity precludes modifi­
cation by heat molding; their shape can only be changed by
grinding. Thermosetting plastics cannot be reheated with­
out destroying their physical properties. Some of the most
common thermoset resins used to produce rigid orthoses
are acrylic, polyester, and epoxy. Because acrylic resins are
strong, lightweight, and somewhat pliable, they offer a differ­
ent set of characteristics than those of polyester resins. With
lamination, acrylic resin can create a thin but strong struc­
tural wall for a prosthetic socket or component of an orthosis.
If frequent adjustments are anticipated, however, thermo­
forming plastics are chosen instead because thermoset can­
not be heated to make adjustments to their shape.
Composites
Composites are the combination of two or more materi­
als with distinctly different physical or chemical properties
that together produce a material with enhanced performance
characteristics relative to their material properties as a sin­
gle substance. Numerous types of composites exist under this
broad descriptive term, ranging from natural materials such
as wood to manmade materials such as concrete. This chapter
focuses on the combination of fibers and matrices associated
with thermosetting plastics.
Fiber-reinforced plastics (FRPs), also referred to as com­
posites, have revolutionized orthotics and prosthetics, pri­
marily because they can be engineered to have mechanical
properties with strength characteristics optimized for spe­
cific types of loading situations, thereby greatly improving
the functionality of many types of orthoses and prostheses.
The mechanical properties of reinforcement fibers, for the
most part, dictate the mechanical properties of a composite
through the orientation and position of the fibers. In general,
FRPs offer high strength and stiffness qualities yet are also
capable of incurring compressive or flexural stresses. Plastics
can also be reinforced with other fillers, particulates, and
short or chopped fibers, but FRPs are most widely used. This
section focuses on fiber reinforcement for thermosets.
Polymer composites are made of a binder material (i.e.,
resin), referred to as the matrix, which is reinforced with
fibers to improve strength and stiffness. The matrix of a com­
posite encapsulates the fibers to maintain their desired orien­
tation and position and ensure that load sharing of fibers is
well distributed through the material. The volume fraction of
resin-to-fiber is an important determinant of the mechanical

148
Section I  Building Baseline Knowledge
properties of a composite and its performance. In general,
the volume of fiber should be higher than the volume of resin
matrix. A fiber volume fraction that approaches 90.7% with a
matrix volume fraction of 9.3% is considered an ideal ratio.20
By comparison, the fibers in composite materials are stron­
ger than the matrix material and can handle stresses applied to
them better than the weaker matrix material. Typical fiber rein­
forcements used in polymer composites are fiberglass, carbon/
graphite, and Kevlar aramid fibers (DuPont, Wilmington, Del.).
Grades of different fiberglass include E, C, and S glass, which
stand for electrical (E), chemical (C), and strength (S), respec­
tively. S glass has a higher tensile strength than E and C glass.
Carbon fiber is widely used in orthoses and prostheses having
strength properties greater than steel while also being light­
weight and very stiff. Carbon fiber has superior stiffness proper­
ties in both compression and tension but, because it has relatively
low impact strength, it is often combined with other reinforce­
ment fibers like fiberglass or Kevlar to improve its performance.
Aramid fibers (e.g., Kevlar) have tensile strength properties that
are five times greater than steel for the same weight.
Laminar composites or laminates are fabricated out of “con­
tinuous fibers” that may extend the length of a given part and
are one of the most common FRPs used in orthotics and pros­
thetics. Continuous fiber reinforcements can be woven into the
form of a fabric in many different weave patterns. By combin­
ing different types of fiber fabrics (e.g., carbon graphite, Kevlar)
and stacking these plies into layers, the resultant laminate can
possess properties for particular modes of loading. When engi­
neering laminates for orthoses and prostheses, the practitioner
or technician must understand the manner in which loads will
be transmitted through a device so that appropriate layering
and orientation of plies will be incorporated into the compos­
ite to meet its functional performance duties. A laminate code
system is used to describe the direction and ply layer with the
longer dimension of the laminate serving as the x-axis and the
width serving as the y-axis. A fiber orientation angle is used to
describe the orientation of plies with respect to the x-axis, which
is designated as 0°. A laminate code describes the sequencing of
each layer from top to bottom. An example of a laminate code
where the top ply is 0° followed by subsequent plies oriented
respectively at 45°, 90°, 45°, with the bottom ply at 0° would be
written as follows: [0/45/90]2. Brackets define the code's begin­
ning and end, and the subscript indicates the adjacent plies
are oriented the same, which is essentially one half of the ply
description. The purpose of having a variety of different fiber
orientation angles in composite laminates is that the load can
be carried through the fibers in a number of different positions.
For example, if the fibers were only oriented in one direction,
then structural loading of the material at a different angle could
result in a failure. Therefore multidirectional laminates have the
capacity to endure loads in an orthotic and prosthetic device in
variety of positions.
Processing Technologies and Composite Fabrication
Orthotic and prosthetic devices often are a compilation of
­custom-molded interface shell components combined with
additional premanufactured parts (e.g., prosthetic foot, pylon).
Practitioners and their technical staff have the capability to
fabricate the human interface portions of a device within
their laboratories, although the processes and equipment in
their labs are limited to only a few techniques. Manufacturers
on the other hand have the capacity to consider a much
wider variety of processing techniques for mass producing
­composite parts and thus take advantage of processing tech­
nologies that can maximize the performance potential of the
material.
The most common method for processing FPR composites
in orthotic prosthetic laboratories is a contact molding tech­
nique called a “vacuum bag” lamination. The technique is rel­
atively simple and does not require any specialized equipment.
A flexible membrane bag of plastic is tightly stretched over
the positive mold part and sealed; then negative air pressure
(i.e., vacuum) is applied between the bag and the mold, draw­
ing the bag tightly to the surface of the mold. A hand layup of
fiber cloth is placed on the mold in a predetermined manner
with regard to the orientation and position of the fibers with
an understanding of how loads will be transmitted through
the structure when it is incorporated into a device. After the
desired layup of fiber and cloth is achieved, a second flex­
ible membrane bag is pulled over the mold, creating an enclo­
sure that can accommodate the wet liquid resin (matrix) part
of the composite. After the resin is poured into an opening
of the second bag and sealed, vacuum inside the enclosure
draws the outer bag toward the mold, pressing the resin
through the fiber in a uniform manner to create a thin-walled
structure of composite that has a high fiber-to-resin ratio. If
the atmospheric pressure that presses on the outside bag is
not adequate to achieve the desired fiber-to-resin ratio, then
the vacuum bag mold construct can be placed into an auto­
clave to create higher pressures on the external bag. Because
most orthotic prosthetic laboratories do not have autoclaves
for such procedures, central fabrication laboratories equipped
with such equipment are being used to a greater extent to
maximize the benefits of pressure processing in composites.
Foamed Plastics
Foamed plastics can be used as a protective interface between
the orthotic or prosthetic and the skin, especially over areas
that are vulnerable to pressure, such as bony prominences.
Foamed plastics are grouped into two classes: open and
closed cell. Cells are created in rubber or polymers in a high-
pressure gassing process.18 The microcell structure allows
the foamed plastic material to be displaced in several planes,
which is an ideal physical property for the reduction of shear
forces. In an open-cell foam, the cells are interrelated (as in a
kitchen sponge); in a closed-cell foam, the cells are separate
from each other. Because closed-cell foams are impervious to
liquids, they are less likely to absorb body fluids such as per­
spiration or urine; however, they do act as insulators and can
be hot when worn for extended periods.
An orthopedic grade of polyethylene foam was introduced
in the 1960s by a British subsidiary of the Union Carbide
Company.21 These closed-cell foams are available in a wide array
of durometer hardness. (Durometer refers to a spring indenture

Chapter 6  Materials and Technology
149
post instrument that is used to measure the resistance to the
compression/hardness of a material.) Polyethylene foams are
commercially available under trade names such as Plastazote
(Hackettstown, N.J.), Pe-Lite, Evazote (Bakelite Xylonite Ltd.,
Croydon, U.K.), and Aliplast (Alimed Inc., Dedham, Mass.).
Various polyethylene foams are used in the manufacture of soft
and rigid orthoses, depending on the density of the material.
Plastazote is a low-temperature, heat-formable foam that has
been used successfully in the treatment and prevention of neu­
ropathic foot lesions.22–25 Its light weight and forgiving qual­
ity to bony prominences make it a desirable interface for the
insensate foot. See Hertzman22 for a complete review of the use
of Plastazote in lower limb orthotics and prosthetics.
Closed-cell foams are also made with synthetic rubber
or polychloroprene. Neoprene is available in various densi­
ties, making the low-durometer versions suitable as liners for
orthoses, whereas the firmer materials are used for posts or
soling for shoes. Spenco (Spenco Medical Corp., Waco, Texas)
is a microcellular neoprene foam that reduces shear forces to
the foot's plantar surface and the occurrence of foot blisters
in athletes.26 The nylon (polyamide)-covered neoprene acts
as a shock absorber while also reducing friction on the foot's
plantar surface.21 Although few of these materials are heat
moldable, most can be conformed without difficulty to the
shallow contours of foot orthoses. Lynco (Apex Foot Health
Industries, Teaneck, N.J.) is an open-cell neoprene foam that
dissipates heat more efficiently than its closed-cell cousin;
however, it does not attenuate shock as well as Spenco.21
Polyurethane open-cell foams are alternatives for top cov­
ers for foot orthoses. They provide good shock absorption and
dissipate heat well. Some of the commercially available open-
cell polyurethane foams include Poron (Rogers Corporation,
Rogers, Conn.), PPT (Professional Protective Technology, Deer
Park, N.Y.), and Vylite (Steins Foot Specialties, Newark, N.J.).
Several studies that compare materials used to fabricate
orthoses have been conducted.27–33 In 1982, Campbell and
colleagues27 conducted compression tests on 31 materials to
determine their suitability for insoles in shoes. Materials were
classified according to stiffness into the categories “very stiff,”
“moderately deformable,” and “highly deformable.” The mod­
erately deformable group of plastics, which included 19 of the
tested foamed plastics, was deemed the most beneficial as an
insole material. Campbell and colleagues27 concluded that
these materials could relieve stress from bony prominences
and transfer the loads to the adjacent soft tissues more effec­
tively than could the very stiff or highly deformable materials.
Studies evaluating shoe insole materials also report them to be
effective at attenuating shock during walking in various ways.33
Viscoelastic Polymers
A viscoelastic solid is a material that possesses the characteris­
tics of stress relaxation and creep. Stress relaxation occurs when
a material that is subjected to a constant deformation requires
a decreasing load with time to maintain a steady state.34 Creep
refers to the increase in deformation with time to a steady
state as a constant load is applied.34 Sorbothane (Sorbothane,
Inc., Kent, Ohio), widely used as an insole ­material, is made
of a noncellular polyurethane derivative that possesses good
shock-attenuating characteristics.34 Viscolas (Viscolas Corp.,
Soddy Daisy, Tenn.), another type of viscoelastic solid, has
been found to attenuate skeletal shock at heel strike in the tibia
to half the normal load.15,35 Two other viscoelastic polymers
used to fabricate orthotic prosthetic components are Viscolite
(Polymer Dynamics, Inc., Allentown, Pa.) and PQ (Riecken's
Orthotic Laboratories, Evansville, Ind.).
PRESCRIPTION GUIDELINES
The formulation of a prescription for an orthosis or prosthe­
sis greatly influences the potential functional outcome for the
patient. It is critical that rehabilitation objectives and design
criteria be carefully considered. Physicians, therapists, ortho­
tists, and prosthetists who are involved in developing a pre­
scription for an orthotic or prosthetic device must have a
sound understanding of orthotics and prosthetics to be suc­
cessful in effectively treating patients with these devices.
Assessment of functional deficit includes a thorough evalu­
ation of the patient's present physical status, including muscle
strength testing, range of motion measures, and documenta­
tion of other physical impairments that would affect the fit or
performance of the device. Equally important to the physical
examination is the consideration of any individual needs of
the patient and an understanding of how the treatment will
affect daily activities. To increase the success of treatment, the
patient and other rehabilitation team members must reach a
consensus on the type of device and the associated training
and education required for optimal functional outcome.
Orthotic Prescription
The Committee on Prosthetics and Orthotics of the American
Academy of Orthopaedic Surgeons developed a technical
analysis form to standardize the process of patient evalua­
tion. This evaluation protocol documents the biomechani­
cal deficits of the patient and provides the basic information
needed for orthotic prescription formulation. This systematic
approach has two major objectives: to define the anatomical
segments that the orthosis will encompass and to accurately
describe the biomechanical controls needed for treatment.
The underlying principle of this assessment is that orthoses
should be designed to control only those movements consid­
ered abnormal while permitting free motion in anatomical
segments that are not impaired.
Technical analysis forms were developed for three general
regions of the body: the upper limb, lower limb, and spine. The
forms are four pages long with the same basic approach for for­
mulating an orthotic prescription. The first page has sections
for recording general patient information and noting major
physical impairments (Figure  6-1). The major impairment
section characterizes any functional limitations, such as skel­
etal structure, sensation, or joint contracture. This informa­
tion provides an overview of the patient's clinical presentation.
The second and third pages of the technical analysis form
(Figure 6-2) contain diagrams of the respective anatomical
(limb or trunk) segments for which an orthotic ­prescription is

150
Section I  Building Baseline Knowledge
Technical Analysis Form
Name
Date of onset
Occupation
No.
Age
Sex
Cause
Present lower-limb equipment
Diagnosis
Ambulatory
Major impairments:
A.
Skeletal
1.
2.
Bone and joints:
Normal
B.
Sensation:
C.
Skin:
Normal
D.
Vascular:
Normal
Abnormal
E.
Balance:
F.
Gait deviations:
G.
Other impairments:
Legend
Normal
Impaired
Support:
Volitional force (V)
N = Normal
G = Good
F = Fair
P = Poor
T = Trace
Z = Zero

= Direction of translatory


motion
60°
30°
1 cm.

= Abnormal degree of


rotary motion

= Fixed position

= Fracture
Proprioception (P)
N = Normal
I = Impaired
A = Absent
D = Local distension or


enlargement

= Pseudarthrosis

= Absence of segment
Hypertonic muscle (H)
N = Normal
M = Mild
Mo = Moderate
S = Severe
Right
Left
Abnormal:
Normal
Abnormal
1.
Anesthesia
2.
Pain
Location:
Protective sensation:
Retained
Lost
Hypesthesia
Location:
Ligaments:
Normal
3.
Extremity shortening:
None
Amount of discrepancy:
ASIS-Heel
ASIS-MTP
MTP-Heel
Left
Right
Abnormal
Abnormal
Knee: AC
PC
Ankle: MC
LC
MC
LC
Nonambulatory
Lower Limb
Revised March 1973
FIGURE 6-1  The technical analysis form provides a systematic method of data collection for the
development of prescriptions for lower extremity orthoses. The first page of the form is used to record
the patient's history and current impairments. AC, Anterior cruciate ligament; ASIS, anterior supe­
rior iliac spine; LC, lateral collateral ligament; MC, medial collateral ligament; MTP, medial tibial pla­
teau; PC, posterior cruciate ligament. (From Committee on Prosthetics Research and Development.
Report of the Seventh Workshop Panel on Lower Extremity Orthoses of the Subcommittee on Design
and Development. Washington, DC: National Research Council–National Academy of Sciences,
1970; and McCollough NC III. Biomechanical analysis systems for orthotic prescription. In American
Academy of Orthopaedic Surgeons, Atlas of Orthotics: Biomechanical Principles and Application,
2nd ed. St. Louis: Mosby, 1985. pp. 35-75.)

V
Sagittal
Anterior
Posterior
H
V
H
V
P
P
P
H
V
H
V
H
V
V
H
V
H
H
V
H
V
H
Coronal
Medial
Lateral
Transverse
Medial
Lateral
Left
Subtalar
Ankle
Tibia
Upper
Middle
Lower
Knee
Femur
Hip
Upper
Middle
Lower
FIGURE 6-2  Subsequent pages of the technical analysis form are used to detail characteristics of each limb
or body segment for which the orthosis or prosthesis will be made. Information recorded on these pages
includes existing deformity, proprioceptive capacity (P), restriction or hypermobility of joint rotary and
translatory range of motion in all three planes of movement, volitional strength (V), and the level of hyperto­
nicity (H). (From Committee on Prosthetics Research and Development. Report of the Seventh Workshop
Panel on Lower Extremity Orthoses of the Subcommittee on Design and Development. Washington, DC:
National Research Council–National Academy of Sciences, 1970; and McCollough NC III. Biomechanical
analysis systems for orthotic prescription. In American Academy of Orthopaedic Surgeons, Atlas of
Orthotics: Biomechanical Principles and Application, 2nd ed. St. Louis: Mosby, 1985. pp. 35-75.)

152
Section I  Building Baseline Knowledge
being considered. Each skeletal region is represented in three
planes of motion: coronal, sagittal, and transverse. On either
side of the figures, square boxes at the level of the joints are
used to note volitional force, hypertonicity, proprioception,
and range of motion. The fourth page consists of a summary
of the functional disability, treatment objectives, orthotic rec­
ommendation, and a key for the biomechanical controls of
function.
Voluntary movements of muscles are assessed by con­
ventional muscle testing techniques. Muscle strength can
be recorded with either the standard descriptive or numeric
muscle grading systems, depending on regional preferences.
Two types of joint (limb) motion are recorded on the forms:
rotary and translatory. According to McCollough,36 all points
of the distal segment move in the same direction, following
the same path shape and distance during translatory motion.
During rotary motion, one point of the distal segment (or its
imaginary extension) remains fixed while other points move
in an arc around it. Translatory motion is recorded with linear
arrows in the direction of the distal segment's movement rela­
tive to its proximal counterpart. The linear arrows are placed
below the circle (representing the joint axis) for translatory
motion. If translatory force acts in the vertical axis, the lin­
ear arrow is placed to the side of the circle. Rotary motion
and the related degree of range of motion are documented
by an arrow within a protractor-type arrangement for each
joint. The established normal range of motion for each joint
is shaded on the form for comparative reference. If a fixed
contracture or fusion of the joint is present, a double linear
arrow is used.
Hypertonicity of muscle groups in each of the body seg­
ments is described by a functionally based letter scale.36 A des­
ignation of mild tonicity is given when any hypertonus that is
present is thought to be functionally insignificant. Moderate
tonicity indicates that tone might have some functional value,
such as assisting the patient in holding an item during minor
tasks. A designation of severe tonicity indicates that normal
function is not possible. The patient's proprioceptive ability is
described in a similar way, as absent, impaired, or normal for
each of the body segments of interest.
The final page of the technical analysis form (Figure 6-3)
contains space for an overview of functional impairments, a
checklist of the orthotic treatment objectives, and a chart that
details the orthotic recommendation. The desired orthotic
control for each body segment is indicated by a specific letter;
as many as seven types of orthotic controls can be incorpo­
rated into the design of an orthosis. The terms and descrip­
tions of these controls are indicated in the key. If the orthotic
recommendation section is completed correctly, the chart will
indicate the body segments that the device will encompass and
the desired biomechanical control of function needed. Any
comments on the specific design requirements or materials,
or both, can be detailed in the remarks section of the form.
For the orthotist, the prescription is the blueprint from
which the design of a device is based. It specifies the force sys­
tem requirements needed to achieve the treatment ­objectives
independent of material selection or production processes.
Although an in-depth biomechanical assessment may not
always be necessary, a system based on these principles is a
logical and objective method for formulating an orthotic
prescription.
Prosthetic Prescription
The formulation of a prosthetic prescription requires a dif­
ferent evaluative process. Prosthetic prescription depends on
an in-depth understanding of components and materials as
well as their indications and contraindications for use. Ideally,
prosthetic prescription begins before amputation surgery, so
the residual limb is of appropriate length and healing is ade­
quate for optimal prosthetic use. Factors such as vascular sup­
ply, anticipated activity level, intelligence, vocation, and age
are also important to consider. Range of motion, flexible and
fixed contracture, functional strength, skin condition, girth
measurements, pain, and sensation of the residual limb and
the intact limb are evaluated.
An important part of prosthetic prescription is component
selection. The diversity of prosthetic foot-ankle units and
knee mechanisms for lower extremity prosthetics, and the
variety of terminal devices for the upper extremity, can pres­
ent difficult decisions for those who are unfamiliar with their
intended application. Therefore, prosthetists are often relied
on for recommendations on components because they are
usually most familiar with the specifications and limitations.
Many prosthetic teams have developed data collection forms
to standardize the prosthetic prescription process. Redhead37
suggests that the prescription for a prosthesis consider each
of the major “prescription options.” Examples of the specifi­
cations delineated by Redhead for a transfemoral prosthesis
are type of limb, socket material and design, suspension, knee
joints, knee controls, ankle joints, feet, and cosmesis.
FABRICATION PROCESS
Once a prescription for a custom orthosis or prosthesis has
been created, the fabrication process begins. The traditional
fabrication process is composed of six steps:
Step 1: Taking accurate measurements of the limb
Step 2: Making a negative impression (cast)
Step 3: Creating a three-dimensional positive model of the limb
or body segment
Step 4: Modifying the positive model to incorporate the desired
controls
Step 5: Fabricating the orthosis or prosthetic socket around the
positive model
Step 6: Fitting of the device to the patient
In some instances, further modification or adjustment is
necessary to achieve optimal fit and function of the device.
Measurement
Measurements are most often referenced from readily pal­
pable bony landmarks. Important measurements include
the length, successive circumferences, and mediolateral and
anteroposterior dimensions of the body segment for which
the orthotic or prosthetic device is being created. Although

Chapter 6  Materials and Technology
153
Summary of functional disability
Treatment objectives:
Prevent/correct deformity
Orthotic Recommendation
Reduce axial load
Protect joint
Improve ambulation
Fracture treatment
Other
Signature
Remarks:
Lower limb
Flex
Ext
Abd
Add
Axial
load
Rotation
Int
Ext
HKAO
Hip
KAO
Thigh
AFO Leg
FO Foot
Subtalar
Midtarsal
Met-phal
Ankle
(Dorsi)
(Plantar)
(Inver)
(Ever)
Knee
Date
F = Free
A = Assist
R = Resist
S = Stop
v = Variable
H = Hold
L = Lock
Use the following symbols to indicate desired control of designated function:
Key:
Free motion
Application of an external force for the purpose of increasing the range, velocity, or
force of a motion
Application of an external force for the purpose of decreasing the velocity or force
of a motion
Inclusion of a static unit to deter an undesired motion in one direction
A unit that can be adjusted without making a structural change
Elimination of all motion in prescribed plane (verify position)
Device includes an optional lock
{
FIGURE  6-3  The final page of the technical analysis form details the goals for the orthosis and
the specific prescription for the desired device. Once the prescription is developed, the form serves
as a guideline for fabricating and fitting the orthosis. FO, Foot orthosis; HKAO, hip-knee-ankle
orthosis; V, volitional force. (From Committee on Prosthetics Research and Development. Report
of the Seventh Workshop Panel on Lower Extremity Orthoses of the Subcommittee on Design and
Development. Washington, DC: National Research Council–National Academy of Sciences, 1970;
and McCollough NC III. Biomechanical analysis systems for orthotic prescription. In American
Academy of Orthopaedic Surgeons, Atlas of Orthotics: Biomechanical Principles and Application,
2nd ed. St. Louis: Mosby, 1985. pp. 35-75.)

154
Section I  Building Baseline Knowledge
many measurements can be obtained with simple tools such
as a tape measure, specialized measurement devices such as
electronic scanning devices have been developed to enhance
accuracy and reproducibility. Measurements are recorded on
forms that are specific to the body segment being treated,
such as the technical analysis form previously described.
These measurements are used in two ways: as a reference
when modifications to the positive cast are needed and as the
way to determine the placement of the perimeter trimlines of
the device.
Negative Mold
A negative impression is a mold taken of an actual body part
that is used to create the three-dimensional positive cast or
model necessary for fabrication of the orthosis or prosthesis.
This negative impression is most often taken with a plaster of
Paris bandage or fiber resin tape, although in some instances
direct impressions are used as an alternative. Creation of a
negative impression has four steps. First, a layer of tubu­
lar stockinet or a stocking is placed over the skin to create
a protective interface and control the position of soft tissue
structures within the cast (Figure 6-4). Tubular stockinettes
are available in sizes that range from small diameter for the
pediatric limb to large diameter for the adult torso. When a
direct impression technique is being performed, a topical sep­
arator such as petroleum jelly can be used as an interface to
minimize the risk of capturing cuticle hair in the impression.
Second, bony prominences or other important guiding land­
marks are marked on the body segment with indelible ink.
These marks transfer to the inside of the negative mold and
from there to the surface of the positive model.
Once the limb or body segment has been prepared, a thin
layer of plaster of Paris or fiber resin tape is applied (see
Figure  6-4B). This procedure differs from that of fracture
casts in one important way: the goal is to achieve an “inti­
mate” fit that captures the actual contours of the limb or body
segment so that no protective padding is required. Rolls of
elasticized plaster can be wrapped circumferentially in no
more than two or three layers. Alternatively, strips of the
material can be laid along the length of the limb or body seg­
ment. Most impression casting materials are readily available
in roll form, although special versions have been produced
for specific types of impression procedures, such as the fiber
resin sock for an AFO. As the molding material is applied, the
clinician smoothes the surface, following the normal shape
of the limb. While the mold hardens, the clinician supports
the limb or segment in the desired position, sometimes apply­
ing a light corrective force. As an example, the desired limb
position of an orthosis incorporating the ankle joint might be
in subtalar and talocrural neutral. If a PTB socket design is
desired for a transtibial prosthesis, an extra force applied just
distal to the patella marks its desired location on the resulting
positive mold.
Once the cast is hardened sufficiently, it is carefully removed
from the limb segment, preserving its shape and contours, and
checked for alignment (see Figure 6-4C and D). It is essen­
tial that the clinician who takes the negative impression has a
thorough understanding of the forces that will be applied to
the anatomical segments involved to ensure optimal fit and
function of the orthosis or prosthesis. Estimates of soft tissue
compression and skeletal alignment changes need to be care­
fully considered during the negative impression procedure.
A skilled and experienced professional uses clinical judgment
to create a negative impression, not only to capture the shape of
the anatomical segment but also to apply an efficient force sys­
tem to improve or maximize function. Basic design decisions
must be made before the impression procedures so that any
special accommodations required for the desired functional
outcome can be incorporated.
Special negative impression techniques have been devel­
oped for specific purposes. Polystyrene foam impression blocks
are one of the common methods of acquiring an impression
A
C
B
D
FIGURE  6-4  The procedure for taking a conventional negative
impression begins with placing a layer of cotton stockinette over the
limb and marking bony prominences with an indelible water-soluble
transfer pencil (A). Surgical tubing is positioned on the anterior
aspect of the limb to serve as a guideline for cast removal and to pro­
tect the shin. The limb is positioned on a shoe “last” impression in
preparation for circumferential application of a plaster of Paris ban­
dage or fiber resin casting tape (B). The impression board allows the
foot to assume the contours of a shoe during molding for an optimal
foot/shoe/AFO interface. Once the cast is “set,” a cast saw is used to
open the front of the cast (C), and the negative impression is care­
fully removed from the limb. The anterior edges are closed, and the
ankle-foot alignment of the negative impression is verified with a
plumb line (D).

Chapter 6  Materials and Technology
155
of the plantar surface of the foot.38 For patients who are
recovering from facial burns, fabrication of a facial orthotic
designed to deliver even, steady pressure during the period of
scar maturation requires a highly detailed mold of the face.
Alginate impressions, also referred to as moulage techniques,
similar to those used in dentistry, are often used.
Fabricating and Modifying the Positive Model
Conventional methods for creating a positive cast are well
established. The negative impression is prepared by seal­
ing the mold so that it can accept liquid plaster of Paris.
A separator material (e.g., silicone, soap) is added to the inner
walls of the mold before the plaster of Paris is poured so that
it can be removed more easily once the positive model has
set. Once the cast has solidified, the negative impression is
stripped away and discarded. The anatomical landmarks and
reference points marked on the limb or body segment with
indelible pencil and transferred from the patient to the nega­
tive impression are again transferred to the positive model.
A mandrel (post) is embedded into the setting plaster of the
positive model. This mandrel is used to hold the model for
cast rectification and the rest of the production processes.
Model rectifications remove artifacts produced during the
molding or impression process and bring the cast to specifi­
cation of the measured values taken from the patient. Once
the positive model has been rectified, further modifica­
tions can be made on the basis of the design of the orthosis
or prosthesis being fabricated. During the negative impres­
sion procedure, soft tissue may have been manipulated for
specific applications of force or pressure to be incorporated
into the final orthosis or prosthesis. Although the positive
model represents a three-dimensional shape of a respective
body segment, it cannot relay information about the density
of the tissue that it will interface. In general, additional plas­
ter is added where relief of pressure is desired (e.g., over bony
prominences) (Figure  6-5) or is removed where additional
forces are to be applied. When the orthosis or prosthesis is
formed over the model, an area of relief for a more intimate fit
is achieved. Although some guidelines have been established
regarding the amount of material to be removed or added to
the positive model, the clinical experience of the prosthetist
or orthotist is essential in this stage of the process. The posi­
tive model can also be modified to reconfigure surface geom­
etry to improve the strength of the finished product.
Once design changes have been incorporated into the
model, its surface is prepared for component production.
This involves removing any surface imperfections with abra­
sive tools and abrasive sanding screen to ensure that the sur­
face in contact with skin will be smooth. The positive cast is
then ready to be used as a form from which different materi­
als can be shaped to produce an interface component.
Fabricating the Orthosis or Prosthetic Socket
The fabrication process used with the positive model depends
on the material selected for the device. Thermoforming is a
common production method used in orthotics and prosthet­
ics. Thermoplastic sheet material is heated in an oven until
it has reached its “plastic” state, then shaped over a positive
model by changing the air pressure difference across its sur­
face (vacuum forming) (Figure  6-6). Once the plastic has
cooled and returned to its solid state, trimlines aredelin­
eated on the formed plastic before the edges are finished and
smoothed.
CAD/CAM
In the 1960s, an alternative method of prosthetic fabrication
that used computers was first introduced. Early CAD/CAM
methods used stereophotography and digitization to create
a numerical model, which guided a milling machine in the
creation of a positive model of the residual limb.2 A more
complete concept of fabrication and manufacture of a pros­
thesis was developed at the University College London in
the late 1970s and early 1980s.39 After establishing a system
for automated production of a prosthesis called Rapidform,
the London research group conceived a completely auto­
mated fabrication process that used appropriate prosthetic
alignment data.40
In the United States, the Veterans Administration
began funding research projects in the 1980s to investigate
A
B
FIGURE  6-5  In the rectification of a positive model, plaster of
Paris added over pressure-sensitive areas, such as the lateral mal­
leolus (A), results in a “relief” in the finished orthosis. Modification
of the positive model by removal of material with a plaster rasp over
pressure-tolerant areas (B) increases intimacy of fit for better load­
ing or stabilizing of the limb.

156
Section I  Building Baseline Knowledge
the potential of CAD/CAM in orthotics and prosthetics.
Advances were also made in private industry as the availabil­
ity of personal computers became widespread. Beginning in
the late 1980s, manufacturers have designed a multitude of
CAD/CAM systems for various applications in orthotics and
prosthetics. Advances in computer hardware, processors, and
software have made CAD/CAM systems fast and efficient as
well as an economical alternative for fabrication of devices for
many orthotic and prosthetic practices.
Today, most CAD systems use a scanning device to record
digital information of a body segment for CAM. The primary
components of a CAD/CAM system consist of a digitizing
device, computer, and milling machine. Surface contours of
the anatomical segment are recorded with various digitiza­
tion devices: optical-laser scanners, surface-contacting stylus,
and pneumatically operated mechanical posts. Digital infor­
mation acquired from a scan of a body segment is processed
by the computer and translated into a triordinate data point
file. This file is used by the computer to create a graphic image
in the form of a surface contour plot.41 The data are then
relayed to a milling unit to carve an orthosis or prosthesis
for a positive model.
Data Acquisition
Each of the many digitizers used for data acquisition is
designed for a specific task or to handle certain anatomical
regions. Noncontact laser digitizers capable of circumferential
scanning are well suited for measurement of cylindrical shapes
such as those found in limb prosthetics or spinal orthot­
ics. An optical-laser camera mechanism images the surface
topography of the body segment and records the measured
data points in a computer. Special holding fixtures and bars
to aid in patient comfort and safety are part of each system.
An apparatus designed to scan the torso for a spinal ortho­
sis usually requires a different setup than that of a limb pros­
thesis. Some scanners are capable of digitizing directly from
the patient's body segment, whereas other systems take mea­
surements from a negative impression or mold of the segment
(Figure 6-7). Compact, handheld contact digitizers have been
introduced by several CAD/CAM manufacturers. These units
allow the clinician to digitize a body segment by direct con­
tact with the skin. Handheld contact digitizers are described
A
B
FIGURE 6-6  Once a sheet of thermoplastic material has been heated,
it is dropped over the rectified positive model (A) and the edges of
the thermoplastic are sealed. Negative pressure created by a vacuum
pump removes any trapped air and draws the polypropylene to the
surface of the positive model. When the material has cooled, trimlines
are drawn on the formed plastic (B) by using measurements taken
during the initial evaluation and bony landmarks as guides. Note the
corrugations incorporated to strengthen the orthosis at the ankle.
A
B
FIGURE  6-7  Examples of CAD/CAM data acquisition systems.
A digital model of the residual limb (A) can be captured by a laptop
computer, appropriate signal processor components, and a handheld
digitizer. Laser digitization (B) can be used to capture accurately the
contours of a conventional negative impression of a residual limb.
(Courtesy BioSculptor Corporation, Hialeah, Fla.)

Chapter 6  Materials and Technology
157
as a wand, pen, stylus, or pointer. Contact digitizers often have
special attachments to scan certain shapes or measurement
tools, such as calipers, for acquiring anteroposterior or medio­
lateral dimensions. Their versatility permits data acquisition
of complex shapes. In some systems, handheld digitizers can
be used in conjunction with a laser scan.
The use of digitizers in the production of foot orthoses is
also becoming more common. Several systems based on differ­
ences in technique and philosophy in foot orthosis design have
been developed for data acquisition of the foot. For full weight-
bearing or partial weight-bearing techniques, pneumatically
operated mechanical posts are used to digitize the foot's plantar
surface (Amfit Corp, Vancouver, Wash.). Orthotic contoured
shapes such as metatarsal domes can be evaluated during the
digitization procedure to determine optimal position and
comfort before fabrication. An optical-laser scanner situated
under an acrylic platform has also been used for scanning the
foot when a weight-bearing technique is desired (Bergmann
Orthotics Lab, Northfield, Ill.). Because this system is also
capable of scanning the foot with non–weight-bearing meth­
ods without the platform, it is quite versatile in clinical practice.
In many instances, orthotists and prosthetists are restricted
to surface geometry and palpation of underlying anatomical
structures to interpret the position of skeletal and soft tissue
structures of the body segment. Magnetic resonance imaging
and computed tomography have been used to create a three-
dimensional computer model and assist in making design
decisions for a mechanical device (Figure  6-8). Data from
these scans are converted to a working format for specific
graphic and modeling programs. Although this capability
may not be practical for all applications, it may offer insight
into areas of further research and development in the field.
Shape-Manipulation Software
The ability to modify the three-dimensional model of a
patient's body segment permits the clinician to incorporate
the desired biomechanical controls into an orthosis or pros­
thesis. The amount of force applied to a specific area depends
in part on manipulation of the digital three-dimensional
model. Software packages are now available to assist orthotists
and prosthetists in designing the most appropriate modifica­
tions for a given patient. Generic modification templates or
custom-designed templates can be used to make a wide range
of revisions to the data. The clinician can incorporate reliefs
for bony prominences of the limb or trunk or can change the
geometry of the shape to enhance structural strength charac­
teristics in the final orthosis or prosthesis. Trimlines can be
delineated so that technicians who are involved in the assem­
bly of components can complete a device without further
instruction.
Milling and Production
Once the digital model is in place, the milling apparatus cre­
ates the actual orthotic or prosthetic device. Because each type
of orthosis or prosthesis usually has specific milling param­
eters, a different setup may be required for each. For instance,
the long, rounded shape of a transtibial or transfemoral
socket is often manufactured with a lathe-type milling
machine (Figure 6-9). In contrast, foot orthoses are manu­
factured by an end mill setup because their platelike structure
and production processes create different finishing needs. The
production laboratory needs to be large enough to have sepa­
rate milling stations for each type of orthosis or prosthesis.
This manufacturing limitation has led to the establishment of
laboratory production companies that mill the positive mod­
els and manufacture the orthoses or prostheses from com­
puter data transmitted by modem. Computer production
networks can often reduce fabrication time and decrease pro­
duction times, making the use of CAD/CAM economically
feasible even for small orthotic/prosthetic facilities. Special
production equipment is available that partially automates
the thermoforming processes of some components. In the
thermoforming machine for prosthetic sockets, a preformed
polypropylene shell travels upward on a mechanical platform
to an oven that heats the plastic to its formable temperature.
The heated shell is then lowered over the positive model of
the residual limb and vacuum formed for an intimate fit.
FIGURE  6-8  Computed tomographic or magnetic resonance
images can be used to create a digitized computer model of a body
segment for various orthotic or prosthetic CAD/CAM applications.
The components of this type of system include an image scanner
(foreground), a computer monitor for display of digitized images
(e.g., the torso; center right), and the computed tomographic or
magnetic resonance images being used (background). (Courtesy
BioSculptor Corporation, Hialeah, Fla.)

158
Section I  Building Baseline Knowledge
CAD/CAM in orthotics and prosthetics will play an
important role in clinical and research settings. Although the
development of CAD/CAM in orthotics and prosthetics has
a history that spans more than two decades, only since the
1990s has it become an integral part of some clinical practices.
Systems that have been designed for virtually all prosthetic
and orthotic applications can be integrated with computed
tomography, magnetic resonance imaging, and other medi­
cal imaging technologies. The technological advancements
of CAD/CAM offer orthotists and prosthetists an additional
clinical fabrication and research tool. Although this sophisti­
cated equipment can contribute greatly to certain clinical and
manufacturing tasks, successful fitting of a device depends on
proper data input and prescription formulation.
CENTRAL FABRICATION AND MASS
PRODUCTION
The techniques and processes associated with the fabrica­
tion of orthoses and prostheses described in this chapter can
be relatively labor intensive and expensive. As managed care
and insurance companies strive to reduce medical costs, the
profession is under greater pressure to remain competitive by
finding alternative production methods that are cost effec­
tive. One option is to maximize the clinical productivity of
orthotists and prosthetists and limit their technical respon­
sibilities. Central fabrication operations allow practitioners
to develop clinical practices that do not require large techni­
cal facilities and space. Depending on the size of the practice,
outsourcing the production portion of the business can be a
more economical way to run an orthotic/prosthetic clinic.
Some practitioners do not want to manage in-house techni­
cal operations that include additional technical staff, special­
ized equipment, and increased space requirements. Another
advantage is that central fabrication may offer improvements
in consistency and quality of devices.
Central Fabrication Facilities for Custom Devices
Central fabrication facilities typically specialize in the man­
ufacture of custom orthoses and prostheses, often serving a
large number of orthotic and prosthetic practices. These man­
ufacturing services are available to produce almost every kind
of orthosis and prosthesis, with many companies specializing
in a specific area (e.g., spinal orthoses, knee orthoses, trans­
tibial prosthetics). Some central fabrication operations offer
the advantage of producing a device without the need for a
negative impression, an additional cost savings in time and
materials. A series of conventional measurements of patients
combined with height and weight data is entered into a com­
puter to generate a milled positive model for production.
Orthotic systems in particular have been refined to produce
excellent fitting devices that are comparable in function to
custom-molded orthoses produced from a patient model.
Although there will always be a need for custom-molded
devices, technological advancements in human factors, ergo­
nomics, and computer modeling will improve generic sizing
and contoured interface systems, permitting a larger por­
tion of the population to be fit with prefabricated devices and
components. Modular components of varying material prop­
erties are already a part of general practice in prosthetics.
Mass Production
Mass-produced, prefabricated orthoses outnumber custom-
molded orthoses fitted to patients for rehabilitative purposes.
Orthopedic companies continue to develop orthotic and pros­
thetic products whose fit and performance approach that of
custom-molded devices through diverse sizing systems and
modular components. In the future, prefabricated modular
component systems may bridge the gap between prefabricated
and custom-molded devices by improving performance out­
comes with custom-fitted systems and expanding their use in
clinical practice. Although these advances in fit and function
are possible for some problems, certain deformities and path­
ological conditions will almost always require custom-molded
or measured orthoses and prostheses made by traditional or
CAD/CAM methods of production.
MAINTENANCE OF ORTHOSES AND
PROSTHESES
Routine care and maintenance of orthoses and prostheses
are important for proper function and long-term use of a
device. An orthotic or prosthetic maintenance program usu­
ally includes servicing by the orthotist or prosthetist and the
patient. The service schedule depends on the specific orthosis
or prosthesis, the materials from which it is made, the dura­
bility of the components, and the knowledge and ability of
the patient and caregivers. Patient instructions for the daily
care of an orthosis or prosthesis should include cleaning and
inspection. Proper patient education of basic fitting criteria
and instructions on donning and doffing a device allow the
patient to evaluate the fit of a device during routine use.
Orthoses and prostheses should be inspected weekly for
any defects, stress risers (nicks, scratches), loose screws, or
FIGURE  6-9  A positive model for a transtibial prosthetic socket
being carved on a computer-controlled milling/lathe machine.
(Courtesy Prosthetic Design, Inc., Clayton, Ohio.)

Chapter 6  Materials and Technology
159
weakened rivets. Any device that has mechanical compo­
nents and moving parts and is subjected to repetitive loading
requires periodic servicing; it is less expensive to recognize
and fix early signs of a problem than it is to replace a device
that has failed because of a lack of proper maintenance.
Informing patients of potential problems associated with the
use of their orthoses or prostheses and how to resolve these
problems can prevent serious problems from arising.
Most plastic components should be cleaned with a mild
antibacterial soap and rinsed thoroughly with cold water.
Extra moisture should be absorbed with a towel and the
orthosis or prosthesis air dried. Heat can distort some plas­
tics; patients should be warned not to use electric hairdry­
ers to dry their devices. Similarly, devices should not be left
near direct heat sources, such as radiators, wood stoves, or
any appliance that generates heat when running. They must
also be protected from intense direct sunlight.
Leather liners and covers are cleaned weekly with a leather
“saddle” soap. Leather softeners should not be used unless
directed by the orthotist because they can compromise func­
tion of some straps and cuffs. Water-repellent treatments and
protectants for leather often contain skin irritants and should
not be used on leather components that have direct contact
with the body.
Most orthoses and prostheses are designed to apply a cor­
rective or stabilizing force to a body segment during wear. For
some patients, especially those with fragile skin or scarring,
this pressure may increase the risk of skin irritation or dam­
age. The risk of skin problems differs from device to device
and depends on the general health and skin condition of the
individual who is wearing the orthosis or prosthesis. To min­
imize problems with skin intolerance of these extra forces,
most new orthotic or prosthetic users begin with an intermit­
tent wearing schedule. A treatment plan that incorporates a
gradual buildup of orthotic or prosthetic use can avert com­
plications such as excessive redness, chafing, and blisters. For
a patient with a high risk for or a history of skin problems, a
variety of preventive measures (e.g., foam or silicone inter­
face liners) can be incorporated into the orthotic or prosthetic
system.
Most custom orthoses or prostheses are designed to
achieve a very intimate fit with the body segments that they
encompass. Changes in the physical condition of a patient
can ­significantly alter the fit and function of a device.
Compromised fit occurs most often when the patient has
had significant growth, weight gain or loss, muscle atro­
phy, edema, structural degeneration, or trauma. Periodic
evaluations are necessary to ensure that fit and function are
maintained in the months and years after the initial fitting.
Semiannual or annual checkups should be part of the treat­
ment plans for definitive orthotic and prosthetic devices.
To maintain proper function of a lower extremity pros­
thesis, special attention is needed in several areas. The align­
ment of a prosthesis is usually based on a specific heel height;
variation from the prescribed heel height (when footwear is
changed) often leads to functional problems during gait. In
the same way, moderate to excessive wear of the shoe at the
heel also compromises performance. The condition of foot­
wear must be carefully and frequently monitored. The pros­
thesis should be free of dirt, sand, and other debris to ensure
that joint mechanisms and their movements are not inhib­
ited. Socket attachment and suspension systems need daily
attention because they are usually prone to accumulation of
lint, dirt, and other debris. If the prosthesis or any of its com­
ponents are subjected to water, the device should be thor­
oughly dried to prevent permanent damage. Rubber bumpers
in prosthetic feet deteriorate over time and with use and must
be replaced regularly. The prosthetist can advise patients on
specific parts that require regular maintenance.
The socket portion of a prosthesis should be faithfully
cared for to avoid potential skin problems, especially infec­
tion, on the residual limb. When a special liner is used with
a prosthesis, specific instructions for cleaning are necessary
because materials used vary greatly. For patients who are fit­
ted with suction sockets or special socket attachment mecha­
nisms, the joining components or threads should be cleaned
with a soft brush or rag to remove debris.
SUMMARY
This chapter explores the materials and methods most com­
monly used in the prescription, measurement, and produc­
tion of orthoses and prostheses. The type of design, materials,
and components are selected to best facilitate the functional
goals of the patient. The foundation for effectiveness of the
orthosis or prosthesis is careful measurement of the body seg­
ment (by casting or by CAD/CAM) and careful modification
of the resulting model for optimal fit. For an individual who
is being fit for his or her initial orthosis or prosthesis, shared
decision making of the rehabilitation team, including the
patient and caregivers, is essential. An orthosis or prosthesis
that is difficult to don or is uncomfortable to wear is more
likely to be found standing in a closet or pushed under a bed
than on the patient for daily use.
REFERENCES
1. Committee on Artificial Limbs. Terminal Research Reports on
Artificial Limbs (Covering the Period from April 1, 1945 through
June 30, 1947). Washington, DC: National Research Council; 1947.
2. Wilson AB. History of amputation surgery and prosthetics. In:
Bowker JH, Michael JW, eds. Atlas of Limb Prosthetics: Surgical,
Prosthetic, and Rehabilitation Principles. 2nd ed. St. Louis: Mosby;
1992:3–15.
3. Wilson AB. Prosthetics and orthotics research in the U.S.A.
International Conference on Prosthetics and Orthotics. Cairo:
S.O.P. Press; 1972:268–273.
4. Rang M, Thompson GH. History of amputations and prosthe­
ses. In: Kostuik JP, Gillespie R, eds. Amputation Surgery and
Rehabilitation: The Toronto Experience. New York: Churchill
Livingstone; 1981:1–12.
5. Eberhart HD, Inman VT, Dec JB, et al. Fundamental Studies of
Human Locomotion and Other Information Relating to the Design
of Artificial Limbs. A Report to the National Research Council.
Berkeley, CA: University of California; 1947.

160
Section I  Building Baseline Knowledge
6. Kay HW. Clinical applications of the Veterans Administration
Prosthetic Center patellar tendon-bearing brace. Artif Limbs.
1971;15(1):46–67.
7. Mooney V, Nickel VL, Harvey JP, et al. Cast-brace treatment for
fractures of the distal part of the femur. J Bone Joint Surg Am.
1970;52A(8):1563–1578.
8. Sarmiento A, Sinclair WF. Tibial and Femoral Fractures—Bracing
Management. Miami: University of Miami; 1972.
9. Committee on Prosthetics Research and Development. Report
of the Seventh Workshop Panel on Lower Extremity Orthoses of
the Subcommittee on Design and Development. Washington, DC:
National Research Council–National Academy of Sciences; 1970.
10. Eberhart HD, McKennon JC. Suction-socket suspension of the
above-knee prosthesis. In: Klopsteg PE, Wilson PD, eds. Human
Limbs and Their Substitutes. New York: McGraw-Hill; 1954.
11. American Society of Testing and Materials (ASTM). Standards.
Philadelphia: ASTM; 2001.
12. International Organization for Standardization (ISO). Prosthetics-
Orthotics. Paramus, NJ: ILI Infodisk; 2000.
13. Shurr DG, Michael JW. Methods, materials, and mechanics.
Prosthetics and Orthotics. 2nd ed. Norwalk, CT: Appleton & Lange;
2002: 2137.
14. O'Flaherty F. Leather. In: American Academy of Orthopaedic
Surgeons, eds. Orthopaedic Appliances Atlas. Ann Arbor, MI: JW
Edwards; 1952:17–28.
15. Redford II JB. Orthotics Etcetera. 3rd ed. Baltimore: Williams &
Wilkins; 1986.
16. Murphy EF, Burnstein AH. Physical properties of materials
including solid mechanics. In: American Academy of Orthopaedic
Surgeons, eds. Atlas of Orthotics: Biomechanical Principles and
Application. 2nd ed. St. Louis: Mosby; 1985:6–33.
17. Compton J, Edelstein JE. New plastics for forming directly on
the patient. Prosthet Orthot Int. 1978;2(1):43–47.
18. Lockard MA. Foot orthoses. Phys Ther. 1988;68(12):1866–1873.
19. Peppard A, O'Donnell M. A review of orthotic plastics. Athletic
Training. 1983;18(1):77–80.
20. Manganon PL. The Principles of materials Selection for
Engineering Design. Prentice Hall; 1999.
21. Levitz SJ, Whiteside LS, Fitzgerald TA. Biomechanical foot ther­
apy. Clin Podiatr Med Surg. 1988;5(3):721–736.
22. Hertzman CA. Use of Plastizote in foot disabilities. Am J Phys
Med. 1973;52(6):289–303.
23. Jopling UH. Observation on the use of Plastizote insoles in
England. Lepr Rev. 1969;40:175–176.
24. Mondl AM, Gardiner J, Bisset J. The use of Plastizote in foot­
wear for leprosy patients. A preliminary report. Lepr Rev.
1969;40(3):177–181.
25. Tuck UH. The use of Plastizote to accommodate foot deformi­
ties in Hansen's disease. Lepr Rev. 1969;40(3):171–173.
26. Spence WR, Shields MN. Insole to reduce shearing forces on the
soles of the feet. Arch Phys Med Rehabil. 1968;49(8):476–479.
27. Campbell G, Newell E, McLure M. Compression testing of
foamed plastics and rubbers for use as orthotic shoe insoles.
Prosthet Orthot Int. 1982;6(1):48–52.
28. Campbell G, McLure M, Newell EN. Compressive behavior after
simulated service conditions of some foamed materials intended
as orthotic shoe insoles. J Rehab Res. 1984;21(2):57–65.
29. Leber C, Evanski PM. A comparison of shoe insole material in
pressure relief. Prosthet Orthot Int. 1986;10(3):135.
30. Pratt DJ, Rees PH, Rodgers C. Assessment of some shock absorb­
ing insoles. Prosthet Orthot Int. 1986;10(1):43.
31. Rome K. Behavior of orthotic materials in chiropody. J Am
Podiatry Assoc. 1990;80(9):471–478.
32. Foto JG, Birke JA. Evaluation of multidensity orthotic materi­
als used in footwear for patients with diabetes. Foot Ankle Int.
1999;20(2):143.
33. Gillespie KA, Dickey JP. Determination of the effectiveness of
materials in attenuating high frequency shock during gait using fil­
ter bank analysis. Clin Biomech (Bristol, Avon). 2003;18(1):50–59.
34. Cinats J, Reid DC, Haddow JB. A biomechanical evaluation of
sorbothane. Clin Orthop Relat Res. 1987;Sep(222):281–288.
35. MacLellan GE, Bybyan B. Management of pain beneath the heel
and Achilles tendonitis with visco-elastic heel insert. Br J Sports
Med. 1981;15(2):117.
36. McCollough III NC. Biomechanical analysis systems for orthotic
prescription. In: American Academy of Orthopaedic Surgeons,
eds. Atlas of Orthotics: Biomechanical Principles and Application.
2nd ed. St. Louis: Mosby; 1985:35–75.
37. Redhead RG. Prescription criteria, fitting, check-out procedures
and walking training for the above-knee amputee. In: Murdoch
G, Donovan RG, eds. Amputation Surgery and Lower Limb
Prosthetics. Oxford: Blackwell Scientific; 1988.
38. Schuster RO. Neutral plantar impression cast: methods and
rationale. J Am Podiatry Assoc. 1976;6(66):422–426.
39. Davies RM, Lawrence RB, Routledge PE, et al. The Rapidform
process for automated thermoplastic production. Prosthet
Orthot Int. 1985;9(1):27–30.
40. Davies RM. Computer aided socket design: the UCL system.
In: Davies RM, ed. Annual Report of the Bioengineering Centre.
Roehampton, England: The Bioengineering Centre; 1986:
9–12.
41. Davis FM. In-office computerized fabrication of custom
foot supports. The AMFIT system. Clin Podiatr Med Surg.
1993;10(3):393–401.

161
Footwear: Foundation for Lower Extremity Orthoses
Jennifer M. Bottomley
The most essential element of clothing in any person's ward­
robe is the shoe. No other article of clothing is designed to fit
so precisely. Continuous pressure from tight shoes can pro­
duce ulceration and deformities. Ill-fitting shoes can create
shear forces that lead to skin breakdown, create and facilitate
toe and foot deformities, and lead to falls.1 Shoes perform
the vital functions of transferring body weight to the floor
during walking and of protecting the wearer from any haz­
ards in the environment. A well-designed shoe is the neces­
sary foundation for many lower extremity orthotics and for
prosthetic alignment and an energy-efficient gait. This chap­
ter discusses the components and characteristics of shoes,
ensuring proper fit, and choosing appropriate footwear for
patients with foot dysfunction and deformity.
COMPONENTS OF A GOOD SHOE
A suitable pair of shoes minimizes stress on all portions of
the feet, provides support, and acts as a shock absorber of
ground reaction forces.2 The basic parts of a shoe are the sole,
upper, heel, and last. Each of these parts is further divided into
­component parts or areas that are required for proper shoe
design (Figure 7-1). Each component is crucial to the prescrip­
tion of appropriate shoes for the person's individual needs.
Sole
The sole protects the plantar surface of the foot. The tradi­
tional sole consists of two pieces of leather sewn together
with a layer of compressible cork between. An additional
layer, the insole, is situated next to the foot in most shoes.
A heavy thick sole protects the foot against walking sur­
face irregularities. The rigidity or stiffness of the sole is also
important. Although it needs to be durable, the sole must not
be so rigid as to interfere with the toe rocker of the metatar­
sophalangeal (MTP) hyperextension during terminal stance
and preswing phases of gait.
Various areas of the sole are identified by location. The
welt is the inside piece of the external sole; the outsole is
the portion that is most external. The area that lies between
the heel and the ball of the shoe, the shank, is commonly fab­
ricated to provide reinforcement and shape using materials
such as spring steel, steel and leatherboard, or wood strips
between the welt and the outsole. The purpose of the shank
is to prevent collapse of the material between the heel and the
ball of the foot and to provide extra support. In most athletic
shoes, the sole is rubber to provide maximal traction. Rubber
soles absorb shock, thereby minimizing heel impact forces.
Upper
The upper of the shoe—divided into the vamp, tongue, and rear
quarters—covers the dorsum of the foot. The vamp extends
from the insole forward. The tongue is an extension of the
vamp in a blucher-style closure, but in the bal-type oxford,
the tongue is separate (Figure 7-2). The blucher-style closure
can be opened slightly more than the bal oxford closure to
allow the foot into the shoe. The toe of the vamp is often cov­
ered with a separate piece of leather called the tip. The rear­
ward line of the tip may be straight or winged. The vamp is
joined to the quarters, which make up the sides and back of
the upper. The two quarters are joined at a back seam. The
design of the shoe dictates the shape and size of the quarters.
For the oxford shoe, the outside quarter is cut lower than the
inside to avoid contact with the malleoli. In the bal oxford, the
back edges of the vamp cover the forward edges of the quarter.
7
LEARNING OBJECTIVES
On completion of this chapter, the reader will be able to:
1. Determine the proper fit of standard footwear on the basis
of necessary function of the foot during gait and the con­
tour and alignment of a patient's foot.
2. Recommend appropriate footwear styles and characteris­
tics for patients with foot deformity and for patients who
wear orthoses or prostheses.
3. Describe the shoe modifications and accommodative
orthoses that can be used to address musculoskeletal prob­
lems affecting the foot and lower limb.
4. Describe the effect of selected problems and deformity of
the forefoot, midfoot, or rearfoot on weight bearing and
efficiency of the gait cycle, and suggest appropriate foot­
wear or orthotic interventions to reduce pain and improve
function.
5. Identify special footwear needs for individuals with arthri­
tis, gout, diabetes, peripheral vascular disease, hemiplegia,
and amputation or congenital deformity of the foot and leg.

162
Section I  Building Baseline Knowledge
The forward edges of the quarters are on the top of the vamp
in the blucher style of shoe.
For individuals wearing orthoses and those with foot defor­
mity, the blucher closure is preferable to the bal-style closure
because of its construction. The blucher closure has a separa­
tion between the distal margins of the lace stays, thus offer­
ing a wide inlet, making the shoes easier to don and doff and
having a readily adjustable circumference. High shoes, which
encase the malleoli, provide additional mediolateral stability.
Heel
The heel is located beneath the outer sole under the ana­
tomical heel. The heel base is usually rigid rubber, plas­
tic, or wood with a resilient plantar surface. As heel height
increases, the ankle range of motion necessary to lower the
forefoot to the floor increases. Weight-bearing pressures
(vertical forces) on the forefoot and hallux also increase in
midstance to late stance.3 The individual with limited ankle
motion may benefit from a compressible heel base to absorb
shock and achieve plantar flexion during the early stance
phase. A broad, low heel maximizes stability and mini­
mizes stress on the metatarsal heads. Most lower extremity
­orthoses and prosthetic feet are designed for a specific heel
height; efficacy of the orthosis or quality of the prosthetic
gait can be significantly compromised if used with shoes
that have higher or lower heels.
Reinforcements
Strategic shoe reinforcements contribute to foot protection.
Toe boxing at the distal vamp shields the toes and prevents
the anterior portion of the vamp from losing its shape. The
toe box can also be increased in depth to protect and accom­
modate any toe deformities. The heel counter reinforces the
quarters to help secure the shoe to the anatomical heel. The
medial counter helps support the medial arch of the shoe,
and the heel counter aids in controlling the rearfoot. The con­
vex shank piece stiffens the sole between the distal border of
the shoe heel and the MTP joints and aids in supporting the
­longitudinal arch.
Lasts
Shoes are constructed over a model of the foot, called a last,
which is styled from wood, plaster, or plastic. Manufacturers
are now converting to computer-aided last designs. Regardless
of the origin of the last, it determines the fit, walking ease,
and appearance of the shoe. Commercial shoes are made over
many different lasts in thousands of size combinations. Most
shoes are made with a medial last, which means that the toe
box is directed inward from the heel (Figure 7-3). Shoes can
also be made from conventional lasts, straight lasts, inflared
or medial lasts, or outflared or lateral lasts.
FASHION VERSUS FUNCTION
A revolution to create comfortable and “healthy” shoes has
occurred within the shoe industry in response to an epidemic
of footwear-related health problems, the result of long-term
wearing of improperly fitting shoes, which accounts for
more than $3 billion annually in surgery-related costs.4,5
Even the most savvy, health-conscious women sometimes
buy shoes for looks, not fit. A survey of 356 women con­
cluded that almost 90% of women wore shoes that were one
to two sizes too small.6 This trend contributes significantly
to the development of bunions, hammertoes, claw toes,
A
B
D
C
F
G
H
I
E
J
FIGURE  7-1  Basic parts of a shoe. The upper is made up of the
quarter (A) and its reinforcing counter (B), which stabilize the rear­
foot within the shoe; the closure (E) and the tongue (J) across the
midfoot; and the shaft (vamp; I) and toe box (H), which enclose
the forefoot. The exterior outsole (F) is often reinforced with a steel
shank (D) and is attached to the upper at the welt (G). The standard
heel (C) is 3⁄4-inch high.
A
B
C
FIGURE 7-2  Three types of shoe closures. A, In the bal oxford style, the tongue is a separate piece
sewn to the vamp and anterior edges of the quarters. B, In the blucher style, the tongue is an extension
of the vamp and can be opened slightly wider. C, For patients with rigid ankle orthoses, fixed defor­
mity, or fragile neuropathic feet, the lace-to-toe (surgical) style may be necessary.

Chapter 7  Footwear: Foundation for Lower Extremity Orthoses
163
­mallet deformities, corns and calluses, and other disabling
foot problems in midlife and later life.7
Enhancing Function
Foot stability is critical to minimizing ankle injury, exces­
sive pronation, and slipping of the heel during the gait cycle.
A well-designed shoe provides a broad heel base, ankle collar,
and close-fitting heel counter. A keystone of a good shoe is its
ability to absorb shock. The construction of and materials used
for the insole, midsole, and outer sole determine the amount of
shock absorption that the shoe will provide.
A good shoe must be flexible and provide stability with each
step. Flexible construction is especially important in the sole
to enhance the toe rocker in late stance phase. The sole should
also provide adequate traction as it contacts the ground, espe­
cially in early stance as body weight is transferred onto the
foot. A coefficient of friction that is sufficient to minimize
slips and near slips is vital. Heel height can create stress on the
forefoot during gait. Heels of more than 11⁄2 inches exponen­
tially increase weight-bearing forces on the metatarsal heads.7
The ability of a shoe to handle moisture is also an impor­
tant consideration. For optimal foot health and comfort, per­
spiration must be wicked away and, at the same time, external
moisture must be kept out.
The upper should be soft and pliable. Modern tanning
techniques can create strong but supple uppers that surround
the feet supportively and protectively without rubbing and
chafing, while allowing the foot to breathe.
Orthotic-Related Function
A molded insole contributes to foot stability, shock absorp­
tion, and a transfer of shear forces away from problem areas.
Orthoses can enhance the function of the shoes. Chapter 8
presents the principles and practices of orthotic prescription
in commonly occurring conditions of the foot.
PROPER FITTING OF A SHOE: “IF THE
SHOE FITS”
The two primary determinants of proper shoe fit are shoe
shape and shoe size. Shoe shape refers to the shape of the
sole and the upper. Proper fit is achieved when shoe shape is
matched to foot shape. Shoe size is determined by arch length,
not by overall foot length.8 The proper shoe size is the one that
accommodates the first metatarsal joint in the widest part of
the shoe. Properly fitting shoes are important in avoiding foot
discomfort and deformity and are absolutely essential in indi­
viduals with arthritis, diabetes, and other foot disorders.
Great variability is found in human foot size and shape.
Mass-produced shoes, however, are formed over fairly stan­
dard lasts that give a shoe its special size and shape. In the well-
fit shoe, the shape determined by the last approximates the
human foot. The design and construction of the shoe should
allow for a roomy toe box; it should be wide enough for normal
toe alignment and be 1⁄2 inch longer than the longest toe. Proper
fit of the forefoot in the shoe can be a critical factor in reduc­
ing the incidence of bunions, hammertoes, and other forefoot
deformities. In general, the shoe should be wide enough to
accommodate the widest part of the forefoot. A tracing of the
foot (standing) should fit within an outline of the shoe bottom.
Proper fit presupposes proper design, shape, and construc­
tion and is fundamentally wedded to availability in widths as
well as lengths. It is important that the clinician cultivate a
consumer mindset that realizes the medical importance of
modifying the old cliché “if the shoe fits, wear it” to “if the
shoe fits, wear it, and if it doesn't, order it in the correct size.”
A
B
C
D
M
L
M
L
M
L
M
L
FIGURE 7-3  The last determines the shape of the shoe. A, In a conventional last, the forefoot is directly
slightly lateral (L) to the midline. B, A straight last is symmetrical around the midline. C, An inflared
last directs the forefoot medially. D, An outflared last directs it more laterally than a conventional last.
M, medial.

164
Section I  Building Baseline Knowledge
Determining Measurements
The average shoe salesperson does not offer to measure the
foot, instead relying on the consumer to know his or her foot
size. However, because foot size changes over time, periodic
measurement of both feet for length and width is important.
Many shoe styles that are available in retail shoe stores do not
appropriately match the shape of an individual's foot. As a
result, comfort and protection are compromised in the name
of “style.” This is especially problematic in the presence of foot
deformity. Hallux valgus is a foot deformity that is aggravated
by wearing shoes too narrow across the metatarsal heads
and triangularly shaped in the toe box. Shoes should be wide
enough to allow the material of the upper that surrounds the
widest region of the forefoot (i.e., the metatarsal heads) to
be compressed at least 1⁄16 inch before bony contact is made.
Likewise, there should be at least a 1⁄2 inch between the tip of
the longest toe and the front of the toe box in weight bearing
(generally the width of the thumb).
In the United States, 12 standard shoe widths are manu­
factured. They range from the very narrow AAAAA to the
very wide EEEE—that is, AAAAA, AAAA, AAA, AA, A, B,
C, D, E, EE, EEE, EEEE. Because most retail stores stock shoes
of midrange widths (A-E), patients with narrow or wide feet
often have difficulty finding shoes of the optimal width.
Standard shoe sizes are available in half-size increments,
from an infant's size 0 to a man's size 16 in U.S. sizes. The dif­
ference in length between half sizes is 1⁄16 inch. Standard shoe-
sizing classifications are made by groups and lasts: infants’
sizes 0 to 2; boys’ sizes 21⁄2 to 6; girls’ sizes 21⁄2 to 9; women's
sizes 3 to 10; and men's sizes 6 to 12. Sizes larger than wom­
en's size 10 and men's size 12 must often be specially ordered.
A U.S. women's shoe size is usually three half sizes smaller
than the corresponding men's size (e.g., women's size 9 is the
same as a men's size 71⁄2).
European and U.K. manufacturers use a different number­
ing system. The comparison of European and U.K. women's
to men's sizes is based on centimeters (e.g., women's size 38
EUR/5 UK is the same as men's size 40 EUR/5 UK). Table 7-1
compares the standard sizes for U.S., European, and U.K. shoe
manufacturers and lists the measures for each size.
Foot Contour
Foot contour changes throughout the life cycle. Aging, preg­
nancy, obesity, and everyday stresses on the foot cause it to
widen. Deformities such as bunions increase the width and
shape of the foot, and splaying of the metatarsal heads creates
a collapse of the transverse arch, further increasing the width
of the forefoot.9 Forefoot height may increase in the pres­
ence of toe deformities. Deformities such as pes planus (foot
flattening) or pes cavus (high arches) change the contour of
the midfoot. The shape of the foot must be considered and
accommodated when an individual is measured for shoes.
Often a “combined last” (where the last in the toe box is dif­
ferent from the rearfoot counter) is required to accommodate
the contour of the foot. The relationship of the forefoot to the
rearfoot is an important consideration in determining if the
shoe shape, provided by the last, corresponds to the shape of
the foot. Shoes with medial, straight, or lateral lasts can be
ordered to best meet patient needs.
Obesity and Edema
The additional mechanical stress of carrying excess weight
takes its toll on the feet, often resulting in problems such as
plantar fasciitis, arthritis and bursitis, heel pain, neuroma,
and gait changes.10 Frey and associates10 found that a weight
gain of as little as 9 lb over a 5-year period increased foot size
by one full size. Obesity has been shown to increase the length
and the width of the foot. The Frey study also revealed that
although women tended to adjust for length increases by pur­
chasing a longer shoe, they rarely increased shoe width. The
net result over the 5-year study period included increased
incidence of calluses, corns, bunions, hammertoes, ingrown
toenails, and neuromas.
Obesity also has an impact on gait patterns. Obese per­
sons demonstrate increased step width, increased ankle dor­
siflexion with reduced plantar flexion, increased Q angles at
the knee, increased hip abduction angles, increased abducted
foot angles, greater out-toeing, a tendency for flat-footed
weight acceptance early in the gait cycle, increased touch­
down angles, more eversion at the subtalar joint, and a faster
maximum eversion velocity. These gait changes may be an
TABLE 7-1  Comparison of Standardized Shoe Sizes
United States
Europe
United Kingdom
Centimeters
WOMEN'S SIZES
3
34
1
20
31⁄2
34.5
1.5
20.5
4
35
2
21
41⁄2
35.5
2.5
21.5
5
36
3
22
51⁄2
36.5
3.5
22.5
6
37
4
23
61⁄2
37.5
4.5
23.5
7
38
5
24
71⁄2
38.5
5.5
24.5
8
39
6
25
81⁄2
39.5
6.5
25.5
9
40
7
26
91⁄2
40.5
7.5
26.5
10
41
8
27
MEN'S SIZES
6
40
5
24
61⁄2
40.5
5.5
24.5
7
41
6
25
71⁄2
41.5
6.5
25.5
8
42
7
26
81⁄2
42.5
7.5
26.5
9
43
8
27
91⁄2
43.5
8.5
27.5
10
44
9
28
101⁄2
44.5
9.5
28.5
11
45
10
29
111⁄2
45.5
10.5
29.5
12
46
11
30

Chapter 7  Footwear: Foundation for Lower Extremity Orthoses
165
attempt to increase stability during gait. The net effect, how­
ever, is an increased incidence of overuse injuries as a result
of everyday activities.10
Proper shoe fitting is essential for preventing secondary
foot problems that stem from ill-fitting shoes. Overweight
individuals should be encouraged to have their feet measured
regularly, particularly if they have had a significant weight
gain. It is often helpful to shop for shoes at the end of the
day, when feet are largest, and the shoe fitting should be done
with the person standing to ensure that 1⁄2 inch is between the
end of the longest toe and the edge of the toe box. The shoes
should be comfortable the moment they are worn.
Fluctuation in foot size in individuals with edema (e.g.,
those with kidney dysfunction or congestive heart fail­
ure or any patient who is taking diuretic medication) cre­
ates a challenge when fitting shoes. The contour of the foot
is constantly changing. For someone with severe edema, a
Thermold (P. W. Minor Shoes, Batavia, N.Y.) Velcro closure
shoe/sandal (Figure  7-4) is recommended to accommo­
date and support the foot and prevent the undue pressures
imposed by a shoe that becomes too small during the course
of the day.
CONSEQUENCES OF THE ILL-FITTING SHOE
The national obsession with beauty has created some not-
so-beautiful feet problems, such as bunions, hammertoes,
and neuromas. These are particular problems for women,
who often select poorly fitting shoes in an attempt to have
the foot appear to be smaller, daintier, and narrower than it
actually is. In Frey and associates’ study,6 90% of women sur­
veyed wore shoes that were too small by one or two width
and length sizes, and 80% of these women had foot problems.
Snow and associates11 report that 90% of 795,000 surgeries
for bunions, hammertoes/claw toes/mallet toes, neuromas,
and Taylor bunions could be directly attributed to wearing
ill-fitting shoes. Foot problems including bunions, lesser toe
deformities, and neuromas are the primary consequences
of wearing ill-fitting shoes. Clearly, many of these problems
would be prevented by habitual use of properly fitting shoes.
SPECIAL CONSIDERATIONS
Feet come in many shapes, sizes, and conditions of health.
The biomechanical and functional characteristics of feet
change over an individual's lifetime and must also be reflected
in shoe choice. An infant's foot must adapt to weight bearing,
especially as walking becomes functional. The foot of a child
continues to adapt as normal growth changes alignment of
pelvis, femur, and tibia. The influence of hormones during
pregnancy also affects the structure and function of the foot.
Finally, the combined influence of the aging process, obesity,
and diseases that are common in later life can create special
footwear needs for older adults.
Pediatric Foot
Many pediatric and lower extremity foot disorders are min­
imally symptomatic and do not require treatment, whereas
others require more aggressive management. An understand­
ing of the natural history of many of these disorders is impor­
tant in establishing the appropriate footwear for toddlers and
children as they begin to walk and run.12–14
In-toeing is a problem caused by positional factors in utero
and during sleep, muscle imbalances due to paralytic dis­
orders, and decreased range of motion in the lower kinetic
chain. It may also be due to metatarsus adductus, internal
tibia torsion, or internal femoral torsion.
Metatarsus adductus is characterized by a bean-shaped
foot that results from adduction of the forefoot. In most chil­
dren (approximately 85%), this disorder resolves itself spon­
taneously.15 If it does not improve over the first 6 to 12 weeks
of life, the treatment of choice is an outflared shoe. The
bones of the foot are soft and can be corrected with position­
ing in the outflared shoe (reverse last) or Bebax shoe (Camp
Healthcare, Jackson, Mich.).
Internal tibial torsion is a twist between the knee and the
ankle. Generally, this torsion disappears by 5 years of age.
Torsion can be exacerbated by abnormal sitting and sleep
postures with the foot turned inward. (Some of the best ath­
letes are in-toers.) The Dennis Browne bar or the counterro­
tation splint is used in combination with a reverse last shoe
to remodel the bones during growth. Persistent severe toeing
created by internal tibial torsion requires a derotational oste­
otomy of the tibia/fibula in the supramalleolar region.
Internal femoral torsion can also be the cause of in-toeing
with a twist between the knee and hip. Neither splints nor
shoes are effective in treatment of torsion. Habitual sitting
in the “W” position (e.g., when a child is watching television
or playing games on the floor) can aggravate the problem.
Children with internal femoral torsion should be encouraged
to sit “X” legged as an alternative.
Out-toeing occurs in children who sleep in the frog posi­
tion and have soft tissue contractures around the hip. This
is usually a hip or a long bone torsion problem and is not
affected by footwear.
FIGURE 7-4  Thermold (P. W. Minor Shoes, Batavia, N.Y.) Velcro
closure shoe/sandal. Adjustable Velcro closures are recommended
to accommodate edematous feet and prevent tissue damage due to
high pressure.

166
Section I  Building Baseline Knowledge
Toe walking can be the result of an in utero shortening
or a congenital shortening of the Achilles tendon but can
also be an early sign of cerebral palsy, muscular dystrophy,
or Charcot-Marie-Tooth disease.15 Until 4 years of age, the
ability to stretch the tendon is well preserved, and conserva­
tive treatment includes stretching, casting, ankle-foot ortho­
ses, and/or a night splint. Z-plasty lengthening is performed
if conservative interventions fail. Shoe prescription objec­
tives follow the same principles as those in the older adult
with Achilles tendinitis (see Achilles Tendinitis, Bursitis, and
Haglund's Deformity).
Flexible flatfoot appears to reflect generalized hereditary
ligamentous laxity.16 Treatment for flatfootedness in chil­
dren has changed over time. Currently, the shoe used to treat
flatfoot is designed to correct heel valgus, support the arch,
and pronate the forefoot in relation to the rearfoot. Forefoot
pronation is achieved by using a lateral shoe wedge com­
bined with a medial heel wedge. A scaphoid pad supports the
arch, and a strong medial counter prevents medial rollover.
A Thomas heel is often used to provide additional support
for the arch.
Calcaneovalgus is a congenital positional deformity. The
heel is in severe valgus, and the foot is dorsiflexed so much
that it rests against the anterolateral aspect of the tibia.
Calcaneovalgus is usually secondary to intrauterine position.
Most cases correct spontaneously. Treatment of the severe
cases includes stretching and serial casting. A few severe
cases, if left untreated, persist into adolescence as pes planus.
An accessory navicular bone is a small ossicle at the medial
tuberosity of the navicular. Individuals with an accessory
navicular bone often complain of pressure and discomfort
when wearing shoes. Often, placement of a prefabricated arch
support in the shoe lifts the arch just enough to minimize
rubbing on the shoe.
Hallux valgus (bunions) is most often the consequence of
rearfoot valgus, leading to varus of the first metatarsal. The
conservative approaches to treating this condition in children
are orthoses and comfortable shoes, with a good heel counter
to maintain the heel in subtalar neutral.
Curly toes involve the congenital shortening of the flexor
tendons. Treated conservatively, flexors are stretched, and a
rocker-like insole is used in the shoe to support the toes in
extension. Shoes must have extra depth with plenty of room
in the toe box.
Shoe prescription for these biomechanical problems of
the foot and lower extremity in childhood is as valuable as
a conservative corrective intervention. Overall, if a child's
foot is developing normally and does not exhibit any signs of
an abnormality, a soft-soled shoe is appropriate.17,18 If some
degree of abnormality exists, a more supportive, rigid shoe is
indicated for toddlers. In general, the stiffer the heel counter,
the more effective the intervention.
The most common prescription shoe for young children
is a straight last shoe. This type of shoe is roomy enough to
accommodate pads or wedges. In addition, a straight last
shoe does not generate any abnormal forces against the
child's foot.
Foot During Pregnancy
During pregnancy, women may experience problems in
lower extremities, including edema, leg cramps, restless legs
syndrome, joint laxity, and low back pain. As a result, foot
pain is a common problem in pregnant women.19 An impor­
tant consideration is the provision of shoes with maximum
shock absorption. Gel-cushioned running shoes are recom­
mended, especially if women continue to jog or walk for exer­
cise. Expectant mothers are also advised to exercise on soft
surfaces to prevent problems caused by repetitive pounding
on unforgiving surfaces.
High-heeled shoes exaggerate the lordotic curve and are
inadvisable during pregnancy. As weight distribution shifts
with advancing pregnancy, especially if edema occurs, many
women choose to wear shoes with laces or a Velcro closure.
Athletic and walking shoes provide good support, excellent
cushioning, and a solid heel counter. If a heel is desired for
special occasions, a 1-inch or lower heeled shoe should be
recommended. Even low but tiny tapered heels cause women
to wobble as they walk.
Many women find that their feet have “grown” during
pregnancy; after having returned to prepregnancy weight and
clothing, their shoes no longer fit. Measurements often reflect
an increase in shoe length of a half to a full size. The stress of
extra body weight coupled with ligamentous laxity can reduce
arch height, adding length to feet. This process is a normal
age-related change in foot structure, associated with wear and
tear of the body over time, which is hastened during preg­
nancy. The hormonally induced tissue laxity of pregnancy
leads to a broader forefoot as the metatarsal heads separate
and the distal transverse arch flattens and to a longer foot as
the longitudinal arch is less efficiently supported by soft tis­
sue structures. For this reason, pregnant women are advised
to wear a larger shoe size, with a square or deeper toe box, or
both, especially if edema is also a problem.
Garbalosa and McClure20 found that almost 80% of the
general population has a forefoot varum deformity. This
foot deformity displaces the center of gravity forward, which
can increase stress on the back during pregnancy. Forefoot
varum deformity produces instability whenever the center
of gravity is moved anteriorly over the forefoot in weight
bearing, forcing the foot into exaggerated pronation.21 The
net effect of the hormonal changes, pregnancy-induced for­
ward displacement of the center of gravity, and the presence
of forefoot varum is increased strain on the axial skeleton
and reduced efficiency of gait. An orthosis to support the
metatarsal heads and medial longitudinal arch, placed in
shoes with good shock absorption ability, can help decrease
foot discomfort and prevent injury to the low back during
pregnancy.
Foot in Later Life
Foot problems are one of the most common complaints of
older adults. The foot is also the most frequently neglected
area of evaluation by most health care practitioners. In a study
of patients who resided in a long-term care facility, 40% did
not own properly fitting shoes. A subsequent survey indicated

Chapter 7  Footwear: Foundation for Lower Extremity Orthoses
167
that the majority of community elders preferred to wear slip­
pers and did not own adequate footwear.22
Gait disorders are a major cause of morbidity and mor­
tality in older adults, significantly contributing to the risk of
disabling injury.23 Gait changes, poor health, and impaired
vision are the major predictors for falls.24 Many older per­
sons attribute their problems with walking to pain or a sense
of unsteadiness, stiffness, dizziness, numbness, weakness, or
impaired proprioception.24
Physical therapists work with patients to maximize their
functional abilities and mobility. Treating foot pain and dys­
function can be a fundamental contributor to becoming
functional in ambulation. As Helfand so eloquently stated,
“Ambulation is many times the key or the catalyst between an
individual retaining dignity and remaining in a normal living
environment or being institutionalized.”25
Gait and foot problems in older adults are associated with
diseases that are common in later life and with the aging pro­
cess itself. Examples of conditions that can compromise gait
and foot function include the residuals of congenital defor­
mities, ventricular enlargement, spinal cord diseases, joint
deformities, muscle contractures, peripheral nerve inju­
ries, peripheral vascular disease, cerebrovascular accidents,
trauma, ulcers, arthritis, diabetes, inactivity, and degenerative
and chronic diseases.23 The anatomical and biomechanical
considerations of podogeriatrics focus on the interrelation­
ships of the rearfoot, midfoot, and forefoot, established by
osseous, muscle, and connective tissue structures. Movement
of one joint influences movement of other joints in the foot
and ankle. Soft tissue structures establish an interdependency
of the foot and ankle to the entire lower limb. As tissues age,
they become stiffer, less compliant, weaker, and more vulner­
able to breakdown.
Foot contour alters with aging; the foot gets wider, and
bunions and splaying occur from collapse of the transverse
arch.26 Forefoot height increases in the presence of toe defor­
mities. Fat pads under the metatarsal joints atrophy and shift
position distally, whereas the calcaneal fat pad atrophies and
shifts laterally. These changes leave bony prominences that
are vulnerable to breakdown.
In the diabetic patient, development of Charcot's joint
(neuropathic arthropathy) is a relatively painless, progres­
sive, and degenerative destruction of the tarsometatarsal or
MTP joints.27–30 With the sensory losses that are common in
diabetes, these joints are subjected to extreme stresses with­
out the benefits of normal protective mechanisms. Capsular
and ligamentous stretching, joint laxity, distention, sublux­
ation, dislocation, cartilage fibrillation, osteochondral frag­
mentation, and fracture occur.31,32 Hyperemia increases the
blood supply, which promotes resorption of bone debris with
resorption of normal bone as well. The foot often fuses in a
deformed rocker bottom shape, vulnerable to pseudoarthro­
sis, instability, abnormal weight-bearing surfaces, ulcerations,
and infections.33,34
The majority of foot problems in geriatric patients can be
managed with proper shoe fitting and minimal shoe modi­
fications. The most inexpensive footwear for this patient
population is running or walking shoes. These are less expen­
sive and fit within a fixed-income budget.35 They provide
good foot support and can be purchased with Velcro straps
for closure if hand function or foot edema is a problem. The
Thermold shoe is also a blessing for all the pathological and
structural deformities with which the older patient must deal.
CHOOSING APPROPRIATE FOOTWEAR
AND SOCKS
A vast and somewhat bewildering variety of “off-the-shelf”
footwear is available to consumers. Many shoes are designed
with certain types of activities in mind. Understanding the
design and construction, as well as ensuring proper fit,
enhances foot health and minimizes the risk of foot dysfunc­
tion, injury, and pain.
Athletic Shoe Gear
Many people jump into fitness activities “feet first” and
develop blisters, calluses, and other foot injuries because of
inappropriate footwear. A well-fit, activity-appropriate ath­
letic shoe enhances enjoyment of the activity by protecting
and supporting the foot and minimizing injury. Athletic shoes
are designed for specific activities. A running shoe is designed
with a high-force heel impact and forward foot movement in
mind; the various shoe models have specific features that are
designed for different surface conditions and distances in
running. Basketball shoes do not provide as much cushioning
as do running shoes but instead focus on foot support dur­
ing quick lateral movement. Aerobic shoes are also designed
for lateral movement but provide more cushioning for the
impact anticipated on the ball of the foot. Shoe soles are also
designed for the surface on which the activity is performed.
Some shoes are manufactured as cross-training shoes so that
they can go from the workout in the gym to jogging but are
not designed for high-mileage runners.
Determining the foot type is important in prescribing
the best shoe. For individuals with a flat, low-arched foot,
a shoe that provides maximum stability to prevent the foot
from rolling in with each step is required. High-arched feet
demand a shoe that is more flexible. “Normal” feet do best
in a shoe that combines the last to accommodate the heel
and the forefoot and that has forefoot flexibility. The size
and shape of the toe box must also be considered. Enough
room should be available in the toe box to prevent blisters,
ulcers, and chafing of the toes. Shoes made from materials
that “breathe” so that perspiration can escape are desirable.
Athletic shoes are best used only for their intended activity
and should be replaced at regular intervals to maximize their
effectiveness.
Most athletic footwear is available in medium widths,
although a few manufacturers provide shoes in several
widths. Children's athletic footwear is available in narrow,
medium, and wide widths. Women's athletic footwear may
be available in AA, B, and D widths. Men's athletic foot­
wear may be available in B, D, EE, and EEE widths. The key
element in proper fit of athletic shoes is comfort from the

168
Section I  Building Baseline Knowledge
moment the shoe is put on, with no break-in period needed.
The shoe should also provide adequate support and shock
absorption for the sport or activity that is being pursued.
Walking Shoes
A well-designed walking shoe provides stable rearfoot con­
trol, ample forefoot room, and a shock absorption heel and
sole. This type of footwear may be specifically designed by
an athletic footwear manufacturer or even by an orthopedic
footwear manufacturer. Walking shoes are available in vari­
ous widths and in several different lasts. Long medial coun­
ters, Thomas heels, and crepe soles can be used to modify this
type of shoe gear to meet specific patient needs.
Dress Shoes
Despite the fashionable preference for shoes with narrow
or pointed toes and slim high heels, the most foot-friendly
dress shoe for women is a rounded-toe Mary Jane style with
boxy heels. A good dress shoe approximates the shape of
the individual's foot and provides flexibility and sufficient
shock absorption. Prerequisites of a good dress shoe include
a roomy toe box, low stable heel, proper width in the ball of
the foot area, flexible outsole with skid-proof bottoms, and
arch support.36
Triangular toe boxes and high heels, no matter how dainty,
are best avoided because they can and do cause deformity.
For a high-heeled shoe to stay on the foot, it must fit closely
around the toes, resulting in no room for anything but the
foot. The foot is virtually unsupported at the distal end of
the shank, and extreme high pressure is present under the
metatarsal heads. Heels higher than 2 inches make any kind
of orthosis ineffectual.37 Because the angle of the foot causes
the heel of the orthosis to lift up, high heels can transform an
orthosis into a catapult. Although orthoses can help relieve
metatarsal and heel pain and provide arch support, they can­
not offer any corrective features in a shoe that is designed so
unnaturally for the human foot.11
Socks
The sock is often overlooked when shoes of any kind are pre­
scribed. Socks can aid in shock absorption, shield the skin
from abrasion by the shoe stitching and lining, and prevent
skin irritation from shoe dyes and synthetic leather materials.
Additionally, clean, freshly laundered socks are integral to a
sanitary foot environment. Unbleached, white cotton socks
are ideal because they lack dyes, are hypoallergenic, and
absorb perspiration readily. Cotton socks also provide ample
toe room, unlike socks that are made from stretchable fabric,
which can crowd the toes.
The size and style of socks also influence foot health. Socks
that are too short crowd the toes; those that are too long wrin­
kle within the shoe, creating potential shear pressure points.
If knee-high socks are worn, the proximal band must not be
unduly restrictive; similarly, the use of circumferential garters
to hold socks can impede circulation to the foot. Any holes
worn into the sock also potentially create shear pressures and
should be discarded. Mended holes in socks, because of the
difference in thickness and materials, can irritate delicate or
insensate soft tissue. An open hole at the toes pinches and
constricts the digits, with excessive friction at the edges of
the hole.
The Thor-lo sock (Thor-lo Inc., Statesville, N.C.) is spe­
cially designed to support and cushion the insensitive foot or
athletic/military foot that is exposed to repetitive frictional
forces. Use of these specially designed socks not only reduces
the frictional shearing forces but also significantly decreases
vertical ground reaction pressure forces, preventing blister­
ing and ulceration.38–43 Extra high-density padding functions
as a natural fat pad, reducing the deteriorating effects of
shearing forces and the pressure and friction in the toe area.
The Thor-lo concept of stockings is beneficial for patients
with insensitive feet. It has also been used for individuals
involved in aerobic exercise, baseball, basketball, cycling,
golf, hiking, trekking and climbing, skiing, tennis, walking,
and running.
PRESCRIPTION FOOTWEAR, CUSTOM-
MOLDED SHOES, ACCOMMODATIVE MOLDED
ORTHOSES, AND SHOE MODIFICATIONS
Alteration of foot function and alignment can be accom­
plished with one or more of the following strategies: foot
orthoses of the appropriate materials, prescription shoes,
and modifications of shoes themselves.44–46 These strategies
are used to relieve pain and improve balance and function
during standing and locomotion. These alternatives are
indicated when a transfer of forces from sensitive to pres­
sure-tolerant areas is needed to reduce friction, shock, and
shear forces; to modify weight transfer patterns; to correct
flexible foot deformities; to accommodate for fixed foot
deformities; and to limit motion in painful, inflamed, or
unstable joints.
When special protective or prescription footwear is being
considered, the functional objectives must be clearly stated so
that the appropriate specific prescription can be developed.
Careful examination of the foot helps the clinician iden­
tify pathology or mechanical factors, or both, that must be
addressed and choose the appropriate materials and footwear
styles to meet the patient's specific needs.
Moldable Leathers
Thermold is an example of prescription footwear that can
be used to protect feet that are vulnerable due to vascular
insufficiency, neuropathy, or deformity (Figure  7-5). It is
a cross-linked, closed-cell polyethylene foam laminated to
the leather upper of the footwear that can be heat molded
directly to the foot. This makes modification for foot defor­
mity easily managed and far less expensive than custom
molding. Thermold shoes are also available in extra-depth
styles, with a removable 1⁄4-inch insole. Extra-depth shoes
enable adequate room for custom-made insoles or ortho­
ses to become an intricate adjunct to the footwear. In some
instances, the Thermold can be used as an alternative to the
custom-molded footwear.

Chapter 7  Footwear: Foundation for Lower Extremity Orthoses
169
Custom-Molded Shoes
Some foot problems cannot be accommodated in conven­
tional footwear, and the best solution is custom-molded
footwear. This footwear is molded directly over a plaster
reproduction of the foot rather than a standard last. Special
modifications, such as toe fillers, Plastazote (Zoteforms, Inc.,
Hackettstown, N.J.), rocker bars, and elevations, can be added
during manufacturing to meet the specific requirements of
each foot. Because of this process, custom-molded shoes are
made to conform to the foot shape in all respects (Figure 7-6).
Custom orthopedic shoes represent the ultimate combination
of function and aesthetics. Incorporating biomechanics and
craftsmanship, shoes can redistribute weight, restrict joint
motion, facilitate ambulation, and decrease the probability of
neuropathic ulceration.47,48
Plastazote Shoe or Sandal
For patients with insensitive or ulcerated feet, a “healing
sandal” or Plastazote shoe is often prescribed. This custom
shoe is fabricated using a plaster cast of the individual's foot
for construction.49 Temporary protective footwear, such as a
Plastazote boot or shoe or a healing sandal, is often used dur­
ing neuropathic ulcer wound healing to allow for ambulation
without pressure on the healing area, especially for patients
who are unable to walk or noncompliant with non–weight-
bearing ambulation.
Shoe Modifications
Various shoe modifications can be used to address functional
and anatomical deformities of the foot and leg. Clearly stated
objectives, based on careful evaluation, ensure that the appro­
priate shoe modifications are chosen.
Lifts for Leg-Length Discrepancy
For patients with leg-length discrepancy of 3⁄8 inch or more, a
full-length external lift can be mounted to the sole of the shoe
on the shorter limb to equalize leg length and reduce proxi­
mal stresses at the hips and spine. If the length difference is
less than 3⁄8 inch, the discrepancy can usually be accommo­
dated with an orthotic heel wedge worn inside the shoe. If the
discrepancy is a result of a unilateral equinus deformity, a heel
wedge can be attached to the external surface of the shoe. Leg
length discrepancy is a common result of a hip fracture, con­
genital anomaly, or biomechanical imbalance such as pelvic
rotation, hip anteversion or retroversion, or unilateral foot
pronation. The level of the pelvis and absolute and relative
measures of leg length should be part of a comprehensive gait
evaluation.
Heel Wedging
Wedging is used to alter lines of stress to facilitate a more nor­
mal gait pattern. The most effective wedges range from 1⁄8 to 1⁄4
inches in thickness at their apex. Larger wedges tend to cause
the foot to slide away from the wedge toward the opposite
side of the shoe, drastically reducing the effectiveness of the
modification. Wedging is useful for children with a rotational
problem, such as tibial torsion. In adults, wedges are used for
accommodation in conditions such as a fixed valgus defor­
mity of the calcaneus (Figure 7-7).
A medial heel wedge is used when flexible valgus of the
calcaneus is present (Figure 7-8A). As the wedge elevates the
FIGURE 7-5  Thermold shoes (P. W. Minor Shoes, Batavia, N.Y.).
These shoes allow for easy modification to accommodate foot
deformities.
FIGURE 7-6  Examples of custom-molded shoes. These shoes are
prescribed when foot deformities are too severe for accommodation
in a conventional shoe.
FIGURE  7-7  A heel wedge provides elevation of the heel for
­equinus deformity.

170
Section I  Building Baseline Knowledge
medial heel, a resultant varus tilt acts on the calcaneus, pre­
venting excessive pronation of the foot. A lateral heel wedge
is used when flexible varus of the calcaneus is present (see
Figure  7-8B). Elevation of the lateral heel decreases the
medial drive on floor contact at heel strike, tipping the calca­
neus into valgus. A full heel wedge is sometimes used in the
presence of fixed or functional equinus deformity. The goal
of wedging is to obtain a subtalar neutral position during the
stance phase of gait.
Sole Wedging
Wedging can also be used to modify midfoot and forefoot
positions. A medial sole wedge produces an inversion effect on
the forefoot. This wedge is positioned along the medial aspect
of the footwear, from a point just proximal of the first meta­
tarsal head to the midline of the footwear (see Figure 7-8C).
Conversely, a lateral sole wedge creates an eversion effect at
the forefoot. This wedge is placed proximal to the fifth meta­
tarsal head to the midline of the footwear. The apex of this
wedge is the fifth metatarsal head (see Figure 7-8D).
A Barton wedge (see Figure 7-8E) is used in the presence
of severe, flexible pronation deformities, such as those seen
in pes planus, when control of the midfoot is the goal. The
Barton wedge, usually made with 3⁄16-inch leather, extends
along the medial side of the foot to the midtarsal joint and
tapers laterally just anterior to the cuboid bone. It provides
support to the navicular and helps invert the calcaneus. It is
used when it is necessary to shift body weight laterally. When
a Barton wedge is used, the shoe must have a firm medial
counter. The Barton wedge can be incorporated in an inter­
nally placed lateral heel wedge for patients with fixed calca­
neal varus or clubfoot deformity. Because an internal wedge
is closer to the target deformity, it creates a positive force of
greater magnitude than is possible with the external Barton
wedge. Instead of tilting the footgear, the wedge tilts the
­calcaneus into the desired position.
Steel Spring
The steel spring, an external shoe modification, is a piece of
flexible metal that is 1⁄16 inch in depth and 1 inch in width,
extending along the length of the footwear. It is usually placed
between the insole and outsole of the shoe to restrict flexion of
the sole. The need to enhance the strength of the shoe shank is
often required to control the foot when lower extremity brac­
ing is necessary. A steel spring is frequently helpful in assist­
ing an individual who has hemiplegia with forward propulsion
during the vertical pathway of the foot, from initial contact
through midstance and into push-off/terminal stance.
M
M
M
M
M
A
B
C
D
E
FIGURE 7-8  Examples of heel and sole wedge modifications. A medial (M) heel wedge (A) is used
when flexible valgus of the calcaneus is present; a lateral heel wedge (B) is used for flexible varus of
the calcaneus. Medial sole wedges (C) create an inversion effect of the forefoot, whereas lateral sole
wedges (D) create an eversion effect. A Barton wedge (E) supports the navicular bone and helps invert
the calcaneus, shifting the body weight laterally.

Chapter 7  Footwear: Foundation for Lower Extremity Orthoses
171
Metatarsal Bars and Rocker Bottoms
A metatarsal bar is a block of material (usually stacked pieces
of leather or rubber) that is attached to the sole of the shoe. Its
placement proximal to the metatarsal heads significantly reduces
pressure at the metatarsal heads during the push-off phase of
the gait cycle.50 The curved distal edge of the metatarsal bar is
designed to follow the curve of the metatarsal heads. It is com­
monly used to adapt shoes worn by patients with transmetatarsal
amputations, fixed arthritic deformities, diabetes, forefoot defor­
mities such as hallux rigidus, and neuromas. The placement of
a metatarsal bar or rocker facilitates push-off by simulating for­
ward propulsion in the absence of metatarsal flexibility.
Rocker bottoms are made of either lightweight crepe or
leather (Figure 7-9). These modifications are flush with the
heel and toe, in an arch with an apex of 1⁄2 to 5⁄8 inch. The rocker
bar redistributes body forces over the entire plantar surface of
the foot while in weight bearing. It facilitates a smooth roll
during the stance phase of gait, while reducing sheer stress and
trauma to the midfoot and forefoot. It is often used to modify
shoes worn by patients with partial foot amputations, arthri­
tis, and diabetes. It is also used for patients who have any lower
extremity orthosis that limits forward progression of the tibia
over the foot and toes during mid- and late-stance phases. For
patients with diabetes, a rigid rocker sole (a steel-spring heel-
to-toe with the toes extended and a rocking axis near the cen­
ter of the foot) can be used to help distribute body weight and
compel knee flexion at toe-off, reducing the length of stride
and sheer stress on the metatarsal heads.
Thomas Heels
The Thomas heel is designed to improve foot balance and
relieve excessive pressure on the shank portion of the foot­
wear. Applied as either a lateral or a medial flare of the heel, its
goal is to increase stability during gait by assimilating subtalar
neutral. A laterally flared heel is used with a rearfoot varus to
decrease the incidence of inversion injuries. A medially flared
heel is used with a rearfoot valgus to decrease the incidence
of eversion injuries (Figure 7-10). For instance, a medial flare
from the heel to the sustentaculum tali prevents excessive
pronation of the foot during gait.
Offset Heels and Shoe Counters
The offset heel is a modification used to help correct valgus
or varus deformities. It offers a broad support base, especially
at the superior surface of the heel, where the broad buildup
against the shoe's counter provides reinforcement either
medially or laterally. A heel counter is an extension along
the medial or lateral borders of the shoe from the heel to
the proximal border of the fifth or the first metatarsal head.
This shoe modification strengthens the shank portion of the
footwear for better control of the hind foot. The heel counter
is often used in combination with the appropriate Thomas
heel. A counter can also be placed medially or laterally in
the midfoot region. A patient whose gait exhibits excessive
pronation, such as is common in rheumatoid arthritis, may
require a firm medial counter to prevent the shoe from col­
lapsing medially and to assist in realigning the foot into a
neutral position.
FIGURE 7-9  Examples of rocker bottom soles. A metatarsal bar (A) prevents undue pressure at the
metatarsal heads during push-off in late stance. A rigid leather rocker sole (B) or an extended crepe
rocker bar (C) redistributes body weight over the entire plantar surface, facilitating a smoother and
more normal gait pattern while reducing stress and trauma in the forefoot.
L
M
L
M
A
B
FIGURE 7-10  Examples of Thomas heels. A, A medial (M) flared
heel provides a broader base of support and prevents eversion of the
ankle. B, A lateral (L) flared heel prevents inversion of the ankle.

172
Section I  Building Baseline Knowledge
Attachments for Orthoses
For some patients with neuromuscular dysfunction (e.g.,
hemiplegia, paraplegia, multiple sclerosis), a traditional metal
­double-upright lower-extremity orthosis can be prescribed. If so,
the shoe must be modified: a U-shaped orthotic bracket (stir­
rup) is attached to the shoe by means of three copper rivets, one
on the heel and two in the shank. The metal is riveted through
the outsole to the insole. To accomplish this, the heel is removed
and the plate of the stirrup is attached. The groove is then cut
through the heel, and the heel is reattached. The appropriate
orthotic ankle joint is then attached to uprights of the stirrup.
Shoe Stretching
Shoes with leather uppers can be stretched almost one full
width. Although a shoe cannot be truly lengthened, it can
be made to feel longer with a toe box stretcher device that
looks like the shape of the foot and is inserted into the shoe
to expand it (Figure 7-11). After the leather is moistened or
softened, this device effectively raises and slightly rounds
the toe box. Frequently, the pressure of a flat toe box on the
toes is more problematic than the length of the shoe. Specific
points in the shoe can be softened and expanded by plac­
ing an “expansion knob” on the toe-box stretcher or using a
ball-and-socket device. Site-specific stretching is particularly
helpful for patients with toe deformities such as hallux valgus,
hammertoe, mallet toe, claw toe, overlapping toes, and Taylor
bunion deformity.
Blowout Patches and Gussets
Patients with foot deformities who prefer conventional
shoes to Thermold shoes may find temporary pain relief
if a blowout patch or gusset is applied to their shoe. The
shoe leather around the area of deformity is cut away and
replaced with a softer blowout patch or gusset of moleskin,
soft leather, or suede.
FOOTWEAR FOR COMMON FOOT
DEFORMITIES AND PROBLEMS
Conservative management of common forefoot, midfoot, and
rearfoot deformities often involves modification of shoes or
prescription footwear, or both. Specific footwear strategies for
several common foot problems are described in the following
section.
Problems in the Forefoot
The most common footwear variation used for abnormalities
in the forefoot is a high toe box. High toe boxes are avail­
able in various footgear, including athletic sneakers, comfort
shoes, Thermolds, and prescription footwear. To accommo­
date forefoot deformity optimally, the maximum height of the
abnormal toes must be measured in a weight-bearing posi­
tion. Tables of manufactured shoes by toe box space are avail­
able to guide the clinician in recommending shoes that most
closely match patient needs.51
Metatarsalgia
Metatarsalgia is pain around the metatarsal heads that results
from compression of the plantar digital nerve as it courses
between the metatarsal heads. Excessive weight bearing with
atrophy of the metatarsal fat pad can result in irritation of
the nerves and potentially lead to development of a neuroma.
The three major objectives in shoe prescription for patients
with metatarsalgia are to (1) transfer pressure from painful,
sensitive areas to more pressure-tolerant areas, (2) reduce
friction by stabilizing the MTP joint, and (3) stabilize the
rearfoot and midfoot to reduce pressure on the metatarsal
heads.52 Characteristics of the shoe that will accomplish these
goals include wide width to reduce pressure on the transverse
metatarsal arch, long fitting to eliminate plantar-flexed MTP
joints, cushion soles to enhance shock absorption, and a high
toe box to allow forefoot flexion and extension. Additionally,
the shoe should include a long medial counter to stabilize the
rearfoot, a lower heel to minimize pressure at the metatarsal
heads, and preferably thermoldable leather to accommodate
deformities. Shoe modifications often include a transverse
FIGURE 7-11  Tools that are used to stretch leather shoes. Stretching
often provides adequate accommodation for deformities in conven­
tional shoes. The toe box stretcher (right) can increase width by
one size. The ball-and-socket device (left) is used to stretch specific
points that correspond to the forefoot and toe deformity.

Chapter 7  Footwear: Foundation for Lower Extremity Orthoses
173
metatarsal bar to redistribute pressure from metatarsal heads
to metatarsal shafts and shorten stride and a rocker sole to
reduce motion of painful joints.
Sesamoiditis
Sesamoiditis is an inflammation around the sesamoid bones under
the first metatarsal head. It often results from a loss of soft tissue
padding under the first metatarsal head and from toe deformities
such as hallux valgus and hallux rigidus. The objective of shoe pre­
scription for patients with sesamoiditis is to redistribute weight-
bearing forces from the first MTP joint and its sesamoids to the
long medial arch and shafts of the lesser metatarsals. A transverse
metatarsal bar is used to redistribute pressure from metatarsal
heads to metatarsal shafts and to shorten stride. A rocker sole can
be used to reduce motion of the painful hallux joint.
Morton's Syndrome
With repetitive irritation of the plantar digital nerve between
the first and second metatarsal heads, a neuroma is likely to
develop.53 This condition is known as Morton's syndrome. The
three major objectives in shoe prescription for patients with
Morton's syndrome are to (1) redistribute weight from the lesser
metatarsals (especially the second and third) to the proximal
phalanx of the hallux, (2) stabilize the rearfoot by maintain­
ing subtalar joint neutral, and (3) accommodate forefoot varus
as well as a possibly dorsiflexed first metatarsal. Shoe prescrip­
tion includes a long medial counter for rearfoot support and
stability; a straight or flared last to accommodate foot shape; a
high, wide toe box to reduce compression across the transverse
metatarsal arch; a large enough shoe size to accommodate the
long second toe; and a Thomas heel or wedge sole to support
the medial longitudinal arch. A medial heel and medial sole
wedge may be necessary when symptoms are severe.
Morton's (Interdigital) Neuroma
Overstretching of the digital nerves in extreme toe extension
at the proximal phalanx can also result in the development of
a neuroma. Two objectives should be considered for patients
with Morton's neuroma. First, the patient must obtain relief
from the pain and burning, especially in the third interspace
of the MTP joint. Second, compression of the digital nerve as
it passes between the heads of the third and fourth metatarsals
needs to be reduced. To achieve these goals, the shoe should
be wide enough to eliminate transverse compression and have
enough length to reduce plantar flexion of the MTP joints.
A long medial counter can help reduce pronation; a cushioned
sole increases shock absorption, and a low heel unloads pres­
sure on the metatarsals. Elastic laces may be helpful in allow­
ing expansion of the forefoot. Shoe modifications for Morton's
neuroma might include a metatarsal bar to elevate the meta­
tarsals and redistribute weight, or a metatarsal rocker bar to
immobilize the metatarsals, or a combination of both.
Metatarsalgia of the Fifth Metatarsophalangeal Joint
Like the metatarsalgia described previously, metatarsalgia
of the fifth MTP joint results in plantar digital nerve irrita­
tion at the interdigital space of the fourth and fifth metatarsal
heads. When metatarsalgia of the fifth MTP joint is present,
the goals of intervention are to redistribute weight forces to
the fifth metatarsal shaft and to provide a broad base of sup­
port along the lateral border of the foot. The optimal shoe
has a last with enough lateral flare to accommodate the lat­
eral aspect of the foot and fifth metatarsal shaft, a firm lateral
counter, and a firm leather or rubber sole. Possible shoe mod­
ifications include a lateral heel and sole flare ending proximal
to the fifth metatarsal head to provide a broader base of sup­
port. Lateral heel and sole wedges may be useful for patients
with flexible feet.
Hallux Rigidus (Limitus)
Degenerative joint disease of the first MTP joint causes pain,
loss of mobility, and eventually fusion of the joint. Osteophyte
formation on the dorsal aspects of the metatarsal head and
base of the proximal phalanx can be quite painful and result in
a loss of extension. For patients with hallux rigidus or limitus,
the goals are to limit motion of the hallux and first MTP joint
and to reduce pressure on the dorsal and plantar aspects of
the hallux and first MTP joint.54 To accomplish this, the shoe
should have a high and wide toe box and Thermold or soft
leather uppers. When significant deformity is present, a steel
shank from heel to phalanx of the hallux and a rigid rocker
sole with compensating heel elevation may be necessary.
Hallux Valgus (Bunions)
A prominent bony formation on the medial aspect of the
first MTP joint can result from lateral deviation of the hal­
lux and from foot pronation.55 This deformity is often asso­
ciated with long-term wearing of shoes with a triangular toe
box. Five objectives should be considered in the prescription
of shoes for patients with hallux valgus: (1) to reduce friction
and pressure to the first MTP joint, (2) to eliminate abnormal
pressure from narrow-fitting shoes, (3) to reduce pronation of
the foot from heel strike to midstance, (4) to correct eversion,
and (5) to relieve posterior tibial tendon and ligamentous
strain. Patients with hallux valgus benefit from shoes with
high, wide toe boxes and Thermold or soft leather uppers.
A combined last with increased last width in the toe box and
a smaller heel for better control of the subtalar joint may also
be indicated. Additionally, the choice of a shoe that is longer
and wider helps to accommodate deformity; a lower heel to
reduce forefoot pressure and a reinforced medial counter help
prevent pronation.
Hammertoes, Claw Toes, and Mallet Toes
Hammertoe deformity is characterized by hyperextension of
the MTP joint, flexion of the proximal interphalangeal (PIP)
joint, and extension of the distal interphalangeal (DIP) joint.
This results in high load during weight bearing at the plantar
metatarsal heads and at the plantar surface of the distal pha­
lanx. Claw toe deformity features hyperflexion of the PIP and
DIP joints, although the MTP joint can be hyperextended or
hyperflexed. Mallet toe deformity results from hyperexten­
sion of the MTP joint, flexion of the PIP, and a neutral posi­
tion of the DIP, so that weight bearing is on the tip of the

174
Section I  Building Baseline Knowledge
distal phalanx. Deformities of the lesser toes can be problem­
atic, especially for patients with compromised circulation and
neuropathy. For these individuals, there are two major foot­
wear goals: (1) to transfer pressure away from the metatar­
sal heads, the PIP joints, and the distal phalanx joints, and
(2) to encourage flexion of the MTP joints and extension of
the PIP joints.56 Patients with lesser toe deformities should
wear shoes with a high, wide toe box made of Thermold or
soft leather to reduce the likelihood of microtrauma over the
bony prominences. The shoe should also be long enough to
allow flexion of MTP joints and extension of PIP joints rather
than cramping the toes. Finally, a soft cushion outsole and
low heel further reduce pressure on the metatarsal heads.
Commonly used shoe modifications for lesser toe deformi­
ties include metatarsal bars to reduce pressure to metatarsal
heads and shift weight bearing to metatarsal shafts, as well as
a rocker bar or rocker sole to accommodate rollover on fixed
deformity.
Problems in the Midfoot
Shoe prescriptions or modifications, or both, are also helpful
in managing midfoot dysfunction and deformity. The most
commonly encountered problems include pes planus, pes
equinus, pes cavus, and plantar fasciitis.
Pes Planus
Pes planus is pronation of the midfoot that results in a fail­
ure of the foot to supinate during midstance. The longitudi­
nal arch flattens, causing a splaying of the forefoot and lateral
deviation of the metatarsals. This deformity can be either
flexible or fixed (rigid).
For patients with a flexible pes planus, the goals of inter­
vention are to reduce pronation from heel strike to mid­
stance, correct eversion, relieve tension on the posterior tibial
tendonitis, and relieve ligamentous strain. To do these things,
the shoe should offer a long medial heel counter, a Thomas
heel (medial extension) or a firm wedge sole, and a straight
last. A custom shoe is recommended for severe cases. Shoe
modifications may include a medial heel wedge to correct
eversion and reduce pronation or a medial heel and sole flare
in extreme cases.
Because of the fixed nature of a rigid pes planus, the goals
are somewhat different: to relieve ligamentous strain, to
relieve arch pain, and to correct eversion of the foot. The opti­
mal shoe should offer a broad shank (extra wide midfoot), a
straight last, and a long medial counter. Additionally, a wedge
sole is applied to reduce the load on the metatarsal heads, sta­
bilize the intertarsal joint, and provide a dorsiflexion assist.
Pes Equinus
In pes equinus, the plantar flexor muscles and Achilles ten­
don are tightened, which limits dorsiflexion of the ankle and
results in a plantar flexion deformity. For patients with a flex­
ible pes equinus, the footwear prescribed attempts to reduce
ankle plantar flexion, reduce the load on the metatarsal heads,
and stabilize the subtalar joint. This can be accomplished in
a shoe with a low heel. A rocker bottom can be applied to the
sole to provide a dorsiflexion assist and further reduce load
on the metatarsal heads.
When the pes equinus deformity is rigid or fixed, the goals
of footwear intervention change. Instead of trying to reduce
plantar flexion, a posterior platform supports the rearfoot
from heel strike to midstance and mimics the dorsiflexion
needed at toe-off. It is important to contain the entire foot
in the shoe, reducing the load on the metatarsal heads. For
patients with unilateral deformity, it is also important to
equalize the relative leg length difference between the normal
foot and the equinus foot through all phases of gait. Shoe pre­
scription for patients with a fixed equinus deformity includes
a Cuban (elevated) heel to provide a platform and deep quar­
ter or high-top shoes. If modifications are necessary, they
might include posterior heel elevation on the equinus side,
as well as on the contralateral limb, to facilitate swing of the
involved limb and reduce pelvic obliquity.
Pes Cavus
Pes cavus is an exaggerated longitudinal arch that can lead
to a plantar flexed forefoot with retraction of the toes and
severe weight-bearing stresses on the metatarsal heads and
heel. Patients with pes cavus benefit from shoes that pro­
vide a broad platform for stability; reduce loading at the
heels, lateral borders, and metatarsal heads; and accommo­
date the deformed foot within the shoe. The shoe should
also have a firm heel counter to maintain rearfoot stabil­
ity and a modified, curved last to accommodate foot shape.
Custom-molded shoes are recommended in severe cases.
Possible shoe modifications for patients with pes cavus
include a lateral flare to provide a platform for greater sta­
bility, a cushion sole to absorb shock on the heel and meta­
tarsal heads, and a metatarsal bar to shift weight from the
metatarsal heads.
Plantar Fasciitis
Plantar fasciitis is inflammation of the plantar fascia at its
insertion to the medial aspect of the calcaneus. This inflam­
matory process can lead to the development of ­calcification
at that insertion, commonly referred to as a heel spur.
Plantar fasciitis is often a consequence of loss of the lon­
gitudinal arch in conditions such as pes planus or of undo
stresses created in the forefoot with tightness of the gastroc­
nemius and soleus muscles or an elevated longitudinal arch.
To reduce the painful signs and symptoms of plantar fasci­
itis, the goals of intervention are to transfer weight-bearing
pressure from painful to more tolerant areas, to reduce ten­
sion on the plantar fascia and Achilles tendon, to control
pronation from heel strike to midstance, and to maintain
the subtalar joint in a neutral position. The shoe prescribed
for plantar fasciitis has a long medial heel counter to limit
heel valgus, a high heel to reduce tension on the plantar fas­
cia and Achilles tendon, and adequate length to minimize
compression and promote supination from midstance to
toe-off. The types of shoe modifications that may be useful
include a posterior heel elevation to reduce tension on the
plantar fascia and Achilles tendon.

Chapter 7  Footwear: Foundation for Lower Extremity Orthoses
175
Problems in the Rearfoot
The most common dysfunctions and deformities of the rear­
foot that can be addressed by footwear prescription or modi­
fication include arthrodesis, Achilles tendinitis or bursitis,
and Haglund's deformity (pump bump).
Arthrodesis
Arthrodesis is a loss of mobility at the ankle mortise, the
junction of the talus with the tibia and fibula. This defor­
mity prevents motion at the ankle in all planes and alters
progression through the stance phase of gait, and it may
also compromise limb clearance in swing phase. When
arthrodesis of the ankle is present, the major objectives
are to provide effective shock absorption and controlled
lowering of the forefoot at loading response, to improve
comfort and efficiency of push-off, and to accommodate
any shortening or residual equinus. Shoes that address the
problems of arthrodesis have a reinforced counter and may
have a medial or a lateral flared heel (or a combination
of both) to provide greater stability. Some patients benefit
from a high-top shoe as well. Modifications that protect
the foot and facilitate a more normal gait pattern include
application of a cushioned heel to absorb shock and simu­
late plantar flexion after heel strike and a rocker sole to
mimic the dorsiflexion needed in the late stance phase.
Achilles Tendinitis, Bursitis, and Haglund's Deformity
Undue stresses of the Achilles tendon, direct pressure of a
too-short shoe, and/or tightness of the gastrocnemius and
soleus muscles can result in tendinitis or bursitis. Haglund's
deformity is an osseous formation at the insertion of the
Achilles tendon at the calcaneus. The goals of shoe prescrip­
tion for patients with Achilles tendinitis, bursitis, and/or
Haglund's deformity (pump bump) are similar: (1) to reduce
tension on the Achilles tendon, (2) to provide dorsiflexion
assist at heel strike and at toe-off, (3) to reduce abnormal
pronation, and (4) to reduce pressure and friction (shear) at
the insertion of the calcaneus. Patients with these problems
require a slightly higher heel to reduce dorsiflexion, a long
medial counter to limit subtalar motion, a longer shoe size to
reduce compression pressure, and a backless shoe to prevent
irritation of the pump bump. The types of shoe modifica­
tions that may be helpful include a posterior heel elevation to
reduce tension on the Achilles tendon or a foam-filled pos­
terior heel counter.
DIAGNOSIS-RELATED CONSIDERATIONS
IN SHOE PRESCRIPTION
Prescription footwear and shoe modifications are also
extremely useful tools to protect joints, prevent skin prob­
lems, and enhance normal function of patients who are
coping with arthritis and gout or diabetes and peripheral vas­
cular disease. Adaptations to footwear may also be helpful for
patients with hemiplegia, partial foot amputations, or con­
genital deformities.
Arthritis
Arthritis, whether degenerative, rheumatoid, or traumatic,
leads to destruction of joints. In working with patients with
foot arthritis, the goals of intervention are to prevent or limit
abnormal motion, accommodate for arthritic deformities, and
cushion impact loading and reduce microtrauma within the
joint.57 A reinforced counter can help limit subtalar motion; a
high-top design shoe can also help limit ankle motion. Extra-
depth shoes may be needed to accommodate deformities of
the midfoot and forefoot. Thermoldable leather is preferable
if deformities need further accommodation. The application
of a rocker bottom helps to improve push-off by shorten­
ing the distance between the heel and the MTP joint. It also
reduces the total ankle motion required for push-off. Shock-
absorbing accommodative orthoses can be placed inside the
shoe, and a cushion heel can be added to absorb even more
force at heel strike and limit ankle and subtalar motion.58
A flared heel can reduce medial and lateral movement at the
subtalar joint.
Gout
For patients with gout, the treatment objectives are similar
to those for patients with arthritis—preventing or limiting
motion of painful or inflamed joints, accommodating foot
deformities, and cushioning the impact of loading on the
involved joints. A reinforced counter to limit subtalar motion
or a high-top design to limit overall ankle motion should be
considered. An extra-depth shoe of thermoldable leather is
best able to accommodate deformities without creating pain
and discomfort over sensitive joints. A rocker bottom can be
applied to assist push-off, prevent pedal joint movement, and
reduce ankle motion required for push-off. Shock-absorbing
accommodative orthoses and cushion heels provide even
more comfort and protection of inflamed joints during gait.
Diabetes
The loss of protective sensation in patients with diabetic neu­
ropathy creates significant vulnerability to injury from repet­
itive microtrauma. Protection of the plantar surface of the
diabetic foot from microtrauma is of paramount importance.
Patients with diabetic neuropathy often have significant weak­
ness of intrinsic muscles. Forefoot deformities develop, includ­
ing claw toes, which are susceptible to breakdown in areas of
excessive shoe pressures. The risk of nonhealing, infection, and
subsequent amputation is quite high; prevention is the most
effective treatment strategy. Total-contact full-foot orthoses
using soft, shock-absorbing materials helps distribute weight-
bearing pressures over the entire plantar surface of the foot
away from the vulnerable bony prominences. A Thermold
leather shoe is recommended for the insensitive diabetic foot.
Peripheral Vascular Disease
Because the ability to heal is compromised in patients with
peripheral vascular disease, any irritation or ulceration
exponentially increases the risk of infection and ­subsequent
amputation. Here, too, prevention of skin breakdown and
protection of the vulnerable foot are the primary goals.

176
Section I  Building Baseline Knowledge
The ability to fit and protect the foot effectively is further chal­
lenged by fluctuating edema. A Thermold sandal with Velcro
closure is often recommended for patients with peripheral
vascular disease-related edema as a safe and effective alter­
native to standard shoes. If edema is not a problem, a soft
Thermold shoe protects the plantar surface of the foot from
repetitive pressures and accommodates deformities that are
at risk for shoe pressure–related trauma. Because hypersen­
sitivity is often a problem with circulatory pathologies in the
lower extremities, a shoe that cushions the foot may be help­
ful. Elastic shoelaces allow expansion of the shoe for patients
with minimal edema-related fluctuations in foot size.
Hemiplegia
The patient with hemiplegia after a cerebrovascular accident
(e.g., stroke, may have inadequate or excessive tone of the
lower extremity. Many of these patients need orthotic inter­
vention to control the foot and ankle in some or all phases of
gait, to accommodate for any fixed deformities and to cush­
ion impact loading at initial contact. Footwear is selected to
enhance orthotic function or, in some instances, to directly
impact mild dysfunction. A reinforced heel counter helps
to limit subtalar motion and stabilize the foot on heel strike.
A  flared heel or high-top shoe may be recommended to
enhance foot placement and stance stability. A rigid shoe
shank may be required for some types of lower extrem­
ity orthoses. In the presence of an equinus deformity, a heel
lift on the shoe provides total contact during weight bearing
and facilitates stability. In severe deformities of the ankle, a
­custom-molded shoe may be the only alternative.
The most common ankle-foot orthoses used in hemiple­
gia tend to increase shoe length, width, and depth by a half to
a whole size. Often the insole can be replaced with an insert
foundation, to garner a little more room for the orthosis within
the shoe. Extra-depth shoes are particularly helpful for patients
who are faced with difficulty in donning their orthosis and
shoe because of upper extremity dysfunction in hemiplegia.
Amputation and Congenital Deformity
The foot that is shortened surgically or is congenitally deformed
is a management challenge because the weight-bearing sur­
face is reduced or altered, increasing the likelihood of tissue
breakdown with repeated loading in gait. The type of protec­
tive footwear used can range from an over-the-counter extra-
depth shoe for a mild deformity to a custom-molded shoe for a
severe deformity. When the feet are of unequal size, it is more
difficult to fit them without buying two pairs of shoes or having
custom footwear made. If the difference between the feet is no
more than one size in length, the larger size can be used with
toe padding for the shorter deformed or amputated foot or
with an orthosis to accommodate the deformity (Figure 7-12).
Frequently, the shorter foot is also wider and must be accom­
modated by the appropriate orthosis custom molded to the
shoe. A toe filler prevents the shortened foot from sliding
within the shoe during gait but also increases the risk of skin
breakdown. It is crucial that the first MTP joint be aligned with
the “toe break” point in the shoe. If the foot falls posterior to
the toe break, stress is concentrated at the distal end of the foot,
increasing the chance of pressure imposition by the “filler.”
READING THE WEAR ON SHOES
For the clinician who is faced with decisions about modi­
fying, repairing, or replacing footwear, examination of pat­
terns of wear and erosion provides important information.
Deterioration of the shoe itself impairs tactile sensibility
and position sense judgment.59 Shoes that have outlasted
their purpose often create abnormal forces and shearing that
increase the risk of repetitive microtrauma to the skin and
joints of the foot and ankle. Analysis of the wear and erosion
of the shoe is a prescriptive tool in advising, prescribing, and
modifying a shoe to fit individual needs.
FIGURE 7-12  A toe filler can be used on a foot that has been short­
ened by amputation or congenital deformity.
CASE EXAMPLE 1
A Patient with Diabetes Who Is Homeless and Has a Neuropathic Foot Ulcer
J. H. is a 71-year-old homeless, Hispanic man with a 22-year
history of type 2 diabetes mellitus treated with gliben­
clamide 2.5 mg three times daily. He presents with a large
ulcer (6.552 cm2) of the plantar surface of the midfoot with
significant arch deformity of the right foot, subsequent to
an episode of Charcot arthropathy several years ago. J. H.
reports that the ulcer has been present for more than 1 year.
He has complications resulting from diabetes, including
retinopathy, peripheral neuropathy, and history of numer­
ous neuropathic ulcerations involving both feet. He also

Chapter 7  Footwear: Foundation for Lower Extremity Orthoses
177
has a 24-year history of arterial hypertension and a docu­
mented myocardial infarction. He is currently managed
with ­angiotensin-converting enzyme inhibitors and calcium
antagonists. It is unclear how regularly he has taken his
medications, although they are available at no cost through
the shelter's clinic. J. H. has been homeless for 7 years.
J. H. is referred to the health clinic at the homeless shelter
for diabetic and hypertensive assessment and conservative
treatment of the foot ulceration.
Questions to Consider
• What tests and measures might the foot clinic team use
to assess current status and changes in J. H.'s neuropathic
wound, the deformity of his feet, the circulation and sen­
sory status of his limbs, and his functional status and
gait? What is the evidence of reliability and validity of
these measures?
• What does the team need to understand about his cur­
rent health status and diabetic control? How will they
gather this information?
• What are the immediate needs, in terms of footwear,
for J. H.? How might his needs change over time as his
wound heals?
• Given his current health status and lifestyle, what factors
will likely affect (both positively and negatively) clinical
decision making about footwear, wound care, diabetic
management, and follow-up care? How might the team
prioritize goals and possible interventions?
• How would the team assess efficacy of their interventions?
Initial Results
Satisfactory metabolic control and blood pressure values are
achieved during the initial week of medical management at
the shelter clinic. J. H. is referred to Boston City Hospital
(BCH) for a series of tests and measures on an outpatient
basis. Although J. H. is found to have bilateral diabetic ret­
inopathy (fundus oculi), there is no evidence of diabetic
nephropathy. Echocardiogram evidences a left ventricular
hypertrophy with a normal regional kinesis and an ejection
fraction of 50%.
Electromyography shows normal conduction velocity and
slight abnormalities of sensory action potentials in the nerves
of both lower extremities. An elevated threshold of 40 V to
biothesiometer and a partial loss of sensitivity (nine of nine
areas tested are insensitive bilaterally) to Semmes-Weinstein
5.07 monofilament are recorded. The transcutaneous oxygen
tension is 30 mm Hg at the dorsum of the involved foot (right)
and 15 mm Hg at the perilesional site. In the ulcerated limb, the
ankle-brachial index measured with Doppler technique is 0.8.
Duplex scanning shows widespread atheromasic lesions in the
carotids and in the lower limb arteries without hemodynami­
cally significant stenoses and no significant alterations in the
venous district of the lower limbs.
J. H.'s ulcer on the right foot appears superficial and
is graded as a Wagner grade II ulcer. The ulcer is cov­
ered by a fibrinous exudate with keratotic margins. The
­microbiological cultures are negative. A surgical debride­
ment is performed at BCH and the patient/client is sent
back to the shelter with instructions for local treatment
before and after daily sharps debridement consisting of the
daily application of sterile paraffin gauze and for “evaluation
and conservative treatment” by a physical therapist.
Questions to Consider
• How might the team interpret the results of the tests per­
formed at BCH? How will this information influence or
inform wound care and recommendations for footwear
for this gentleman?
• What additional information will the physical therapist
and foot care clinic team need to gather?
• What are the primary goals of physical therapy/foot care
intervention? What is the prognosis and anticipated out­
come? What is the anticipated duration of this episode of
care? How frequently might J. H. receive care?
• What interventions would be most appropriate to
address the goals of wound healing and prevention of
future recurrence of neuropathic ulcers?
Physical Therapy Examination, Evaluation
and Intervention
J. H. is examined at the shelter by a physical therapist on
the Foot Clinic Team. He arrives at the clinic ambulating
independently, without any assistive devices. The ulcer on
the plantar surface of his midfoot measures 6.552 cm2, in the
Charcot joint deformity region of the right foot. The ulcer
is determined to be secondary to repetitive trauma to this
region in shoes that had a large hole in the midsection of
the sole.
A total contact cast is applied. Selective padding of the cast
includes foam padding over the toes and an ulcerated area of
the foot; felt pads over the malleoli and navicular prominence;
and cotton cast padding around the proximal and anterior
lower leg, heel, sides, and dorsum of the foot. A rubber heel
mount is applied to the cast for ambulation. Fiberglass cast­
ing material is used to decrease the effects of the elements
(weather) on a plaster cast in this homeless individual who
spends much time outdoors. The cast is also bifurcated to
allow high galvanic electrical stimulation to be used as a local
treatment modality to the wound and to provide access for
daily debridement, application of dressings, and monitoring
for secondary lesions. The cast is secured using Velcro strap­
ping. The patient is allowed to walk freely and is highly com­
pliant, wearing the cast continuously.
The ulcer responds favorably to a combination of peri­
odic surgical debridement, local wound care and daily sharps
debridement, a modified total contact casting protocol, and
high galvanic electrical stimulation. After 6 weeks, the ulcer
is completely closed and J. H.'s condition remains stable. He
is subsequently fitted with a total contact foot orthosis bilat­
erally and provided with a pair of Reebok walking sneakers
with an extra width to accommodate the Charcot foot defor­
mity bilaterally.
(Continued)

178
Section I  Building Baseline Knowledge
SUMMARY
The shoe is an essential interface between the foot and
the ground. It protects the foot from trauma and supports
the structures of the foot as an individual walks, runs, and
changes direction. Fashionable footwear, especially for
women, often compromises, rather than enhances, foot
function. Foot function and footwear needs have a devel­
opmental aspect as well; an understanding of how the
foot changes over the life span and of the special needs of
children, pregnant women, and older adults is essential.
Knowledge about the components of shoes and their vari­
ations, the criteria for proper fitting, and the relationship
between shoe design and activity-related demands is an
important tool for clinical practice. Physical therapists are
often called on to recommend footwear for patients with
special needs. A baseline knowledge of shoe characteristics
and modifications for certain types of deformities or diag­
noses enhances this ability.
REFERENCES
1. Finlay OE. Footwear management in the elderly care pro­
gramme. Physiotherapy. 1986;72(4):171–178.
2. Fuller EA. A review of the biomechanics of shoes. Clin Podiatr
Med Surg. 1994;11(2):241–258.
With proper intervention and attention to J. H.'s social
situation, it is determined that the prognosis for preventing
recurrence of neuropathic foot ulcer wound is good and that
he can be integrated into appropriate home, community,
and work environments within the context of his disabil­
ity. J. H. is placed in a permanent shelter-housing residence
and assumes part-time employment as a guide at the Boston
Museum of Science.
Discussion
For individuals with neuropathic wounds, total contact
casting allows ambulation with protection from exter­
nal stress and trauma. In addition, because the cast is well
molded and minimal padding is applied, pressure is distrib­
uted evenly and maintained as long as the cast is worn. This
total-contact cast also counteracts lymphatic congestion,
which compromises the healing process. For J. H., the cast
was bifurcated to allow for daily wound care while provid­
ing consistent pressure relief and foot protection.
The major objectives of treatment after J. H.'s diabetic
neuropathic wound healed were to protect the plantar sur­
face from repetitive microtrauma and accommodate defor­
mities that could be traumatized by excessive shoe pressures,
which could result in ulceration and subsequent injury.
A total-contact, full-foot orthosis using soft shock-absorbing
materials helps distribute weight-bearing pressures over the
entire plantar surface of the foot away from the vulnerable
bony prominences. A Thermold leather shoe or good walk­
ing sneaker is recommended for the insensitive diabetic
foot.
Accommodative devices are insoles that are placed in
shoes to balance the feet, allowing pressures to be evenly
distributed and permitting support and shock absorption of
the foot. An orthosis, in contrast, supports and also controls
the foot by neutralizing pronatory forces. Following wound
healing, a total-contact orthosis (Plastazote with a layer of
3⁄8-inch PPT) was fabricated for J. H. and placed in a pair of
extra-depth Reebok walking shoes.
Accommodating shoe gear should be used by patients
with diabetes, and walking barefooted should not be permit­
ted. The shoe's upper should be soft, so as not to irritate any
prominence or developing deformity. The accommodative
insole that is used should be adaptable to changes as well.
A combination of an expanded polyethylene such as
Plastazote, which can be heat molded to provide total con­
tact, mounted on a shock-absorbing material such as PPT,
or covered with a neoprene, such as Spenco, which is soft
and retains its shape, makes an excellent accommodative
insole. This type of accommodative orthosis protects the
foot from trauma to prominent areas and redistributes the
forces to provide even weight bearing through total contact
upon the plantar surface (Figure 7-13). When accommoda­
tive orthoses are used, the shoe must have adequate depth
to accommodate it. Extra-depth shoes such as Thermold
shoes or extra-depth sneakers allow not only the room
needed for the accommodative insole but also modification
of the upper through heat molding to accommodate lesser
toe deformities. A rigid-sole rocker-bottom shoe might also
be recommended to reduce pressures under the metatarsal
heads during push-off. The apex of the rocker is positioned
just proximal to the metatarsal heads, allowing for the shoe
itself to provide forward propulsion of the foot.
FIGURE  7-13  An example of an accommodative orthosis for a
patient with diabetic neuropathy and Charcot deformity of the left
midfoot. Note the “cutout” to reduce weight-bearing pressure on
the most prominent area of bony deformity and the use of materials
to “fill” space around the deformity and distribute weight-bearing
pressures over the entire plantar surface of the foot.

Chapter 7  Footwear: Foundation for Lower Extremity Orthoses
179
3. Mandato MG, Nester E. The effects of heel height on forefoot
peak pressure. J Am Podiatr Med Assoc. 1999;89(2):75–80.
4. Black E, Black E. Comfort shoes: the long overdue revolution.
Biomechanics. 1995;2(10):27–33.
5. Frey C. If the shoe fits…. Biomechanics. 1995;2(4):26–28.
6. Frey C, Thompson F, Smith J, et  al. American Orthopaedic
Foot and Ankle Society Women's Shoe Survey. Foot Ankle.
1993;14(2):78–81.
7. Coughlin MJ. Lesser toe abnormalities. Oregon Health Science
University. Instr Course Lect. 2003;52:421–444.
8. Janisse DJ. The art and science of fitting shoes. Foot Ankle.
1992;13(5):257–262.
9. Herman HH, Bottomley JB. Anatomical and biomechanical con­
siderations of the elder foot. Top Geriatr Rehabil. 1992;7(3):1–13.
10. Frey C, Chan C, Carrasco N. Obesity: do weight gains lead to
lower extremity pain? Biomechanics. 1996;3(1):30–35.
11. Snow RE, Williams KR, Holmes GB. The effects of wearing
high heeled shoes on pedal pressures in women. Foot Ankle.
1992;13(2):85–92.
12. Sass P, Hassan G. Lower extremity abnormalities in children.
Am Fam Physician. 2003;68(3):417–419.
13. Charrette M. Foot care: do children need corrective footwear?
Dynamic Chiropract. 2003;21(12):28–33.
14. Hein NM. [Inserts and shoes for foot deformities]. Orthopade.
2003;32(2):119–132.
15. Shapiro S. Pediatrics: a reasoned approach to common lower
limb disorders. Biomechanics. 1995;2(5):18–21.
16. Rao UB, Joseph B. The influence of footwear on the preva­
lence of flat foot: a survey of 2300 children. J Bone Joint Surg.
1992;74(4):630–631.
17. Valmassy RL. Pediatric biomechanics. Podiatry Today. 1989;
May:86–92.
18. Valmassy RL. The use of gait plates for in-toed and out-toed
deformities. Clin Podiatr Med Surg. 1994;11(2):211–217.
19. Black E, Cooke Anastasi S. Pregnancy and the lower extremities.
Biomechanics. 1995;2(4):22–25, 68–69.
20. Garbalosa JC, McClure MH. The frontal plane relationship of the
forefoot to the rearfoot in an asymptomatic population. J Sports
Phys Ther. 1994;20(4):200–206.
21. Rothbart BA, Hansen KH, Yerratt MK. Resolving chronic
low back pain: the foot connection. Am J Podiatry Med.
1995;5(3):84–90.
22. Karpman R. Geriatric prefab. Biomechanics. 1995;2(5):53–58.
23. Sudarsky L, Ronthal M. Gait disorders among elderly patients.
Arch Neurol. 1993;40(2):740–743.
24. Hough JC, McHenry MP, Kammer LM. Gait disorders in the
elderly. Assoc Prescription Footwear. 1987;35(6):191–196.
25. Helfand AE. Common foot problems in the aged and rehabil­
itative management. In: Williams TF, ed. Rehabilitation in the
Aging. New York: Raven; 1984:291–303.
26. Edelstein JE. Foot care for the aging. Phys Ther. 1988;
68(12):1882–1886.
27. Pinzur MS. Charcot's foot. Foot Ankle Clin. 2000;5(4):897–912.
28. Pinzur MS, Shields N, Trepman E, et  al. Current prac­
tice patterns in the treatment of Charcot foot. Foot Ankle Int.
2000;21(11):916–920.
29. Frykerg RG, Kozak GP. The diabetic Charcot foot. In: Kozak GP,
Hoar CS, Rowbotham JL, et al., eds. Management of Diabetic
Foot Problems. Philadelphia: Saunders; 1984:103–112.
30. Frykerg RG. Podiatric problems in diabetes. In: Kozak GP, Hoar
CS, Rowbotham JL, et  al., eds. Management of Diabetic Foot
Problems. Philadelphia: Saunders; 1984:45–67.
31. Prior T, Gardiner A, Thomas A, Maitland P. Footwear
requirements of patients with diabetes mellitus. Diabet Foot.
2000;3(1):24–28.
32. Ramuglia VJ, Palmarozzo PM, Rzonca EC. Biomechanical con­
cepts in the treatment of ulcers in the diabetic foot. Clin Podiatr
Med Surg. 1988;5(3):613–626.
33. Bailey TS, Yu HM, Rayfield EJ. Patterns of foot examination in a
diabetes clinic. Am J Med. 1985;78(3):371–374.
34. Pinzur MS. Benchmark analysis of diabetic patients with
neuropathic (Charcot) foot deformity. Foot Ankle Int.
1999;20(9):564–567.
35. Bottomley JB, Herman H. Making simple, inexpensive changes
for the management of foot problems in the aged. Top Geriatr
Rehabil. 1992;7(3):62–77.
36. Seale KS. Women and their shoes: unrealistic expectations?
American College of Podiatry. Instr Course Lect. 1995;44:
379–384.
37. Corrigan JP, Moore DP, Stephens MM. Effect of heel height on
forefoot loading. Foot Ankle. 1993;14(3):148–152.
38. Herring KM, Richie DH. Friction blisters and sock fiber com­
position: a double-blind study. J Am Podiatr Med Assoc.
1990;80(2):3–7.
39. Richie DH, Herring KM. Friction blisters and sock construc­
tion. Presented at the annual meeting of the American Academy
of Podiatric Sports Medicine, Miami, May 29, 1990.
40. Herring KM, Richie DH. Friction blisters and sock fiber com­
position: a single-blind study. Part 2. Presented at 75th annual
meeting of the American Podiatric Medical Association, Las
Vegas, August 15, 1990.
41. Murray HJ, Veves A, Young MJ, et  al. Role of experimental
socks in the care of the high-risk diabetic foot. Diabetes Care.
1993;16(8):1190–1192.
42. Veves A, Masson E, Fernando D, Boulton AJM. Use of exper­
imental padded hosiery to reduce abnormal foot pressures in
diabetic neuropathy. Diabetes Care. 1989;12(9):16–19.
43. Veves A, Masson E, Fernando D, Boulton AJM. Studies of exper­
imental hosiery in diabetic neuropathic patients with high foot
pressures. Diabet Med. 1990;7(3):324–326.
44. Lord M, Hosein R. Pressure redistribution by molded inserts in
diabetic footwear. J Rehabil Res Dev. 1994;31(3):214–222.
45. Shrader JA. Nonsurgical management of the foot and ankle
affected by rheumatoid arthritis. J Orthop Sports Phys Ther.
1999;29(12):703–717.
46. Egan M, Brosseau L, Farmer M, et al. Splints and orthosis for
treating rheumatoid arthritis. Cochrane Database Syst Rev.
2003;(1):CD004018.
47. White J. Custom shoe therapy. Current concepts, designs, and
special considerations. Clin Podiatr Med Surg. 1994;11(2):
259–270.
48. Reiber GE, Smith DG, Wallace C, et  al. Effect of therapeutic
footwear on foot reulceration in patients with diabetes: a ran­
domized controlled trial. JAMA. 2002;287(19):2552–2558.
49. Breuer U. Diabetic patient's compliance with bespoke foot­
wear after healing of neuropathic foot ulcers. Diabetes Metab.
1994;20(4):415–419.
50. Brown D, Wertsch JJ, Harris GF, et al. The effect of rocker soles
on plantar pressure. Arch Phys Med Rehabil. 2004;85(1):81–86.
51. Kaye RA. The extra-depth toe box: a rational approach. Foot
Ankle Int. 1994;15(3):146–150.
52. Kelly A, Winson I. Use of ready made insoles in the treatment
of lesser metatarsalgia: a prospective randomized controlled
­clinical trial. Foot Ankle Int. 1998;19(4):217–220.

180
Section I  Building Baseline Knowledge
53. Childs SG. Diagnosis and treatment of interdigital perineuronal
fibroma (a.k.a. Morton's syndrome). Orthop Nurs. 2002;21(6):32–34.
54. Shrader JA, Siegel KL. Non-operative management of functional
hallux limitus in a patient with rheumatoid arthritis. Phys Ther.
2003;83(10):831–844.
55. Caselli MA. Foot deformities: biomechanical and pathome­
chanical changes associated with aging. Clin Podiatr Med Surg.
2003;20(3):487–509.
56. Hurwitz S. Hammer toe in adults: recognition and clinical man­
agement. J Musculoskel Med. 1999;16(8):460–465.
57. Michelson J, Easley M, Wigley FM, Hellmann D. Foot and
ankle problems in rheumatoid arthritis. Foot Ankle Int.
1994;15(11):608–613.
58. Li CY, Imaishi K, Shiba SJ, et al. Biomechanical evaluation of
foot pressure and loading force during gait in rheumatoid
arthritic patients with and without foot orthosis. Kurume Med J.
2000;47(3):211–217.
59. Robbins S, Waked E, McClaran J. Proprioception and ­stability:
foot position awareness as a function of age and footwear.
Age Ageing. 1995;24(1):67–72.

HISTORY OF THE FUNCTIONAL FOOT
ORTHOSIS
The use of foot orthoses as an effective treatment tool for bio­
mechanical dysfunction of the feet evolved during the twen­
tieth century and continues to be the subject of research and
technology. Early on, foot orthoses were used to redistribute
plantar surface foot forces to alleviate discomfort in pressure-
sensitive areas of the foot. Little consideration was given to
the specific foot abnormality that led to the pathological
condition.1 In the early 1900s metal foot braces began to be
used to control motion at specific joints of the foot and pre­
vent pathological conditions.2 These devices, although func­
tional, were often not well tolerated because of the rigidity
of the materials and the mismatch between brace design and
foot pathokinesiology. In 1948, Schreber and Weineman first
identified forefoot invertus (varus) and evertus (valgus) as pri­
mary foot deformities that required correction by an orthosis.3
In the 1960s, Merton Root developed neutral impression
casting techniques, positive cast modifications, and post­
ing (mechanical correction) techniques.4 The standards that
Root established have enhanced orthotic comfort and func­
tion. Since then, functional foot orthosis use has increased
considerably to address lower limb muscle activation pathol­
ogy of the mechanics of the foot and ankle in musculoskeletal
disorders and neurological disorders.5–11
TRIPLANAR STRUCTURE OF THE FOOT
The foot is a complex of bones interconnected by a series of
multiplanar articulations supported by soft tissue structures.
It is subdivided into three functional components: the rear­
foot, the midfoot, and the forefoot.
Several important articulations of the foot (talocrural,
subtalar, midtarsal, first and fifth rays) are triplanar; the axis
of rotation in these joints is not perpendicular to any of the
cardinal planes (sagittal, horizontal, frontal) of the human
body. As a result, motion about triplanar joints leads to simul­
taneous movement in all three of these cardinal planes.4 The
amount of motion evident in any single plane is related to
the pitch (inclination) of the triplanar axis from the respective
181
II
Orthoses in Rehabilitation
Foot Orthoses
Roberta Nole, Donald S. Kowalsky, Juan C. Garbalosa,
Elicia Pollard, and John Thompson
8
LEARNING OBJECTIVES
On completion of this chapter, the reader will be able to do
the following:
1. Describe the major anatomical structures of the foot as
well as the basic biomechanical principles associated with
these structures.
2. Describe effects of extrinsic and intrinsic deformities and
of abnormal pronation on the function of the foot during
the various phases of gait.
3. Explain strategies used to examine and evaluate intrinsic
foot deformities.
4. Describe abnormal pronation and the pathological condi­
tions that contribute to abnormal pronation in gait.
5. Describe components of a foot orthosis, goals of orthotic
intervention, and specific purposes of the most common
orthotic interventions.
6. Discuss controversy related to traditional orthotic theory.
7. Review literature related to the efficacy of foot orthoses for
the management of common disorders.

182
Section II  Orthoses in Rehabilitation
cardinal plane. Triplanar motion occurs in three-dimensional
space; the breakdown of triplanar motion into its three
constituent cardinal plane movements is artificial.
Because motion about a triplanar axis is three dimen­
sional, motion occurs simultaneously in the three cardinal
planes. Blocking any one component of triplanar motion in
a single cardinal plane prevents movement in the other two
planes as well. This “all-or-nothing” rule is the premise for
orthotic posting or wedging.4 Theoretically, the addition of a
post or wedge to an orthosis blocks the frontal plane compo­
nent of triplanar motion, which in turn blocks or limits the
triplanar motion of pronation. The design principles of foot
orthoses are founded on knowledge of the functional anatomy
of the foot.
Talocrural Joint
The talocrural joint (TCJ) (articulation between tibia, fibula,
and talus, connecting the foot to the lower leg) has a triplanar
axis of rotation. In neutral position, the TCJ axis passes through
the tips of the medial and lateral malleoli, pitched 10 degrees
from the transverse plane and 20 to 30 degrees from the fron­
tal plane (Figure 8-1).12–14 Although sagittal plane plantarflex­
ion and dorsiflexion are primary motions at this joint, the slight
inclination of the TCJ axis of rotation leads to concomitant
transverse and frontal plane motion. During plantarflexion, the
foot adducts and inverts; with dorsiflexion it abducts and everts.
Normal range of motion (ROM) of the TCJ is between 12 and
20 degrees of dorsiflexion and 50 and 56 degrees of plantarflex­
ion.15 The medial (deltoid) and lateral collateral ligaments stabi­
lize and limit motion that occurs at the TCJ.16
Rearfoot
The osseous structures of the rearfoot are the calcaneus (infe­
rior) and the talus (superior) (Figure 8-2). The articulation
between the calcaneus and talus is the subtalar joint (STJ).
Three joint surfaces are present in this articulation: posterior,
anterior, and middle. The posterior joint surface has a con­
cave talar and convex calcaneal portion, whereas the anterior
and middle joint surfaces have convex talar and concave cal­
caneal arrangements. This structurally based articular geom­
etry, along with the interosseous talocalcaneal ligament, limits
the amount and type of motion occurring at the STJ.17,18 The
medial and lateral collateral ligaments and the posterior and
lateral talocalcaneal ligaments also offer support to the STJ.19
At the STJ, the triplanar axis of rotation is oriented in an
anterosuperior to posteroinferior direction, pitched approx­
imately 42 degrees from the transverse plane, 48 degrees
from the frontal plane, and 16 degrees from the sagittal plane
(see Figure 8-2). The location of the STJ axis in the human
foot varies greatly. Manter20 reported that the inclination
from the transverse and sagittal planes varies from 29 degrees
to 47 degrees and from 8 degrees to 24 degrees, respectively.
The triplanar motions at the STJ are supination and
pronation. Supination of the weight-bearing foot leads to
dorsiflexion and abduction of the talus with simultaneous
inversion of the calcaneus. Pronation of the weight-bearing
foot results in plantarflexion and adduction of the talus
TCJ axis
FIGURE 8-1  Posterior view of the osseous components and axis of
the talocrural joint. The osseous components of the talocrural joint are
the tibia medially and superiorly, the fibula laterally, and the talus infe­
riorly. The axis of the joint passes in a posterolateral to anteromedial
direction through the tips of the lateral and medial malleoli. (Courtesy
Juan C. Garbalosa, University of Hartford, West Hartford, Conn.)
A
B
STJ axis
STJ axis
FIGURE 8-2  Superior (A) and lateral (B) views of the osseous struc­
tures in the rearfoot: the superior talus and inferior calcaneus. Also
pictured is the triplanar axis of the subtalar joint. Note the inclina­
tion of the axis from all three cardinal planes of the body. (Courtesy
Juan C. Garbalosa, University of Hartford, West Hartford, Conn.)

Chapter 8  Foot Orthoses
183
and eversion of the calcaneus.4 Because of the variability in
location of the axis of rotation of the STJ, the component
motions of supination and pronation vary as well. As the
axis becomes more perpendicular to a particular cardinal
plane, the motion occurring in that plane becomes more
pronounced, whereas the other motions become less prom­
inent.21,22 This variability affects coupled motion between
the joints of the foot and the lower leg. During pronation
and supination of the rearfoot, the tibia and fibula rotate
internally and externally in the transverse plane.4,23,24 An
increase in the frontal plane motion of the rearfoot could
cause a simultaneous increase in the transverse plane motion
of the lower leg.
Midfoot
The midfoot is composed of two bones: the cuboid and the
navicular. The talonavicular and calcaneocuboid articula­
tions between the midfoot and rearfoot form an important
composite joint: the midtarsal joint (MTJ) or transverse tar­
sal joint. The articular surfaces of the talonavicular joint are
convex-concave, whereas the surfaces of the calcaneocuboid
joint are sellar shaped.13,20 MTJ movement is supported and
restricted by the bifurcate, short and long plantar, and plan­
tar calcaneonavicular (spring) ligaments. The short and long
plantar ligaments and the plantar calcaneonavicular liga­
ments also support the longitudinal and transverse plantar
arches of the foot.25
Because the MTJ is a composite joint, motion occurs
about two separate triplanar joint axes: a longitudinal and
an oblique axis (Figure 8-3). Movement of the forefoot about
each joint axis can occur independently of the other. Manter20
reported that the longitudinal axis is inclined superiorly 15
degrees from the transverse plane and medially 9 degrees
from the sagittal plane, whereas the oblique axis is pitched
superiorly 52 degrees from the transverse plane and medially
57 degrees from the sagittal plane. The predominant motion
about the longitudinal axis is frontal plane inversion and
eversion. Because of the slight deviation of the longitudinal
axis from the three cardinal planes, small amounts of forefoot
plantarflexion and dorsiflexion and adduction and abduction
occur during inversion and eversion. Plantarflexion and dor­
siflexion and abduction and adduction are the predominant
movements around the oblique MTJ axis, with little concomi­
tant inversion and eversion.4,18
These two joint axes produce the combined motion of
supination and pronation of the MTJ. During supination
and pronation, the forefoot inverts and everts about the lon­
gitudinal axis. The motion around the oblique axis is plan­
tarflexion with adduction and dorsiflexion with abduction.
The amount of motion possible at these MTJ axes is deter­
mined by the position of the STJ. In STJ supination, the two
joint axes are nearly perpendicular so that MTJ mobility is
restricted. This mechanism helps convert the forefoot into
a rigid structure for propulsion during the push-off phase
of gait (from heel rise through toe-off).20,26 When the STJ is
pronated, the joint axes are more parallel, allowing a greater
degree of MTJ mobility.
Forefoot
The forefoot includes all structures distal to the navicular and
cuboid bones; it is subdivided into five rays and toes. The
first through third rays consist of a cuneiform and its asso­
ciated metatarsal bone; the fourth and fifth rays consist only
of a metatarsal. The tarsometatarsal joints, the primary joints
of the ray complexes, have two opposing planar surfaces.4,25
The hallux, or first toe, has two bones (a proximal and distal
phalanx) and two corresponding joints (metatarsophalangeal
[MTP] and interphalangeal [IP]). The lesser toes have three
bones (proximal, middle, and distal phalanges) and three
associated joints. The proximal articular surfaces of the MTP
and IP joints are convex, and the distal articular surface is con­
cave.4 Numerous soft tissue structures support these joints.27,28
Although each ray has its own axis of motion, the first
and fifth rays are of particular interest. The triplanar axes
of rotation of these two joints are nearly perpendicular. The
axis of the first ray is pitched at a 45-degree angle from the
sagittal and frontal planes; the primary motions possible are
plantarflexion with eversion and dorsiflexion with inversion.
Oblique MTJ axis
Oblique MTJ axis
Longitudinal
MTJ axis
A
B
FIGURE  8-3  A superior (A) and lateral (B) view of the osseous
components of the midtarsal joint (MTJ). The anterior portion of
the MTJ is composed of the navicular and cuboid bones, whereas the
posterior portion is composed of the calcaneus and talus. The two
axes of the MTJ, the oblique and longitudinal axes, are also depicted.
Like the subtalar joing, both axes of the MTJ are triplanar. (Courtesy
Juan C. Garbalosa, University of Hartford, West Hartford, Conn.)

184
Section II  Orthoses in Rehabilitation
Because the axis of the first ray is minimally pitched from
the transverse plane, insignificant transverse motion occurs.4
In contrast, the axis of rotation of the fifth ray is oriented at
a 20-degree angle from the transverse plane and a 35-degree
angle from the sagittal plane. The resulting motions combine
inversion with plantarflexion and eversion with dorsiflexion.
Less motion is present about the axis of rotation of the fifth
ray than of the first ray.4 MTP joints have two separate axes of
rotation: the vertical axis (abduction and adduction) and the
transverse axis (plantarflexion and dorsiflexion).4,13,25 Little
frontal plane motion at MTP joints is normal; frontal plane
motion leads to subluxation.4
Plantar Fascia and Arches of the Foot
The plantar aponeurosis, one of the most functionally impor­
tant soft tissue structures of the foot, is a sheath of fascia
spanning most of the foot's plantar surface. Arising from the
medial process of the calcanean tuberosity, it passes distally
along the plantar aspect of the foot, then divides into five slips
for its distal attachment at the base of the proximal phalanges
by the plantar pads.29 This fascial sheath plays an extremely
important role in providing the stability needed by the foot
during the toe-off phase of stance during gait and in support­
ing the longitudinal arch of the foot.
The medial longitudinal and transverse arches are formed
by the ligamentous and osseous structures of a “normal” foot. 30
The medial longitudinal arch (MLA) extends from the calca­
neus (posterior) to the first metatarsal head (anterior) and is
supported by the plantar aponeurosis, short and long plantar
ligaments, and the spring ligament. During weight bearing,
the height of the arch is reduced as the supporting ligamen­
tous structures are elongated. The transverse arch reaches
across the foot from medial to lateral borders. The height
of the arch varies along the length of the foot: Its maximum
height occurs at the cuboid-cuneiform bones of the midfoot,
and its lowest point is at the metatarsal heads.
FUNCTION OF THE FOOT IN GAIT
The foot and ankle complex has three major functions in the
gait cycle: attenuating the impact forces, maintaining equilib­
rium, and transmitting propulsive forces. For optimal biome­
chanical and energy-efficient performance, the joints of the
foot and ankle must work in harmony. In early stance, the
foot-ankle complex absorbs energy generated at initial con­
tact and decreases forces transmitted to proximal structures
during loading. The foot and ankle must also adapt to surface
conditions encountered by the foot as stance begins. In late
stance, the foot and lower leg transmit propulsive forces gen­
erated by muscles of the lower extremity onto the ground. The
ability of the foot and lower leg to accomplish these functions
depends on the integrity of the various structures of the foot.
Gait abnormalities occur when the foot and ankle complex is
unable to compensate for deficits in motion or structure.
The kinematic, kinetic, and neuromuscular events of
the normal human gait cycle have been described in many
ways.4,31,32 Most focus on five distinct events: initial contact
(IC) or heel strike, loading response (LR) or foot flat, mid­
stance (MSt), terminal stance (TSt) or heel-off, and preswing
(PSw) or toe-off. See Chapter 5 for a more detailed descrip­
tion of the gait cycle.
Shock Absorption
Musculoskeletal structures of the lower limb act from IC to
MSt to attenuate impact forces.4,31,33 Force plate recording of
ground reaction forces (GRFs) estimates the foot's ability to
absorb energy and decelerate the lower leg. The push of the
foot against the floor creates a GRF with three components:
vertical, medial and lateral, and fore and aft forces. The verti­
cal component of a typical GRF record has a bimodal shape
(Figure 8-4). The brief first peak results from the impact of
the heel with the ground. Some of the vertical GRF is attrib­
uted to acceleration of the centers of mass of the foot and
shank of the leg.
In early stance, from IC to LR, the STJ moves into pro­
nation as the TCJ is plantarflexing.4,31,34,35 The fibula and
tibia internally rotate with respect to the foot.22,23 Pronation
of the STJ is controlled by eccentric contraction of the
tibialis anterior, posterior tibialis, flexor hallucis longus,
and flexor digitorum longus muscles.4,31,36 Plantarflex of
the foot is controlled primarily by eccentric action of the
tibialis anterior.4,35 The combined muscle activity deceler­
ates plantarflex and pronation motion of the TCJ, STJ, and
MTJ, slowing vertical and anterior movement of the center
of mass of the foot and shank and decreasing impact forces
encountered at IC.
The viscoelastic plantar fat pad absorbs some of the energy
generated between IC and LR.37 Pronation of the STJ flattens
the arches of the foot, elongating plantar connective tissue
structures. Because these tissues are viscoelastic, they also
absorb some of the energy generated from IC to LR.
100% BW
0
100
FIGURE 8-4  Typical vertical ground reaction pattern during walk­
ing. Note the bimodal shape of the ground reaction force. The first
peak occurs at initial contact, and the second peak occurs during
the toe-off phase of gait. The recorded ground reaction force repre­
sents the whole body center of mass acceleration. BW, Body weight.
(From Valiant GA. Transmission and attenuation of heelstrike accel­
erations. In Cavanagh PR [ed], Biomechanics of Distance Running.
Champaign, Ill: Human Kinetics, 1990. pp. 225-249.)

Chapter 8  Foot Orthoses
185
Adaptation to Surfaces
In everyday walking, the foot must be able to adapt quickly to
many types of terrains and uneven surfaces. The key contrib­
utor to surface adaptation is STJ pronation, which unlocks
the MTJ, permitting the joints of the foot to function in loose-
packed positions and enabling the osseous elements to shift
their relative positions.
At IC, the forefoot is in a supinatory twist (inverted) about
the longitudinal MTJ axis. Eccentric action of the anterior tib­
ialis decelerates plantarflex of the forefoot, lowering it to the
ground. The MTJ becomes fully supinated at LR, as a result
of eversion of the STJ and GRFs acting upward on the foot's
medial border. Contraction of the extensor digitorum longus
and peroneus tertius abducts and dorsiflexes (pronates) the
forefoot, locking it about the oblique MTJ axis and preparing
the forefoot to receive the loading forces encountered at MSt.4
Propulsion
During MSt (LR to PSw), the STJ is maximally pronated and
begins to resupinate. At this time, the GRF maintains the MTJ
in a pronated position about its oblique axis. At the same time,
a pronatory twist is initiated at the longitudinal axis by con­
centric action of the peroneals. The MTJ locks in a fully pro­
nated position around the longitudinal axis just before heel
rise, as the STJ reaches its neutral position. The MTJ must
remain locked in this position throughout propulsion, as
the peroneals contract to lift the lateral side of the foot from
the ground and transfer weight medially to the other foot.
As the heel is raised from the ground, the rearfoot continues
to supinate (talus abducts and dorsiflexes) as the lower limb
rotates externally. This coupled motion necessitates supina­
tion of the MTJ about the oblique axis to maximize joint sta­
bility and convert the foot into a rigid lever for propulsion.
Supination of the STJ occurs with concentric action of the
tibialis posterior, flexor hallucis longus, and flexor digitorum
longus and soleus, as well as the antagonistic functioning of
the peroneus brevis.4,31 The concentric activity of the gastroc­
nemius and soleus muscles causes vertical acceleration of the
foot and lower leg. Propulsive forces generated by the foot
and lower leg are transmitted to the floor.4,31,35 The second
peak of a GRF curve corresponds to propulsion in late stance
phase (see Figure 8-4).
Supination of the STJ and locking of the MTJ about the
longitudinal axis place the foot in a closed-packed position,
transforming the foot into a rigid lever.4,14,23,31 This transfor­
mation is aided by the action of the plantar aponeurosis as
it wraps around the metatarsal heads. During TSt, the MTP
joints extend (dorsiflex), creating a “windlass effect.” This
action compresses joints of the midfoot and forefoot, facili­
tating the transition from flexibility to rigidity required for
effective push-off.
BIOMECHANICAL EXAMINATION
The biomechanical examination of the foot and ankle has three
components: a non–weight-bearing assessment, a static weight-
bearing assessment, and a dynamic gait analysis (Figure 8-5).
Five common intrinsic foot deformities are identified in the
biomechanical examination: rearfoot varus, forefoot varus,
forefoot valgus, equinus deformity, and plantar flexed first ray.
The theoretical model of biomechanical foot and ankle
examination is based on the work of Root and colleagues.4
Debate continues about the validity of Root's criteria for nor­
malcy and the assumption that the STJ is in neutral position
from MSt to TSt of the gait cycle. Reliability of the measure­
ment techniques used to determine STJ neutral position has
also been questioned.38–40 Although controversial, Root's the­
ory and his biomechanical evaluation and treatment tech­
niques are used by many clinicians.
Root describes deviations from normal foot alignment as
“intrinsic” foot deformities, which can lead to aberrant lower
extremity function and musculoskeletal pathological con­
ditions.4,41 To prescribe an appropriate biomechanical foot
orthosis, the source of the pathological condition or defor­
mity must be determined by a detailed patient history and a
comprehensive biomechanical examination.42 This helps the
clinician identify resultant pathomechanical abnormalities
and determine the benefits of orthotic intervention.
NON–WEIGHT-BEARING OPEN CHAIN
EXAMINATION
During the non–weight-bearing open chain examination, the
basic architecture of the foot and ankle is assessed. Any bony
deformities or prominence of the joints, rays (toes), and cal­
losities are noted. The examiner uses a goniometer to locate
the subtalar neutral (STN) position and identify any intrinsic
foot deformities.
The non–weight-bearing goniometric examination is per­
formed with the patient in the prone position, with the targeted
lower extremity positioned with extended knee, and the foot
6 to 8 inches off the treatment table. Placing the contralateral
lower extremity in a figure-four position orients the ipsilateral
lower extremity in the frontal plane, reducing the influence of
proximal rotational limb disorders on measurement.43
Examination of the Rearfoot
Goniometric measurements of the non–weight-bearing exami­
nation assess the rearfoot with respect to STN position, as
well as STJ mobility, based on calcaneal positioning in the
frontal plane. Calcaneal frontal plane motion is the most
readily examined component of triplanar STJ motion. To per­
form the examination, the stationary arm of a goniometer is
aligned with an imagined bisection of the lower third of the
limb (tibiofibular complex), the mobile arm is aligned with an
imaginary bisection of the posterior surface of the calcaneus,
and the axis of the goniometer is aligned at the STJ axis, just
above the superior border of the calcaneus but beneath the
level of the medial and lateral malleoli (Figure 8-6).43,44
Subtalar Neutral Position
STN position can be manually estimated by palpation or
by using a mathematical model developed by Root. If using
palpation, the examiner identifies the anteromedial and

186
Section II  Orthoses in Rehabilitation
FIGURE 8-5  Biomechanical examination form outlining components of the non–weight-bearing
and weight-bearing assessment. Ante, Femoral anteversion; ASIS, anterior superior iliac spine; DLS,
double-limb stance; Gastroc, gastrocnemius; G.T., greater trochanter; ITB, iliotibial band; M.M.,
medial malleolus; PSIS, posterior inferior iliac spine; Retro, femoral retroversion; SLS, single-limb
stance; T.T., tibial tubercle; VAR, varus; VAL, valgus. (Courtesy Stride, Inc., Middlebury, Conn.)
Biomechanical examination form outlining components of the weight-bearing assessment.

Chapter 8  Foot Orthoses
187
anterolateral aspects of the talar head with the thumb and
index fingers of the hand closest to the patient's midline,
placing the thumb just proximal to the navicular tuberosity,
approximately 1 inch below and 1 inch distal to the medial
malleolus (Figure 8-7). In STJ pronation, the anteromedial
talar head is most prominent beneath the thumb, and an
anterolateral sulcus (the sinus tarsi) is apparent. The index
finger is placed in this sulcus, where the talar head is found
to protrude when the foot is fully supinated. The thumb
and index finger of the other hand grasp the fourth and
fifth metatarsal heads, moving the foot in an arc of adduc­
tion and inversion (supination) and abduction and ever­
sion (pronation). STN is the point where the talar head is
equally prominent anteromedially and anterolaterally.41,43,44
FIGURE 8-5—cont'd

188
Section II  Orthoses in Rehabilitation
The examiner then “loads” the foot by applying a dorsally
directed pressure against the fourth and fifth metatarsal
heads until slight resistance is felt. The loading procedure
locks the MTJ against the rearfoot, mimicking GRFs of
MSt.4,45 The angular relation between the bisection of the
calcaneus and the bisection of the lower third of the leg is
measured with a goniometer (see Figure 8-6), recorded on
the evaluation form as rearfoot STN position.
Root's mathematical model for determining STN posi­
tion uses a quantitative goniometric formula.4,41 First, end
ROM calcaneal inversion and eversion are determined by
goniometric measurement. Total calcaneal ROM is the
sum of the inversion and eversion values. The STN posi­
tion is determined as the calcaneus is moved into inver­
sion at one third of the total calcaneal ROM. If end-range
calcaneal inversion is 25 degrees and end-range calcaneal
eversion is +5 degrees, total calcaneal ROM would be 30
degrees. STN position is calculated to be at 5 degrees cal­
caneal inversion, one third of the distance from its fully
everted position.
Reliability and clinical validity of both models have been
debated.40,41,43,46–48 Although acceptable reliability is possible,
it is influenced by examiner experience. Palpation to deter­
mine STN position is efficient in terms of time but requires
more advanced manual skills and experience than the math­
ematical model. The mathematical model may be more reli­
able for the entry-level practitioner.
Calcaneal Range of Motion
Calcaneal inversion and eversion occur primarily at the STJ,
with lesser contributions from the TCJ. Calcaneal ROM
is assessed with the patient in the prone position with the
same anatomical landmarks and lines of bisection as for
STN assessment. The examiner grasps the calcaneus in one
hand, fully inverts it in the frontal plane until end ROM is
achieved, and then takes a goniometric measurement.48 The
procedure is repeated for calcaneal eversion. The TCJ must
be maintained in a neutral to slightly dorsiflexed position
FIGURE 8-7  To determine subtalar neutral position, the examiner
moves the forefoot slowly between supination and pronation until
the anteromedial and anterolateral surfaces of the head of the talus
are equally prominent.
FIGURE 8-6  Non–weight-bearing goniometric technique. A load­
ing force applied by the examiner over the fourth and fifth meta­
tarsal heads locks the forefoot on the rearfoot while the examiner's
opposite hand operates the goniometer to measure subtalar neutral
position and calcaneal range of motion. The examiner is seated at
the distal end of the treatment table, with chair height adjusted to
position the patient's foot at chest level.

Chapter 8  Foot Orthoses
189
while measuring to lock it in a closed-packed position and
better isolate STJ motion.49 Normative values of 20 degrees
for calcaneal inversion and 10 degrees beyond vertical for
eversion have been reported.4
Because values of calcaneal eversion are larger when
assessed in a full weight-bearing position, some clinicians sug­
gest that this position is more clinically valid.38,48 Assessment
of calcaneal eversion in the weight-bearing position repre­
sents a total “functional” pronation and eversion that is the
summation of motion occurring at the STJ and compensa­
tory motion occurring extrinsic to the STJ (e.g., TCJ, MTJ).
Passive assessment of calcaneal eversion in non–weight bear­
ing remains the most accurate method to determine the
degree of composite pronation acquired from the STJ itself.
Talocrural Joint Range of Motion
In normal walking, the TCJ is maximally dorsiflexed just
before heel rise when the knee is fully extended and the STJ is
in a nearly neutral position.4,50 When and whether an actual
STN position ever occurs during gait is disputed.38 The use
of a standard position of knee extension and STN, however,
offers a consistent point of reference when assessing TCJ
dorsiflexion. According to most sources, a minimum of 10
degrees TCJ dorsiflexion is required for normal gait; anything
less is classified as an equinus deformity.4,50–53 A minimum of
20 degrees of plantarflex is also required for normal gait.4
Ankle dorsiflexion is measured in a non–weight-bearing
position with the STJ held in the neutral position and the
knee extended. The examiner forcefully dorsiflexes the ankle
with active assistance from the patient. Active assistance
encourages reciprocal inhibition of the calf muscle group and
is essential for accurate measurement.50 The proximal arm of
the goniometer is positioned along the lateral aspect of the
fibula, the distal arm along the lateral border of the fifth meta­
tarsal, and the axis distal to the lateral malleolus.54 An alterna­
tive placement of the distal arm of the goniometer along the
inferolateral border of the calcaneus may more effectively iso­
late true TCJ dorsiflexion (Figure 8-8). This value is recorded
as rearfoot dorsiflexion. Forefoot dorsiflexion is measured
by repositioning the distal arm along the lateral aspect of the
fifth metatarsal. This method allows the examiner to identify
contributions or restrictions in sagittal plane motion from the
oblique axis of the MTJ.
If ankle dorsiflexion is less than 10 degrees when measured
with the knee extended, remeasurement with the knee flexed
may rule out soft tissue restriction of the gastrocnemius-soleus
complex.4,50 If dorsiflexion values are consistent in both posi­
tions, the limitation is likely a result of osseous equinus forma­
tion of the ankle.
During gait, ankle dorsiflexion occurs in a closed kinetic
chain as the tibia and fibula rotate forward over a fixed
foot. On the basis of this, some have suggested that assess­
ing ankle dorsiflexion may be more accurate with the patient
in a weight-bearing position.38,52 The weight-bearing tech­
nique measures the angle between the tibia and the floor
as the patient leans forward with the foot flat on the floor.
Unwanted compensations are often difficult to control during
weight bearing and may mask true TCJ limitations. The
non–eight-bearing technique allows the examiner to assess
end feel and joint play, as well as mechanical blocks or joint
laxity, providing additional information not accessible in the
weight-bearing examination.
Rearfoot Deformities
Normal rearfoot position is one in which STN is 1 to 4 degrees
of varus.39,40,47,48 Values of more than 4 degrees are described as
a rearfoot varus deformity. This deformity may be the result
of ontogenetic failure of the calcaneus to derotate sufficiently
during early childhood development.4,45,55 Because this defor­
mity is a torsional structural malalignment of the calcaneus,
not a joint-related problem, the TCJ and STJ lines remain
congruent when observed in the non–weight-bearing STN
position. As a structural deformity, it cannot be corrected or
reduced by joint mobilization or a strengthening program.
Instead, it is managed with a functional foot orthosis that par­
tially supports the calcaneus in its inverted alignment while
preventing excessive STJ pronation.
Assessment of calcaneal ROM predicts quality of motion
and the integrity of the STJ. Measuring calcaneal motion into
eversion allows the examiner to determine whether a rearfoot
deformity is compensated or uncompensated (Figure 8-9).
In a compensated rearfoot varus deformity, the calca­
neus fully everts to vertical or beyond in weight bearing
FIGURE 8-8  Alignment of the distal arm of the goniometer along
the inferior-lateral border of the calcaneus may provide a more
accurate measure of talocrural joint dorsiflexion than the traditional
alignment along the shaft of the fifth metatarsal used to measure
overall ankle dorsiflexion.

190
Section II  Orthoses in Rehabilitation
because the STJ possesses an adequate amount of prona­
tory motion to compensate for the deformity. A compen­
sated rearfoot varus deformity of 10 degrees (STN position)
requires that the STJ pronate or evert at least 10 degrees
to enable the medial condyle of the calcaneus to achieve
ground contact in weight bearing. Such excessive pronatory
motion causes medial gapping and lateral constriction at
the STJ line and a medial bulge of the talus as it moves into
adduction and plantarflex.
In an uncompensated rearfoot varus deformity, the cal­
caneus remains fixed in its inverted STN position with no
eversion motion at the STJ. A partially compensated rear­
foot varus deformity allows for partial STJ eversion so
that the medial condyle of the calcaneus does not make
complete contact with the ground on weight bearing.
Alternative compensatory motion, extrinsic to the STJ, is
necessary to achieve weight bearing on the medial aspect
of the foot. One common compensation is an acquired soft
tissue (valgus) deformity of the forefoot caused by a plan­
tar flexed first ray. Other sources of compensatory motion
can occur at the MTJ or proximally at the knee, hip, or sac­
roiliac joints.
An equinus deformity occurs when fewer than 10 degrees
of ankle dorsiflexion are available as a result of osseous or
muscular problems.51,53,56,57 Clubfoot (talipes equinovarus)
is a congenital osseous deformity that includes varus defor­
mity of both rearfoot and forefoot, rearfoot equinus, and
an inverted and adducted forefoot.58,59 The angular rela­
tion between the body and the head and neck of the talus is
decreased, and the navicular is shifted medially. Muscular
forms of equinus include congenital or acquired soft tissue
shortening or muscle spasm.53 Tissue contracture or short­
ening occurs in both contractile tissues (gastrocnemius,
soleus, and plantaris) and noncontractile tissues (teno-
Achilles and plantar fascia).51,53
Compensation for an equinus deformity occurs at the
foot through pronation, perpetuating soft tissue contrac­
tures. The STJ is forced to pronate maximally to gain as much
sagittal plane dorsiflexion as possible. Although foot pro­
nation allows some dorsiflexion from the STJ, the amount
is often inadequate. Pronation of the STJ unlocks the MTJ,
creating an unstable midfoot while allowing further dorsi­
flexion and forefoot abduction from the oblique axis of the
MTJ.53 Other compensatory strategies for equinus deformity
include knee flexion (especially in individuals with cerebral
palsy), early heel rise, toe walking, shortened stride length
of the contralateral lower limb, and toe-out walking.31,41,53
Clinical consequences of long-term ankle equinus include
many conditions normally associated with the excessively
pronated foot: plantar fasciitis, heel spurs, bunions, and
capsulitis.53
Examination of the Forefoot
Forefoot position is assessed with the STJ in neutral posi­
tion. Because the first and fifth rays have independent axes
of motion, forefoot orientation is defined by the planar rela­
tion of the second, third, and fourth rays to the bisection line
of the calcaneus.
A
1
Medial calcaneal
condyle unloaded
B
Calcaneus
inverted
2
4
5
3
1
STJ
gaps
medially
Calcaneus
inverted
2
3
4
5
FIGURE  8-9  A, In relaxed calcaneal stance, compensation for a
rearfoot varus is normally subtalar joint pronation. B, In an uncom­
pensated rearfoot varus, the subtalar joint cannot pronate and instead
may develop compensatory midtarsal joint pronation about the
longitudinal joint axis. (Courtesy Stride, Inc., Middlebury, Conn.)