Plastic Surgery Volume 6: Hand and Upper Extremity (4th Edition) – Peter C. Neligan

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SECTION IV
CHAPTER 25 • Congenital hand I: Embryology, classification, and principles
likely to confront in the future; and the possible methods
and timing of procedures aimed at improving function and
appearance. Photographs and models of pre- and postopera­
tive example cases are beneficial in demonstrating expected
outcomes. They also provide reassurance that surgery is not
disfiguring.
History
Following introductions, a preliminary examination through
observation alerts the surgeon to possible diagnoses and
associations. A detailed history of the pregnancy, its duration
and any untoward events, the lie of the child in utero, and the
method of delivery and birth weight provide valuable infor­
mation. The presence of a positive family history of limb
anomalies in siblings, parents, and the relatives of parents is
suggestive of an inherited disorder. The surgeon should
always question as to whether there are anomalies in other
systems and whether a general pediatric review has been
performed. The need for further specific system review may
become apparent during the assessment.
Examination
Observation of the child at play provides much information,
which may be withheld if the surgeon approaches a direct
physical examination of the child either too early in the assess­
ment process or too brusquely.
An understanding of developmental milestones is integral
to recognition of delayed or abnormal functional develop­
ment (Table 25.3).108 The child’s upper limb movements are
mainly reflexive at birth. There is a rudimentary grip via digit
flexion. The thumb is clasped within the palm but exhibits
reflex extension when startled.109,110
The development of prehension is well summarized by the
work of Erhardt and Lindley.111 These patterns are depicted in
Fig. 25.23. They demonstrate the development from rudimen­
tary grasp utilizing an ulnar power grip, to precision function
radially incorporating the thumb. Fig. 25.24 demonstrates the
Assessment of the child and family
There are great rewards in treating children who are unfortu­
nate enough to be born with hands we recognize as less than
perfectly formed. Adaptive ability in the child is quite extraor­
dinary, such that some question the wisdom of surgical
interference for many presentations. Furthermore, initially,
the hand is normal to the child. It is a growing awareness of
the “normal” environment that alters the child’s perception.
However, it is the observation of many that the child reflects
the attitudes of others. If parents, relatives, friends, doctors,
or therapists consider the problem to be overwhelming, the
child will be more likely to have a problem.
For the surgeon, the opportunity to observe the develop­
ment of the child and hand function during growth and
learning provides a satisfaction that cannot be underestimated.
Decision-making must be precise and involve parents and
child such that all develop a confidence that the treatment is
both appropriate and in capable hands. Few surgical fields
allow greater application of surgical principles to the manage­
ment of deformity and loss of function. The aim is to achieve
optimal hand function – prehensile grasp and dexterity of
fingers and thumb for fine activity – whilst also striving for
optimal appearance.
The involvement of family doctor and pediatrician, thera­
pist, and psychologist in the overall management of child and
family is necessary. The geneticist can assist in identifying
inheritance factors and advise regarding risk of recurrence for
subsequent children. Specialist medical care is often required,
as involvement of systems other than the musculoskeletal
system is common. Specifically, cardiac, hematological, neu­
rological, gastroenterological, and urological systems must
be investigated for abnormalities. Many syndromic patterns
have been described and alert the surgeon and treating physi­
cians to probable associations. Finally, support groups can be
of significant benefit. Often parents and children find great
solace and encouragement from discussing their problems
with others with similar afflictions.
The clinic
A calm, private, and warm environment is conducive to
optimal assessment. Parents, often young, may be over­
whelmed by the medical and paramedical attention that has
been directed towards them and their child. At the initial
introduction, the child and parents should not be confronted
by too many foreign faces, perhaps only the surgeon and one
other. Minimally, the surgical congenital hand clinic should
also have immediate access to experienced occupational
therapists and physiotherapists. In developed societies, an
assessment of all other systems has been completed or is in
progress before consultation with the hand surgeon. However,
it is vital that the treating surgeon has sufficient understand­
ing of the processes of normal and abnormal limb develop­
ment and is sensitive to the association of other system
anomalies with specific hand and upper limb anomalies. The
parents expect and should receive information from the
surgeon regarding: the cause and mechanism of dysmorpho­
genesis; the likelihood of recurrence in subsequent children,
and the likelihood of recurrence in future children of the
presenting child; a description of the dysfunction the child is
Table 25.3  Development of hand control
Hand control
When achieved
(months)
Grasp small objects by ulnar–palm prehension
4
Grasp by partial thumb opposition
5
Transfer objects between hands
6
Grasp by full thumb opposition
7
Bang an object on a flat surface
7
Drink from cup held in hand with assistance
9–10
Pincer grasp
12
Scribble with crayon
13–15
Throw ball
18
Build a tower with 4–6 blocks
24
(Reproduced from: Gupta A, Kay SPJ, Scheker LR (eds). The Growing Hand:
Diagnosis and Management of the Upper Extremity in Children. London: CV
Mosby; 2000:51.)

567
Assessment of the child and family
Fig. 25.23  (A–D) The development from rudimentary grasp, utilizing an ulnar power grip to precision function radially incorporating the thumb. (Redrawn after Erhardt RP.
Developmental Hand Dysfunction: Theory, Assessment, and Treatment, 2nd edn. San Antonio: Therapy Skill Builders; 1994.)
5 months
7 months
9 months
7 months
8 months
9 months
10 months
5 months
7 months
9 months
1–1.5 years
Palmar-supinate
2–3 years
Digital-supinate
3.5–4 years
Static tripod
4.5–6 years
Dynamic tripod
A
B
C
D
Fig. 25.24  Change in weight-bearing through the upper
limbs through the first 5 months of life. (Redrawn after
Erhardt RP. Developmental Hand Dysfunction: Theory,
Assessment, and Treatment, 2nd edn. San Antonio:
Therapy Skill Builders; 1994.)
1 month
2 months
3 months
4 months
5 months

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SECTION IV
CHAPTER 25 • Congenital hand I: Embryology, classification, and principles
reveal the complete picture. For instance, the Wassel classifica­
tion of thumb duplication relies on relative skeletal maturity
to distinguish a type 1 from a type 2. The bony connection
present in the former may not be apparent at the base of the
terminal phalanges in initial X-rays until ossification of a
cartilaginous connection has occurred. In most instances,
X-rays should be repeated immediately prior to surgical
intervention as the skeletal appearance may have changed. It
is helpful to have available in the clinic sample hand X-rays
and charts that detail the timing of appearance of ossification
centers and closure of growth plates (Fig. 25.25).115,116 The
method of Greulich and Pyle117 and that of Tanner et al.118 are
the most commonly used for measurement of skeletal matura­
tion. In the former, the patient’s radiograph is matched with
an atlas image of the appropriate age.117 One must be careful
to differentiate actual age and maturity. The Tanner and
Whitehouse method is more complex and is based on the rate
of development of 19 individual bones.118 Both methods suffer
from the problem of variation between races. Progress is
delayed in European children in comparison with those from
Africa and North America.119 Poor nutrition results in slower
maturation. Maturation in girls is more rapid than in boys by
2 years.
Fluoroscopy, tomography, and arthrography may all have
a limited place in the assessment of the pediatric hand, often
more for injury than for congenital anomaly. Computed
tomography and magnetic resonance imaging have replaced
many of these modalities but do require sedation or general
anesthesia for the child. Ultrasonography has many charac­
teristics that make it an ideal imaging modality in that there
is no ionizing radiation, and it is painless and inexpensive.
However, it is operator-dependent and differentiation between
change in weight-bearing through the upper limbs over the
first 5 months of life.
Determination of hand dominance is usually not
possible in the first year or so but becomes apparent by
age 5.112–114
A general examination includes observation of the facial
appearance with specific attention to eyes, ears, mouth, and
jaw, examination of the spine and lower limbs, observation
and palpation of the chest wall and abdomen where appropri­
ate, and examination of all four limbs.
It often allays the child’s distrust for the surgeon to take
the mother’s hand, gently examine this and return it to its
owner, before attempting the same with the child. The expe­
rienced examiner will note any deformity and size discrep­
ancy, diminished passive and active ranges of motion in any
particular joint, often in association with poorly developed or
absent skin creases, and joint instability. Some changes are
subtle. A close examination of a child with second-web syn­
dactyly in the feet may reveal subtle webbing of the third
webs in the hands. This may also be present in the hands of
the parent(s). Obvious thumb hypoplasia in one hand may be
accompanied by subtle changes in the other.
All findings must be precisely recorded. Tracings, measure­
ments of girth, and clinical photographs provide objective
data for comparison at subsequent assessments.
Investigations
The mainstay of investigation is radiological. Plain X-rays
should be requested for the specific anomaly with which the
child presents but should be extended to a broader skeletal
survey as indicated. Of course, the immature skeleton will not
Fig. 25.25  Timing of appearance of ossification centers and closure of growth plates. (Reproduced from Upton J. Classification of upper limb congenital differences and
general principles management. In: Mathes SJ (ed.) Plastic Surgery, 2nd edn, vol. 8. Philadelphia: Elsevier; 2006:27.)
Primary appearance
2.0 to 4.0 fetal months
2.0 to 6.0 fetal months
2.0 to 4.0 fetal months
2.0 to 4.0 fetal months
Ossification centres
Secondary
appearance
Secondary fusion
Boys/Girls (mean)
5.0 mo. to 2.0 yr.
13.1
11.2
5.0 mo. to 2.0 yr.
16.0
12.7
5.0 mo. to 2.0 yr.
14.5
12.9
10.0 mo. to 2.0 yr.
14.4
13.1
Trapezium
1.5 to 10.0 yr.
9.1
9.0
Trapezoid
2.5 to 5.0 yr.
9.1
9.0
Capitate
Birth to 6.0 mo.
15.0
13.1
Hamate
Birth to 6.0 mo.
15.0
13.1
Triquetrum
6.0 mo. to 4.0 yr.
12.7
11.1
Lunate
6.0 mo. to 9.5 yr.
15.3
10.3
Scaphoid
2.5 to 9.0 yr.
9.4
8.8
4.0 to 9.0 yr.
10.3
9.9
3.0 mo. to 1.5 yr.
16.3
15.8
13.0 mo. to 4.0 yr.
12.6
12.0
12.9
12.0
13.6
12.0
Pisiform
6.5 to 16.5 yr.

569
Principles of surgical management
is incomplete or inadequate is not in itself an indication for
surgical reconstruction.
Function
A stable shoulder, arm, elbow, and forearm enable appro­
priate positioning of the hand in space for function. The
instability, deformity, and shortening of radial longitudinal
deficiencies, for instance, severely compromise hand function.
Hand function itself depends on the ability to use a mobile
thumb ray against other parts of the hand, ulnar digits for
grasp and radial digits for precision pinch. Adequate digit
length, stability, and motion are necessary components of
optimal hand use. Surgical decisions may be best guided by
a simple assessment, asking whether the size and number of
digits are appropriate, whether deformity requires correction,
whether stability is a problem, and whether an improvement
in mobility would benefit.
Some decisions regarding surgery are relatively easy. Most
parents and children will request that an extra digit be
removed, particularly if it gets in the way (Fig. 25.26). Occa­
sionally social and/or religious mores will dictate otherwise.
Removal of a type 3 hypoplastic thumb, with subsequent
pollicization of the index finger, may prove to be less palatable
for parents, as they fear a decision that results in four rather
than five digits. As a principle, when confronted with the
option of reconstruction or removal of a part, it is perhaps
wiser to advise reconstruction if the part is incorporated into
the child’s activities, even if in an inefficient manner. The child
and surgeon may benefit from the opinions of others who are
experienced in this field of surgery. Advice from a knowledge­
able colleague is particularly reassuring.
It is often not possible to restore normal function, even for
what would appear to be a straightforward reconstruction of
a Wassel type 1 thumb duplication, in which some joint
instability and some compromise in interphalangeal joint
motion may remain postoperatively. For complex duplica­
tions, full function and normal size are difficult to achieve,
tissues can be problematic. It is helpful in assessing cartilagi­
nous contours prior to ossification.
Vascular studies, such as angiography, magnetic resonance
angiography (MRA), or Doppler flow studies, may be consid­
ered prior to procedures involving vascularized tissue transfer,
including toe transfers, particularly to parts with anomalous
anatomical development. In particular, angiography and
MRA, although uncommonly performed, may be indicated in
some specific vascular reconstructions and for assessment of
vascular tumors.
It is beyond the scope of this chapter to detail a complete
investigation of all systems of the child with congenital limb
anomalies. The incidence of associated anomalies is high. For
instance, thrombocytopenic absent radius, Fanconi anemia,
Holt–Oram syndrome and the VACTERLS association may
accompany a longitudinal radial deficiency. A cardiac echo­
gram, renal ultrasound, and blood examinations are routine.
Diagnosis
Following the assessment and investigations, a classifiable
diagnosis is usually evident. The surgeon, with assistance
from medical colleagues, will have determined whether the
anomaly is isolated or syndromic; whether a genetic abnor­
mality is present through either a spontaneous mutation or
an inheritance pattern; and whether there has been an abnor­
mal formation of tissue, a breakdown of normal tissue, or a
lack of organization of cells into normal tissue.
Principles of surgical management
Indications
When considering surgery, the following question must
always be asked: “Is reconstructive surgery likely to improve
function and/or appearance with minimum risk?” That a part
Fig. 25.26  The obvious deformity of
thumb triplication.
A
B

570
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CHAPTER 25 • Congenital hand I: Embryology, classification, and principles
as many psychological factors are involved, including that of
guilt in having given birth to a “less than normal” child and
the responsibility of having made a decision to subject that
child to surgical intervention.
It is the responsibility of the surgeon to provide advice
based on training, experience, and a knowledge of the litera­
ture. However, should that advice be rejected, the doctor–
patient/parent relationship must not become adversarial.
Repeated assessments over a period of time will usually lead
to an agreeable solution.
Timing
The question of timing is vexatious. Surgical results may be
compromised by the technical difficulties of procedures on
small structures in early life. This must be balanced against
the principle of providing the child with a final result as early
as possible, such that learned patterns of use do not compro­
mise optimal function following appropriate surgical recon­
structions. It is a reasonable approach to allow the child to
adapt to the new hand as early as possible. However, cortical
plasticity allows significant adaptation at older ages and, if
the surgeon is doubtful that the surgery is indicated or the
parents demand delay, it is preferable to wait. If functional
improvement is unlikely and if the indication for surgery is
one of a questionable improvement in appearance, perhaps
the child should make this decision for him- or herself at an
older age.
Parents may wish to defer surgery in the hope that there is
something new on the horizon that will, if not cure, at least
improve the outcome. It is the surgeon’s responsibility to
encourage hope but to discourage unrealistic expectations.
Having failed to make a decision at the optimal time, these
decisions rarely become easier with further passage of time.
Web pages are full of information, some beneficial, some not.
Some is simply advertising.
Table 25.4 details common practice as it relates to timing of
specific surgical procedures, although it is recognized that
more urgent treatment of life-threatening conditions will
delay hand surgery.120 It will be seen that many anomalies are
treated within the first 2 years of life. In principle, the devel­
opment of progressive deformity is an indication to operate
earlier. An example is a syndactyly of the fourth web with
terminal phalanx fusion (Fig. 25.28). Release of the first web,
such as in an Apert hand, should be early. It is beneficial to
complete most surgical procedures prior to school age, par­
ticularly in those instances in which appearance is significantly
improved, such that teasing and ridicule by other schoolchil­
dren are minimized. However, some procedures, such as
minor revision surgery for the Apert hand or limb lengthen­
ing for the short forearm of a radial longitudinal deficiency,
may be indicated at an older age (Fig. 25.29).
Finally, expectations of all involved must be realistic.
Despite the rewards for surgeon, child, and family following
surgery for congenital limb anomalies, an apparently suc­
cessful and pleasing surgical result may be compromised
by recurrent deformity, inadequate growth, uncontrolled
growth, or the development of instability or immobility. At
the time of operation the surgeon needs to be aware of the
presence of factors that may, with time, subsequently alter the
early result. In principle, these require correction at the initial
surgery.
and pollicization never creates a normal thumb. Trigger
thumb release should result in normal use and appearance.
Clinodactyly of the little finger may represent no functional
deficit preoperatively. Surgical interference should be care­
fully considered. Surgery for camptodactyly may improve
extension at the expense of full flexion.
Appearance
The stigmata associated with an abnormal appearance are
obvious. The hands are expressive and communicative.
Deformity of a part is often more obvious than its absence and
its correction may clearly result in an improved appearance
for all eyes (Fig. 25.27). However, for many severe deformities
it is simply not possible to create a normal-looking hand.
Surgery to improve appearance in these cases must be under­
taken realistically. Whether the appearance is improved,
remains the same, or is poorer following surgery is simply in
the eye of the beholder. Toe transfer for symbrachydactyly is
one procedure that excites argument, with some adamant that
appearance is improved and some adamant that it is not and
that appearance should not play a role in decision-making.
Probably the argument is irrelevant. The hand remains differ­
ent regardless of the surgical reconstruction and the surgeon
should not impose his or her views regarding appearance.
Postoperative questionnaires in which patients and parents
state their belief in an improved appearance are often flawed,
A
Fig. 25.27  (A,B) Pleasing appearance and function following pollicization.
B

571
Congenital trigger thumb
assessed by a questionnaire at 12 months of age, only two had
developed trigger thumbs within that period, an incidence of
3.3 per 1000 live births. Three other children subsequently
developed trigger thumbs, one bilateral, after the age of 12
months. Although response to the 12-month questionnaire
was only obtained from 53% of patients and the true preva­
lence of trigger thumb after 12 months in this cohort of
patients cannot be established, this study does tend to suggest
that trigger thumb deformity is an acquired condition and is
not present at birth. However, if the incidence of one patient
per 2000 live births, as described by Ger et al., is accurate, the
number of children required to establish an absence of trigger
thumb at birth would need to be far greater than those exam­
ined in the study.130
Trauma has been incriminated as a possible cause of
acquired trigger thumb. However, the absence of this history
is more usual than not. Furthermore, the definition of what is
a traumatic incident and what is not in a 2-year-old is unclear.
Notta described a node affecting the flexor tendons of
digits that impeded their movement.131 Notta’s node is pal­
pable proximal to the A1 pulley in children with a locked
flexion deformity. If the deformity is correctable, either
actively or by the examiner’s passive extension of the digit,
the node can be felt to click as it passes beneath the A1 pulley.
Some consider the node to be primary, preventing passage of
the tendon past the edge of the obstructing A1 pulley. Most
believe that this is a secondary phenomenon consequent upon
Congenital trigger thumb
Although congenital trigger thumb does not fit well into any
classification scheme for congenital hand anomalies, it is one
of the most common pediatric hand problems in practice.
Etiology
Pediatric trigger thumb is a stenosing tenovaginitis of the
flexor pollicis longus tendon within its fibro-osseous tunnel,
with the obstruction to tendon glide occurring at the A1
pulley. Controversy continues as to whether this is a true
congenital condition or whether it is an acquired condition.
The distinction between the two would appear to rely on
whether or not the condition is present at birth. Although
many authors have described presence at birth, the majority
of these studies depend upon a retrospective history from the
parents. The presence of trigger thumb in twins, the frequent
bilateral nature of trigger thumb, and the association of trigger
thumb with trisomy 13 are factors that have been used to
support the theory of a congenital cause.121–125 However,
several investigators have performed assessments within the
early postnatal period, finding an absence of trigger thumbs
in a combined number of 9000 neonates.126–128 The study of
Kikuchi and Ogino examined 1116 babies within 14 days of
birth.129 None presented with trigger thumbs. Of 601 children
Table 25.4  Common practice relating to timing of specific surgical procedures
Condition
Procedure
Timing
Syndactyly
  Simple
Release
12 months
  Unequal digits with bony tether
Release
6 months
  Including thumb
Release
6 months
  Apert’s acrosyndactyly
Sequential simultaneous bilateral releases
Begin at 6 months
Constriction ring syndrome
  Digit at risk
Release
Immediate
  Acrosyndactyly
Release
6 months
Floating digit(s)
Excision
3 months
Thumb duplication
Reconstruction
12 months
Postaxial or central polydactyly
Reconstruction
12 months
Absent or inadequate thumb
Pollicization
12–18 months
Thumb hypoplasia
Reconstruction
12–18 months
Central longitudinal deficiency
Reconstruction
12–18 months
Symbrachydactyly
Toe phalangeal transfer
12–24 months
Vascularized toe transfer
2–3 years
Radial longitudinal deficiency
Distraction
3–6 months
Stabilization
6–12 months
Clinodactyly
Physeolysis
4–6 years
Osteotomy
Late
Camptodactyly
  Fixed with joint changes
Joint and soft-tissue release
12–18 months
  Soft tissue
Release and transfers
After 2 years
Trigger thumb
Release
After 12 months
(Reproduced from Tonkin MA. An introduction to congenital hand anomalies. Handchirurgie. 2004;36:75–84.)

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SECTION IV
CHAPTER 25 • Congenital hand I: Embryology, classification, and principles
resolution in 53 thumbs diagnosed before the age of 6 months,
following 40 months of nonoperative therapy.130 Steenwerckx
et al. reported similar findings in 57 thumbs after 6 months.132
Other reports document high rates of spontaneous resolu­
tion,132–138 up to 96% for those thumbs that trigger during
active extension, with a lesser resolution rate for those with a
fixed flexion posture.133 Dinham and Meggitt observed a
spontaneous recovery rate of 30% in those children presenting
with trigger thumb prior to the age of 6 months and a rate
of 12% for those presenting between 6 and 30 months.124
They advised treatment guidelines accordingly, advising that
trigger deformities present in the early postnatal period
should be observed for 12 months; those presenting between
the ages of 6 and 30 months should be observed for 6 months;
and that operative treatment should be performed before the
age of 4 years to prevent the creation of residual flexion
deformities. Although there has been an occasional report of
interphalangeal (IP) joint radial deviation and a rotational
deformity of the IP joint in older children,139 there are no
reported instances of persistent deformity if the condition is
corrected surgically by the age of 3 years, or even later, accord­
ing to some authors.140
Fig. 25.28  Deformity of ring finger secondary to a four–five syndactyly.
A
Fig. 25.29  (A,B) Correction of deformity and length for radial longitudinal
deficiency at age 8.
B
the bunching of the tendon as its passage is impeded. It seems
to disappear following surgical release, which supports the
latter theory.
Two other observations are interesting. The first is that
there is a percentage of “trigger thumbs” that present with the
digit locked in extension. In this instance, the failure to glide
through the A1 pulley is from distal to proximal when Notta’s
node presumably abuts against the distal end of the A1 pulley.
The literature does not provide us with an incidence of trig­
gering in extension; indeed some may have interpreted this
as a spontaneous resolution of triggering in a digit previously
locked in flexion.
The second observation is that many children with a trigger
thumb have hyperextensibility of the metacarpophalangeal
joint. Ligamentous laxity is greater in children. No study has
made a comparison of the incidence and degree of metacar­
pophalangeal joint hyperextension in children with and
without trigger thumbs. However, it is logical to propose that
the diameter of the A1 pulley, which is attached to the palmar
plate of the metacarpophalangeal joint, decreases during
hyperextension of the metacarpophalangeal joint, potentially
restricting gliding of the tendon.
The current evidence suggests that the appearance of
trigger thumb is more likely to be after birth. There is no real
evidence of a primary pathological process other than a mis­
match in size between the flexor tendon and the pulley.
Management
The rate of spontaneous resolution following observation and
the rate of resolution following a combination of observation,
manipulation and splinting, vary. Ger et al. found no cases of

573
Congenital trigger thumb
incision is transverse at the base of the thumb (metacarpopha­
langeal joint level). This incision is not easily extensile and
therefore its position is important if one is to obtain an optimal
view of the A1 pulley. If Notta’s node is easily palpable, an
incision centered on this node provides very adequate access.
Often, this leads the surgeon to an incision halfway between
the two basal thumb creases that are present in most hands.
The neurovascular bundles of the thumb lie more anteriorly
than those of the digits. The A1 pulley should be visualized
and palpated with the tip of forceps to identify its proximal
and distal edges. The surgeon or assistant should not attempt
to passively correct the flexion deformity manually prior to
incision of the A1 pulley. Full and easy correction following
pulley release provides evidence of a complete release. The
incision should be made in the midline of the pulley or erring
to its radial side. This avoids continuing the incision through
the fibers of the oblique pulley, whose origin on the ulnar side
abuts the distal end of the A1 pulley. Occasionally, there are
further transverse fibers just distal to, but separate from, the
A1 pulley, which deserve release.
With careful attention to detail, complications should be
minimal to nil. Absorbable 6/0 Vicryl Rapide sutures avoid
the necessity for suture removal. Bathing and massage can
begin at about 7–10 days postoperatively. Although Michifuri
et al.142 reported a complication rate of 15%, including digital
nerve injury, this is not the author’s (MT) experience. There
may be some inflammatory response during wound healing
but this settles once the sutures have dissolved or are rubbed
out with massage.
Recently Baek et al. found a 63% rate of spontaneous reso­
lution in 71 trigger thumbs.141 No treatment was instituted in
these children who were assessed 6-monthly for a minimum
period of 2 years. They found that the flexion deformity can
be expected to improve even in those patients who did not
have complete resolution. The general trend in the literature
pertaining to children of Asian descent is to recommend a
prolonged period of observation with or without splinting
and passive exercises.
From the above it can be seen that the necessity for and
timing of surgery for pediatric trigger thumbs are open to
debate. Most would advise surgery for persistent painful
episodes of triggering. Intermittent, non-painful triggering
may be safely observed for a prolonged period of time, with
or without the addition of night splinting in extension, without
fear of the complication of joint deformity. It is questionable
as to whether or not treatment with night splints for an
extended period of time (up to 5 years or longer) is a greater
imposition on child and parents than a surgical procedure. It
is the author’s (MT) practice to offer the parents surgical
release if there is a persistent flexion or extension contracture
for longer than 3 months and/or if there is accurate documen­
tation by the parents of an uncorrectable flexion contracture
for 12 months. However, this advice is offered along with the
information that spontaneous resolution may well occur, even
in these circumstances.
Surgical procedure (Video 25.1 )
The surgical procedure is performed as day-only surgery
under general anesthesia and with an arm tourniquet. The
1. Swanson AB. A classification for congenital limb malformations. J
Hand Surg. 1976;1:8–22. This is a widely cited classification scheme for
congenital anomalies of the limb. The rationale for its design and use is
presented.
3. Ezaki M, Baek GH, Horii E, Hovius S. IFSSH Scientific Committee
on Congenital Conditions. J Hand Surg Eur Vol. 2014;39:676–678.
10. Burke AC, Nelson CE, Morgan BA, et al. Hox genes and the
evolution of vertebrate axial morphology. Development.
1995;121:333–346. Hox genes are known to play a role in anterior–
posterior segmental identity. This study describes in situ hybridization
and immunolocalization data in chick and mouse embryos demonstrating
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trigger thumb of childhood. Turk J Pediatr. 2003;45:237–239.
140. Skov O, Bach A, Hammer A. Trigger thumbs in children: a
follow-up study of 37 children below 15 years of age. J Hand Surg
[Br]. 1990;15:466–467.
141. Baek GH, Kim JH, Chung MS, et al. The natural history of
pediatric trigger thumb. J Bone Joint Surg Am. 2008;90:980–985.

573.e4
SECTION IV
CHAPTER 25 • Congenital hand I: Embryology, classification, and principles
142. Michifuri Y, Murakami T, Kumagai S, et al. Natural history of the
trigger fingers in children [in Japanese]. Seikeigeka (Orthop Surg).
1978;29:1648–1650.
143. Dimitrov BI, Voet T, De SL, et al. Genomic rearrangements of the
GREM1-FMN1 locus cause oligosyndactyly, radio-ulnar synostosis,
hearing loss, renal defects syndrome and Cenani–Lenz-like
non-syndromic oligosyndactyly. J Med Genet. 2010;47:569–574.
144. Zhou F, Leder P, Zuniga A, et al. Formin1 disruption confers
oligodactylism and alters Bmp signaling. Hum Mol Genet.
2009;18:2472–2482.

SECTION IV • Congenital Disorders
26 
Congenital hand II: Longitudinal, central,
and transverse deficiency
Scott Oishi and Lesley Butler
SYNOPSIS
■ Clinical evaluation of the entire patient is essential as multiple
associated findings may exist.
■ It is important to remember that untreated patients function very well,
so any surgery, needs to be assessed on an individual case basis and
should only be performed if there is a realistic goal of increasing
function.
■ If a syndactyly exists but the finger tips are separated and no
significant tethering exists, reconstruction should be delayed until the
child is in the 2–3 year-old age range as to minimize possible effects
of anesthesia as well as to allow the fingers to be bigger and easier to
perform surgery on.
Introduction
Upper limb development occurs very early during fetal devel­
opment, with ingrowth into the ectoderm by the mesoderm
signaling the initiation of limb bud development.1–3 This
begins about 28 days after fertilization and is completed by
about day 56. The development is regulated by a complex
feedback mechanism that determines growth, orientation,
and differentiation of the three axes: longitudinal, radio­
ulnar, and ventral–dorsal. Critical areas include the apical
ectodermal ridge (AER), zone of polarizing activity (ZPA),
and the dorsal ectoderm, which are regulated by fibroblast
growth factors (FGF), sonic hedgehog, and the Wingless-type
(Wnt) pathway respectively3 (Fig. 26.1). It should be noted,
however, that these pathways do not act solely independently
and instead rely on feedback mechanisms from each other for
growth and differentiation of the upper limb. Abnormalities
occurring during this crucial time period of development can
lead to abnormalities of longitudinal, central, and transverse
deficiencies. In a series of eloquent experiments, Ogino and
his group were able to induce ulnar and radial longitudinal
deficiencies in rats by administering busulfan at different
points in early development of the upper limb (weeks 4 and
5 of fetal development). Greater doses of busulfan led to
both a higher incidence and severity of ulnar or radial lon­
gitudinal deficiency.4–5 Transverse deficiencies have not been
reproduced in animal models; however, it is speculated that
subclavian artery disruption at an early developmental stage
may lead to the clinical findings associated with transverse
deficiencies.6
Patients with longitudinal, central, and transverse defi­
ciency can face significant societal issues as they grow and it
is important for them to have support groups, child-life spe­
cialists, and child psychologists available, not only to them,
but also to their parents. Counseling for the parents is also
important at the first visit regarding potential etiologies of the
underlying conditions as many of them have significant feel­
ings of guilt and confusion. At Texas Scottish Rite Hospital for
Children, we started a hand camp many years ago, which has
been an integral part of treatment of these patients, as it allows
them to interact and talk with other children with either the
same or different congenital hand difference diagnosis.
Radial longitudinal deficiency
Basic science/disease process
Radial longitudinal deficiency (RLD) is the most common
upper limb longitudinal deficiency, with an incidence that
has been reported as between 1 : 5000–100 000 live births,7–9
being bilateral in 38% to 58%.9 It can range from involvement
of the entire upper limb to thumb involvement alone. In
1976, the International Federation of the Societies for Surgery
of the Hand (IFSSH) adopted the classification system of
congenital hand differences proposed by Swanson.10 In this
classification, RLD is considered in the IB group (failure
of formation – longitudinal arrest). Since its publication,
many conditions have been found to not fit into this system.
An expanded classification system, OMT (Oberg–Manske–
Tonkin), has recently been introduced to more accurately
categorize congenital hand differences.11 (see Table 25.2 for

575
Radial longitudinal deficiency
agenesis, and limb anomalies) represents an association and is
not an inherited disorder. A minimum of three of these clinical
findings need to be present before the VACTERL diagnosis is
made. Thalidomide was a medication which previously was
given to pregnant women to treat nausea and morning sick­
ness, but was unfortunately found to have a high incidence
of RLD and other skeletal deficiencies in the newborn when
given between days 38 and 45 of fetal growth.13 In addition,
maternal use of valproic acid, phenobarbital, and aminopterin,
as well as fetal alcohol syndrome, have also been associated
with RLD.14–16
Diagnosis/patient presentation
Bayne and Klug (1987) initially classified radial deficiency
into four types17; however, this was later expanded by James
et al.18 to include types 0/N and also by Goldfarb et al. (2005)
to include a more proximal variant (phocomelic), type V19
(Table 26.1). A type 0 radius is of normal length (< 2 mm
short), with the 0/N modifier reflecting whether the carpus is
normal (N) or abnormal (0); a type I radius is at least 2 mm
short (measured between distal physis of radius and ulna); a
type II radius is termed a “miniature radius” with proximal
and distal physes present; a type III radius only has remnant
of radius with absent distal physis; and type IV is an absent
2015 version). In this system, RLD with thumb hypoplasia
and forearm involvement would be I.A.2.i, and thumb
hypoplasia without forearm involvement would be I.B.2.i.
Although many cases occur as a sporadic mutation, some
are related to an inherited condition. For example, Holt–
Oram syndrome is an autosomal-dominant condition that
has been mapped to a mutation on chromosome 12 at the
location of the TBX-5 gene.12 In affected individuals, this
presents as RLD along with cardiac abnormalities. Although
the most common cardiac abnormality present is a septal
defect, conduction abnormalities can also be the lone cardiac
finding. Obviously this can be an important consideration
for the patient undergoing surgery, and must be conveyed to
the anesthesiologist. TAR (thrombocytopenia absent radius)
syndrome is inherited in an autosomal-recessive fashion and
can present with profound thrombocytopenia as a newborn.
However, this usually improves/resolves over the first year
of life and overall prognosis is good. These patients usually
have bilateral involvement with thumbs that are present,
albeit hypoplastic. Another autosomal-recessive condition is
Fanconi’s anemia and RLD. This anemia usually is not seen
in routine blood counts done as a newborn, and is identified
only by DEB (diepoxybutane) chromosome breaking testing.
VACTERL (vertebral anomalies, anal atresia, cardiac abnor­
malities, tracheoesophageal fistula, esophageal atresia, renal
Fig. 26.1  Limb bud coordinate axes and signaling centers.3
AER, Apical ectodermal ridge; Di, distal; Do, dorsal; Pr,
proximal; Rad, radial; Uln, ulnar; Vo, volar; ZPA, zone of
polarizing activity. (Redrawn after Oberg KC, Feenstra JM,
Manske PR, et al. Developmental biology and classification of
congenital anomalies of the hand and upper extremity. J Hand
Surg Am. 2010; 35:2066–2076.)
Dorsal Ectoderm
Do
Pr
Vo
Di
PZ
AER
AER
AER
Do
Rad
Vo
ZPA
Uln
Pr
Rad
PZ
ZPA
Uln
Di
PZ
Somites
Forelimb
Carnegie Stage 13 Embryo
Eye
Heart
A
B
C
D
Table 26.1  Modified classification of radial longitudinal deficiency.
Type
Thumb
Carpus
Distal radius
Proximal radius
N
Hypoplastic or absent
Normal
Normal
Normal
0
Hypoplastic or absent
Absence, hypoplasia, or coalition
Normal
Normal, radioulnar synostosis, or congenital
dislocation of the radial head
1
Hypoplastic or absent
Absence, hypoplasia, or coalition
>2 mm shorter
than ulna
Normal, radioulnar synostosis, or congenital
dislocation of the radial head
2
Hypoplastic or absent
Absence, hypoplasia, or coalition
Hypoplasia
Hypoplasia
3
Hypoplastic or absent
Absence, hypoplasia, or coalition
Physis absent
Variable hypoplasia
4
Hypoplastic or absent
Absence, hypoplasia, or coalition
Absent
Absent
(Adapted from James M, McCarroll R, Manske PR. The spectrum of radial longitudinal deficiency: a modified classification. J Hand Surg Am. 1999;24:1145–55.)

576
SECTION IV
CHAPTER 26 • Congenital hand II: Longitudinal, central, and transverse deficiency
Fig. 26.2  Thumb hypoplasia, types I to V: type I, hypoplastic type; type II, +
missing intrinsics; type IIIA, + missing extrinsics, stable carpometacarpal (CMC)
joint (circle); type IIIB, + unstable/missing CMC; type IV, pouce flottant; type V,
absent joint.22 (With permission from Herring JA, Tachdjian MO. Texas Scottish Rite
Hospital for Children. Tachdjian’s Pediatric Orthopaedics, 4th edn. Philadelphia, PA:
Saunders/Elsevier; 2008.)
Type I
Type II
Type IIIB
Type IIIA
Type IV
Type V
Extrinsic and
intrinsic present
Extrinsic present
intrinsic absent
Clinical tips
RLD – evaluation for surgery
• Careful evaluation of the entire patient.
• Scoliosis screening.
• Complete blood count, renal ultrasound, echocardiogram.
• +/− DEB test.
radius. The type V radius reflects a more proximal involve­
ment of the upper limb.
The hypoplastic thumb was classified as by Blauth (1967)
into types I–V.20 An important distinction was made by
Manske (1995) who introduced a type IIIA and type IIIB,
which has implications on the treatment offered to the patient
and family.21 Type I hypoplastic thumbs are a little smaller
than normal thumbs but possess all the structures usually
present in an unaffected thumb. As a result, they very rarely
need any surgical treatment. In type II thumbs, the thenar
musculature is poorly developed with associated adduction
contracture of the first ray and variable amounts of
metacarpal–phalangeal (MP) joint laxity. As hypoplasia pro­
gresses to type III, a loss of extrinsic musculotendinous units
is noted. Type III has been further subdivided into an A or B
depending on whether the carpometacarpal (CMC) joint is
stable.21 This has important ramifications on the type of
reconstruction that is performed. Type IV is the pouce flottant,
or floating thumb, and type V is an absent thumb.22 (Fig. 26.2).
Patient selection
Because of the appearance of the upper limb, the hand surgeon
may have early involvement in the care of the affected patient.
It is imperative that a thorough history is taken, as well as a
complete physical examination. This should include evalua­
tion of the lower extremities, hips, back, head and neck area,
as well as the upper extremities. In addition, because of the
possible associated anomalies, it is important to make sure the
patient has had a complete blood count (CBC), echocardio­
gram, and renal ultrasound. If a significant sacral dimple
(+/− hairy patch) was noted on examination, a spinal ultra­
sound is warranted to rule-out tethered cord. Obtaining a
DEB test at the time of initial evaluation is advocated by some,
because infants with Fanconi’s anemia have a normal CBC
and may not display signs of aplastic anemia until 3–4 years
of age or older.22 In the past, low incidence and high cost of
DEB testing argued against routinely obtaining it; however,
the advent of more successful treatment of these patients by
pediatric hematologists at earlier ages has made DEB testing
more routine in our practice.
Upper limb evaluation usually reveals some radial deviation
at the level of the wrist with some degree of thumb hypopla­
sia. It is important to note that the severity of the radial
hypoplasia does not necessarily correlate with degree of
thumb hypoplasia (Fig. 26.3A,B). In other words, a patient
with a type IV radius may have a type I hypoplastic thumb,
and vice versa. The physical examination should note the
motion at the shoulder, elbow, wrists, and fingers, with nota­
tion of the resting position of the radius and degree of passive
correction. Degree of thumb hypoplasia as well as the nature
of the fingers (supple or stiff) is also important to note in the

577
Radial longitudinal deficiency
systems can be affected in these patients, no surgery should
be contemplated until after medical clearance is obtained.
A common procedure for the wrist is distraction with some
variation of centralization, whether it be centralization or
radialization.25–33 In general terms, this involves surgically
placing the carpus on the distal end of the ulna. Centraliza­
tion, without distraction, was described by Sayre in 1893 with
multiple modifications being made over the years by other
surgeons.25 An important addition was by Kessler in 1989,
who introduced the concept of pre-distraction of the soft
tissues prior to centralization, as many surgeons noted diffi­
culty performing centralization without it because of the
severity of soft-tissue contractures.28 The age that this is per­
formed, as well as the speed of distraction, varies depending
on the surgeon.28,30,31,33 In the classic centralization procedure,
a notch is made in the carpus to align the third metacarpal
with the ulna. In the radialization procedure, described by
Buck-Gramcko, the carpus is balanced on the ulna with the
second metacarpal in alignment with the ulna.32 Dorsoradial
muscle mass is then transferred to the dorsoulnar side in an
attempt to re-balance the forces across the wrist. The greatest
problem with these procedures is that the wrist deformity
tends to recur over time,34 with potential for ulnar physeal
injury and ultimately a shorter forearm.23 Also, only one
published study has shown functional benefit of the proce­
dure,35 with most reporting no significant improvement using
validated outcome studies.24,36 In addition, as stated above, in
some patients elbow stiffness and/or ulnar prehension exists
which makes wrist radial deviation an advantageous position
for getting the hand to the mouth.
An alternative to centralization for severe cases (types III
and IV) is the soft-tissue release and bilobed flap procedure37
(Fig. 26.4). In this procedure the non-essential soft-tissue
initial evaluation. If the patient is a newborn, radiographs
may not be of much use and can usually wait until they are
seen at the 6–12 month-old time interval.
The role of the occupational therapist is crucial, as stretch­
ing of the wrist is begun when the newborn is first seen. When
the child is of adequate size, a splint is fashioned to aid in the
stretching of the wrist. On subsequent visits it is crucial to
observe and document the use-pattern of the fingers. In other
words, when the child grasps objects, is it between: thumb–
index finger (if thumb present); index–middle finger; or
ring–little finger? This becomes important when considering
surgical intervention, not only for the thumb but also the
wrist. If a child grasps primarily between the ring and little
fingers, any attempt to formally centralize the wrist (discussed
later) may actually worsen function as it may prevent the
child from getting his/her hand to the mouth. Also, it has
been shown in these patients that the average growth of the
ulna in an untreated patient is 64% of normal, with centralized
patients achieving only 48–58% of normal length, which can
further limit access of the hand to the mouth.23 Additionally,
in a recent article, Ekblom (2014) reported that in RLD patients,
grip strength, key pinch, forearm length, and elbow and
digital motion are more important than radial angulation of
the wrist for daily activity and participation.24
Surgical treatment and postoperative care
As the child reaches a year of age, he/she can be assessed for
suitability for surgical intervention. As stated above, some
patients actually benefit from having a radially deviated wrist
and would be greatly impaired if it was placed in a straight,
stiff position. Other important considerations include the
generalized health of the patient. As many associated organ
Fig. 26.3  (A) Type IV radius and type II hypoplastic thumb. (B) Type 0/N radius and type IV hypoplastic thumb.
A
B

578
SECTION IV
CHAPTER 26 • Congenital hand II: Longitudinal, central, and transverse deficiency
metadiaphysis to the radial carpus to prevent motion during
flap healing. This wire is carefully placed as to not cross the
ulnar physis. At 4 weeks, the wire is removed and a custom
static wrist orthosis is fashioned, with institution of range of
motion exercises and stretching. The orthosis is continued
full-time for 6 weeks, then transitioned to night-time use only.
It is understood that recurrence of some radial deviation at
the wrist is the anticipated outcome; however, it preserves
motion of the wrist with an improved resting position. In
addition, there is no potential for ulnar physeal injury, thereby
allowing the ulna to grow to its full potential, which, as stated
above, is approximately two-thirds of normal. In patients with
TAR syndrome, a significant elbow flexion contracture can be
present and can be effectively treated by releasing the so-called
brachiocarpalis muscle, which has been previously described.38
This muscle has a high origin on the humerus and inserts on
the radial carpus, thereby causing a significant elbow flexion
contracture along with deformity at the wrist. At a later time,
if the patient and family desire a straighter wrist position, a
Vilkki procedure can be offered as an alternative.39 (Fig.
26.5A,B) In this procedure, a distractor is placed and the hand
is gradually brought out, if not overcorrected, over a period
of 6 weeks. This can be a very difficult distraction as the
structures are released with use of a bilobed flap for skin
closure. Our original procedure involved a dorsal approach,
but we have now transitioned to a volar approach based on
several factors: improved, less conspicuous scars and better
exposure for identification and safe release of tight radial
structures. Under tourniquet control, the skin flaps are incised
and raised off the investing fascia. This dissection plane, in
addition to wide flap bases, preserves maximal blood supply
to the tips of the flaps. During dissection, the dorsal branch
of the ulnar nerve as well as sensory branches of the radial
nerve should be identified and preserved. At this point, all
tight fascial bands along the radial wrist are released. It is
important to not perform extensive dissection around the
distal ulna as it may compromise physeal blood flow and lead
to growth arrest. If a pure wrist flexor is identified inserting
into the radial carpus, it can be released and transferred to
the ulnar wrist. The median nerve and finger flexors can be
in a very aberrant location and must be carefully identified
and preserved. After this is performed, usually the wrist
can be brought to a neutral position in both the radial/
ulnar and extension/flexion axes. It is important to place a
Kirschner wire for stabilization with the wrist in maximum
correction which is directed obliquely from the distal ulnar
Fig. 26.4  Diagram of rotation for dorsal and volar bilobed flaps with corresponding clinical photographs.37 (Reproduced with permission from Vuillermin C, Wall L, Mills J,
et al. Soft tissue release and bilobed flap for severe radial longitudinal deficiency. J Hand Surg Am. 2015;40:894–9.)
Dorsal
Volar
Pre
Post
Pre
Post

579
Radial longitudinal deficiency
base of the proximal phalanx as well as the metacarpal neck.
Next, an incision is made along the radial side of the thumb,
exposing the radial metacarpal neck. A bone tunnel is then
made through the metacarpal neck/head area to allow the
FDS ring finger tendon to be passed through it. Next, an
incision is made over the A1 pulley of the ring finger, and the
FDS tendon is isolated and transected distally. An incision is
then made over the volar–ulnar wrist or the transverse carpal
ligament, depending on which pulley is to be utilized. The
FDS tendon is then retracted proximally and re-directed
around the desired pulley to the radial incision that had
already been made. If only the MP (metacarpal–phalangeal)
ulnar collateral ligament (UCL) is to be reconstructed, then
the entire tendon is passed through the bone tunnel and
across the joint to the ulnar base of the proximal phalanx. A
suture anchor or bone tunnel can be used, but it is obviously
essential to be distal to the proximal phalanx physis. If the
radial collateral ligament (RCL) also needs to be reconstructed,
then the tendon can be split: half passed through the bone
tunnel, while the other half is passed across the radial side of
the MP joint to reconstruct the RCL. The Z-plasty flaps are
deformity is not only radial but also volar. At this point, a
vascularized second metatarsal–phalangeal toe joint is trans­
ferred to the radial side of the distal forearm. (Fig. 26.6A,B)
The distraction device is left on another 6 weeks and then
removed. This results in a straighter wrist while preserving
wrist motion. However, we have found that most patients/
parents are satisfied with the soft-tissue release alone and do
not want to proceed with the toe joint transfer.
Surgical treatment options for the thumb
Type I hypoplastic thumbs have all the structures and thus do
not usually need reconstruction. Type II hypoplastic thumbs
usually can benefit from an opponensplasty +/− MP joint liga­
ment reconstruction if significant instability is present. I prefer
a flexor digitorum superficialis (FDS) ring transfer; however,
a Huber transfer (abductor digiti minimi) has also been used
to reconstruct opposition. (Fig. 26.7A–C) In addition, many of
these patients also benefit from a four-flap Z-plasty of the first
webspace. This is performed by first elevating the flaps for
the four-flap Z-plasty in the first web and exposing the ulnar
Fig. 26.5  (A) A 5 12-year-old male with RLD. (B) Initial surgery with bilobed flap/
soft-tissue release and distractor placement.
A
B

580
SECTION IV
CHAPTER 26 • Congenital hand II: Longitudinal, central, and transverse deficiency
deviation is present. A thorough evaluation of the patient is
warranted due to the many medical conditions that may also
be present. As the child approaches the age range of 12–18
months, consideration for surgery on the wrist can be under­
taken, if warranted, as long as underlying medical issues do
not preclude it. At about 2 years of age, index pollicization
can be performed if this is indicated. Tendon transfers/MP
stabilization procedures usually are not performed until the
child is older, in the range of 4–6 years old, as structures are
larger and rehabilitation easier and more effective. Genetic
counseling can be important for parents because of the many
associated syndromes and the varying inheritance patterns
that exist.
Ulnar longitudinal deficiency
Basic science/disease process
The incidence of ulnar longitudinal deficiency (ULD) is much
less than that of radial longitudinal deficiency, approximately
one-quarter, and usually is unilateral. In the Swanson classi­
fication, this represents a IB, and in the OMT classification it
is I.A.2.ii (upper limb including hand) or 2.ii (hand only).11 In
contradistinction to RLD, most cases of ULD are sporadic and
rarely have associated heart and hematopoietic abnormalities.
In addition, ULD patients can have musculoskeletal anoma­
lies such as fibular and tibial ray deficiency, proximal femoral
focal deficiency, scoliosis, clubfeet, and absent patellae, which
are not usually seen in RLD patients. Interestingly, radial
hand abnormalities are not infrequent. This is thought to be
due to an insult in the ZPA, which resides on the ulnar side
of the developing hand. Depending on the severity of the
insult, this can affect the development and growth of both
ulnar and radial hand structures.
Diagnosis/patient presentation
Bayne (1982) classified the forearm/elbow into four types
based on the length and size of the ulna. Type I is a hypoplastic
rotated and sutured in place. A pin is placed across the MP
joint with the patient in cast immobilization for 4 weeks. After
the 4-week period, the patient is then placed in a basic oppo­
nens splint, and range-of-motion (ROM) exercises instituted
with the splint gradually being weaned over a 4-week period.
Fig. 26.6  (A) 6 weeks post-distraction. (B) After graft incorporation (note the open physes of the toe transfer).
A
B
Clinical tips
RLD – considerations for thumb surgery
• Observe patient to ensure he/she attempts use of thumb
for pinch (i.e., does not bypass it), otherwise pollicization
may be the better procedure.
• Metacarpal must be large enough to allow bone tunnel to
be made.
• Patient must be able to participate in postoperative
rehabilitation.
• Avoid injury to the proximal phalanx physis when decided
on insertion point for FDS tendon.
In general, type IIIA thumbs benefit from reconstruction as
stated above; however, type IIIB thumbs require index finger
pollicization because of the gross instability of the CMC joint.
Type IV and V thumb hypoplasia is treated with an index
pollicization if warranted clinically. Prior to performing a
pollicization, it is important to observe the child’s prehensile
grasp. If he/she preferentially pinches between the index and
middle finger, then a pollicization is indicated (Fig. 26.8A–D).
If, however, the index finger is stiff and pinch is between the
ring and little finger, then pollicization will not likely improve
function. In some countries, because of cultural considerations,
a toe transfer is preferred over a pollicization.40 Extensive
details for thumb reconstruction can be found in Chapter 27.
Outcomes, prognosis, and complications
In summary, early treatment for patients with RLD includes
stretching and splinting of the wrist if significant radial

581
Ulnar longitudinal deficiency
is no correlation between the severity of ulna and hand
involvement.
Patient selection
As in any child with an upper limb anomaly, it is important
to perform a thorough examination from head to toe. As
stated above, lower extremity abnormalities can be present
in ULD and must be documented and appropriate referrals
made if present. In the upper limb, the hand can be in a
variety of positions, including facing backwards in some
cases of type IV ULD, but a significantly short extremity
is usually present. The elbow can be stable or unstable
depending on ulna involvement, with restricted or absent
forearm pronation/supination. The wrist may have some
ulna deviation but is usually stable. Oligodactyly in the
hand with varying degrees of deficiency in the fingers/
thumb that are present is the usual clinical scenario. This
can include underlying possible bony anomalies such as
metacarpal synostosis or aberrant bony anatomy of the
hand/fingers, which may represent further deforming forces.
Syndactyly may also be present to varying degrees in the
fingers.
ulna with proximal and distal ulnar epiphyses present.41
Minimal deformity or shortening is noted. Type II is absent
distal or middle third of ulna with possible fibrous anlage and
consequential radial bowing. However, the elbow is stable.
Type III is a total absence of the ulna with an unstable elbow.
Type IV is an absent ulna with radiohumeral synostosis. In
addition, there is possible progressive ulnar deviation at the
wrist secondary to a fibrous anlage, although this is contro­
versial.41 As in RLD, a type 0 has been added, to represent
patients who display hand plate abnormalities only.42 Also, as
in RLD, a type V has been added, to represent more proximal
involvement (phocomelic)19 (Fig. 26.9). Cole and Manske
(1997) classified the hand based on the appearance of the
thumb and first webspace as this is critical for hand function43
(Fig. 26.10). In type A, the thumb and first webspace are
normal. In type B, the thumb is mildly deficient with a narrow
first webspace. Opposition is present with intact extrinsic
tendons. In type C, there is a more severe first webspace
deficiency with varying degrees of thumb involvement,
including possible syndactyly to the index finger and malrota­
tion of the thumb into the plane of the palm. Opposition
function is lost and dysfunction of the extrinsic tendons is
present. Type D represents an absent thumb. As in RLD, there
Fig. 26.7  (A) Preoperative photographs of a type IIIA
hypoplastic thumb. (B) Intraoperative photograph of design of
opponensplasty. (C) Postoperative opposition and metacarpal–
phalangeal joint stability.
A
B
C

582
SECTION IV
CHAPTER 26 • Congenital hand II: Longitudinal, central, and transverse deficiency
A
B
C
D
Fig. 26.8  (A) Preoperative photograph and radiograph for pollicization (note the pronated position of the index finger). (B) Intraoperative photograph of design of incisions
along with photograph of final closure. (C) Postoperative function. (D) Postoperative radiograph showing good stability at the base and open physes of the pollicized digit.

583
Ulnar longitudinal deficiency
Fig. 26.9  Schematic of Bayne’s classification of ulnar longitudinal dysplasia.22,41
(Reproduced with permission from original publication: Herring JA, Tachdjian MO.
Texas Scottish Rite Hospital for Children. Tachdjian’s Pediatric Orthopaedics, 4th
edn. Philadelphia, PA: Saunders/Elsevier; 2008.)
Type IV
Type V
A
B
Type III
Type II
Humerus
Radius
Ulna
Type I
Clinical tips
ULD – evaluation for surgery
• Assess the child for proximal femoral focal deficiency,
fibular and tibial deficiency, scoliosis, clubfeet, and absent
patellae.
• Anomalies of the heart and hematopoietic systems are rare.
• The deficit in the hand can include ulnar, radial, or both
sides of the hand.
• Carefully assess the function of the hand as well as
radiographs since variable anatomy may be present and
separation of digits may not be warranted.
These children are usually of normal to above-normal intel­
ligence and function very well. At times, adaptive devices can
be very helpful with activities of daily living, and it is impera­
tive that therapists are involved with the care of these patients.
It should be noted that since these children are usually
extremely functional, any surgery that is contemplated
must have a specific goal to increase use/function prior to
proceeding.
Surgical treatment and postoperative care
While most ULD children are able to bring the hand to the
mouth, some type IV children (radiohumeral synostosis) have
his/her elbows fused in a position with the hand facing
backwards. These children can benefit from a flexion osteot­
omy to put the hand in a position to reach the mouth. Impor­
tantly, this is usually not a rotational osteotomy as clinically
it is apparent that most times the deformity is one of hyper­
extension, not rotation, based on the thumb position. The
osteotomy is usually performed in the supracondylar region
of the humerus. It is important to Doppler out and mark the
course of the brachial artery prior to surgery. Also, removal
of 1–2 cm of bone usually allows the osteotomy to be
Fig. 26.10  Bayne and Manske classifications for ulnar dysplasia. H, Humerus; R,
radius; U, ulna;* indicates progressive involvement of the thumb–index webspace.22
(Reproduced with permission from original publication: Herring JA, Tachdjian MO.
Texas Scottish Rite Hospital for Children. Tachdjian’s Pediatric Orthopaedics. 4th
edn. Philadelphia, PA: Saunders/Elsevier; 2008.)
Type IV
Type III
Type II
Type I
Bayne
Manske
A
B
C
D

584
SECTION IV
CHAPTER 26 • Congenital hand II: Longitudinal, central, and transverse deficiency
Fig. 26.11  (A) Preoperative
photograph and radiograph of ULD with
hand facing backwards. (B) Immediate
postoperative photograph, immediate
postoperative radiograph, and final
follow-up radiograph.
A
B
performed without undue tension on the neurovascular
structures, which is a potential serious complication. This
osteotomy can usually be stabilized with K-wires +/− intraos­
seous wire. It is then held immobilized until radiographic
evidence of union is noted (Fig. 26.11A,B). As expected, this
will usually improve function in these children as it enables
them to reach the hand to the mouth.
In some patients, release of the ulnar anlage can be benefi­
cial as it acts as a tether that can cause increasing deformity,
radial bowing, and ulnar wrist deviation as the child grows
(usually type II or IV). Interestingly, histology of this structure
has shown it to be hyaline cartilage proximally and fibrocar­
tilage more distally. Serial X-rays and clinical examinations
will determine the appropriate patients and timing for the
surgery as not all ULD patients will benefit from this. Of
note, this should be done when the patient still has significant
radial growth potential remaining, as release of the tether
will allow correction of much of the angular deformity over
time. To do this, an incision is made over the ulnar border
of the forearm/wrist with careful identification of the ulnar
neurovascular bundle, if present, as the flexor carpi ulnaris is
usually not present. It is essential to completely dissect out
and release the distal portion of the anlage which attaches to
the carpus and sometimes the radius. After this is performed,
the “tether” effect should be alleviated and passive motion
should be markedly improved. If severe bowing is present
or not much growth remains in the radius, then an oste­
otomy can be performed at the same setting. The extremity
is then casted until wound healing has taken place (bone
healing if osteotomy was performed) (Fig. 26.12A–C). Stretch­
ing and splinting is instituted along with serial follow-up
radiographs.
The majority of surgical procedures in ULD patients are
usually focused on the hand. Depending on the type of hand
deformity present, surgery can involve first webspace recon­
struction, syndactyly reconstruction, and/or thumb recon­
struction (Fig. 26.13A,B). It is imperative that a thorough
clinical and radiographic examination be performed prior to
contemplating any surgical reconstruction. Because of the
unusual anatomy that can exist, no syndactyly reconstruction
is warranted and/or feasible at times (Fig. 26.14A,B). Also,
when syndactyly reconstruction is undertaken, careful explo­
ration of the neurovascular and tendinous structures is war­
ranted since at times separation is not technically feasible.
First webspace reconstruction is accomplished either through
standard webspace deepening techniques or flap reconstruc­
tion in severe cases. A difficult situation exists when the
thumb is in the plane of the palm. Since opposition function
is so crucial in these patients, performing a rotational osteot­
omy through the metacarpal can be helpful. However, signifi­
cant memory in the periosteum and other deforming forces
can exist and can cause recurrence of the deformity. To address
these, the periosteum should be scored circumferentially as
well as a release and re-insertion of the adductor and thenars,
if present. At times, opposition transfer is also required to
provide enhanced function of the thumb.

585
Ulnar longitudinal deficiency
Fig. 26.12  (A) 10-month-old with ULD and severe deformity due to ulna tether. (B) Photograph depicting ulna anlage excision and osteotomy of same patient at 1 year of
age. (C) Follow-up at age 3 years (left) and 9 years (right) of age showing maintained longitudinal growth without recurrent deformity.
A
B
C
Fig. 26.13  (A) Preoperative photograph and radiograph of ULD patient with syndactyly. (B) Postoperative photograph and radiograph.
A
B
Fig. 26.14  (A) Preoperative photograph and radiograph of ULD patient not suitable for syndactyly separation, but rather rotational thumb osteotomy alone. (B) Immediate
postoperative photograph of rotational osteotomy of thumb with no syndactyly release.
A
B

586
SECTION IV
CHAPTER 26 • Congenital hand II: Longitudinal, central, and transverse deficiency
Split-hand/split-foot syndrome also has an autosomal-
dominant inheritance pattern with variable penetrance.
Diagnosis/patient presentation
In the original IFSSH classification, this was I.B.3. In the OMT
classification, cleft hand is 3.11.c. Manske (1995) published a
classification that is useful in guiding treatment in these
patients.46 His classification is based on the first webspace:
type 1, normal web; type 2A, thumb web mildly narrowed;
type 2B, thumb web severely narrowed; type 3, syndactylized
web; type 4, thumb web merged with cleft with index finger
suppressed; and type 5, absent thumb and web suppressed
with ulna ray remaining.46
Patient selection
Because of the phenotypic variability, it is imperative to
examine the entire patient. Classically, the cleft deformity in
the hands and feet has been described as “V” shaped; but in
the monodactylous form, only the ulnar digit may be present.
Syndactyly between digits adjacent to the cleft is common, as
is variable metacarpal and phalangeal anatomy. Evaluation of
ectodermal-derived structures is also important because of
possible EEC syndrome. Radiographs yield important infor­
mation regarding underlying bony abnormality as well as
possible presence of aberrant osseous structures.
As in other patients with congenital hand differences,
therapists are essential members of the team as they provide
teaching as well as assistive devices if necessary.
Surgical treatment and postoperative care
Adrian Flatt commented that these patients are “a functional
triumph and social disaster”, meaning that these patients are
very functional and any considerations for surgery should
take this into account, especially when deciding to operate on
Outcomes, prognosis, and complications
ULD is less common than RLD and is distinguished from it
in several important ways. As opposed to RLD, patients with
ULD usually do not have associated cardiac, renal, gastro­
intestinal, or hematopoietic abnormalities. Instead, they can
have associated musculoskeletal abnormalities and, therefore,
a thorough lower extremity exam is warranted. Surgical treat­
ment is usually centered on issues present in the hand includ­
ing webspace insufficiency, syndactyly, and/or thumb (if
present) position.
Central deficiency
Basic science/disease process
The etiology of central deficiency is thought to be a defect in
the AER, which has been reproduced in the chick embryo by
removing the central portion.44 Of note, complex polysyndac­
tyly and central deficiency are two phenotypes that can result
from the same teratogen, and are thus related. This has been
shown in eloquent experiments by Ogino (1990), who gave
busulfan to a litter of rats, which resulted in both phenotypes
(Fig. 26.15). A logical explanation for the sequence of this
exists in his paper and is beyond the scope of this chapter.45
Autosomal-dominant inheritance pattern is present in
many patients, and has been localized to chromosomes 3, 7,
and 10. However, de novo mutations are also quite common.
An interesting inherited central deficiency is EEC (ectrodac­
tyly ectodermal dysplasia, cleft lip/palate), which has been
localized to 7q11.2–q21.3. In this syndrome, central deficien­
cies can be present in all four limbs as well as cleft lip/palate,
sparse and brittle hair, external ear abnormalities, hearing
loss, ophthalmologic abnormalities, and genitourinary prob­
lems, although phenotypic expression is highly variable.
Fig. 26.15  Cleft hand and central synpolydactyly hand in same patient.

587
Transverse deficiencies
wires, or a combination of both. If a third metacarpal is not
present, an osteotomy at the base of the index metacarpal can
help with re-positioning the finger in the plane of the ring and
little finger. In either case, reconstruction of an intermetacarpal
ligament is performed using bone tunnels and local tissue
such as A1 pulleys, free tendon graft, or a combination of
these.
In cases of central clefts with a normal thumb–index web,
closure can be performed with local flaps producing good
results in terms of function and aesthetic appearance. Usually
transposition of the metacarpal is warranted as well as recon­
struction of the intermetacarpal ligament using localized
tissue or graft.
In some cases, no separation/closure should be performed
since the function is good and any attempts at separation and
transposition may actually make the digits unstable.
In cases of four-limb involvement, where the pediatric
orthopedists are planning Symes amputation, consideration
should be given to use of toes as a potential transfer to the
hand, if indicated, to improve overall function, especially if a
type 5 cleft (absent thumb) is present.
Outcomes, prognosis, and complications
In summary, it is imperative that every patient be evaluated
separately and decisions regarding surgical intervention be
made on a case-by-case basis. Surgery should be reserved for
patients in whom improved function and cosmetic appear­
ance can be achieved with minimal potential morbidity. If
patients are not selected appropriately, poor outcomes along
with significant scarring can occur.
Transverse deficiencies
Basic science/disease process
As mentioned earlier, this condition is thought to be caused
by disruption of the subclavian vascular axis as described by
Bavinck and Weaver.6 They hypothesize that occlusions occur
at specific locations around the sixth week of embryonic
a cleft solely for cosmetic reasons.47 Certainly Manske’s clas­
sification offers generalized principals for treatment based on
the importance of the first webspace for grasp. Creating an
adequate first webspace certainly provides increased grasp
and is of significant benefit to the patient. Depending on
underlying anatomy, the thumb–index fingers may be better
left together, based on clinical examination and radiographic
appearance.
At times there can be a transverse bone present in cleft
hands and, if not addressed, this can be a significant deform­
ing force as the child grows (Fig. 26.16). Excision at the base
of the transverse bone should ensure removal of potential
physis of the transverse bone to decrease risk of recurrence.
In addition, underlying structures such as the collateral liga­
ments may need to be repaired/reconstructed after removal
of the transverse bone.
If thumb–index finger release is to be performed along with
cleft closure (types 2B and 3), many techniques have been
described. Popular skin incision designs that are utilized
include Snow–Littler,48 Miura–Komada,49 and more recently
Upton.50 I prefer a slightly modified version of Upton, as the
design is much simpler and the risk of wound problems is
much less than that seen in the Snow–Littler and Miura–
Komada procedures (Fig. 26.17A–C). After the skin incisions
are made, meticulous technique must be utilized to preserve
vascularity of the skin flaps, as partial or moderate skin flap
loss can be a frequent complication. No matter which incision
is used, it is imperative that thorough exploration of the
neurovascular structures is performed to assure the anatomy
will allow transposition and closure of the cleft without undue
risk to the digit. Also, assessment of the adductor muscle
insertion is essential and re-positioning performed, if war­
ranted, as it sometimes is attached to the index finger. Fascia
and other aberrant muscle may also need to be released in
order to adequately release the first web. After this is per­
formed, transposition of the index metacarpal to the middle
metacarpal is performed if technically feasible. The origin of
the adductor muscle off the middle metacarpal is carefully
identified and preserved, with the index metacarpal being
transposed just distal to this point after adjusting for appro­
priate length. This can be stabilized with K-wires, interosseous
Fig. 26.16  Cleft hand with transverse
element.

588
SECTION IV
CHAPTER 26 • Congenital hand II: Longitudinal, central, and transverse deficiency
system. In the OMT system, this is I.A.1.ii(a,b) for whole limb
or I.B.1.ii for hand plate alone without forearm/arm involve­
ment.11 The diagnostic phenotype shows great diversity,
including short-finger type, monodactylous type, atypical
type, and peromelic type. As opposed to patients with central
deficiency which have a “V” deformity, these patients display
a “U” deformity along with nubbins (remnants of ectoderm).
Interestingly, Poland’s is usually seen more commonly with
the short-finger variant than with the peromelic type.
Patient selection
Examination of these patients should begin in the head and
neck region to assess for possible Moebius syndrome. Next, a
careful examination of the neck and trunk for clinical evidence
of Klippel–Feil, Sprengel’s, and/or Poland’s is warranted. In
children with Poland’s, the findings can be solely a lack of the
sternal head of the pectoralis major or be the entire muscle
with involvement of the chest wall with involvement of the
pectoralis minor and latissimus dorsi muscles. In infants, it
can be very difficult to identify the very mild cases of Poland’s
and reassessment at a later date is necessary. The findings in
the upper extremity can be divided into four types: (1) short-
finger type, (2) monodactylous type, (3) atypical cleft type,
and (4) peromelic type (Fig. 26.19A–D). In patients with the
peromelic type, the level of truncation can be the hand, carpus,
development. Depending on the timing and location of the
insult, different phenotypes may arise. In addition, there may
be associated findings of Poland’s (varying amounts of pec­
toralis muscle absence), Moebius syndrome, Klippel–Feil, and
even Sprengel deformity.6
No animal model has been developed that re-creates this
deformity. This is usually a sporadic occurrence that presents
unilaterally. Four-limb transverse deficiency associated with
aplasia cutis congenita is the exception (Adams–Oliver) and
can have either an autosomal-dominant or recessive inheri­
tance pattern.
An interesting transverse deficiency has been reported
from our institution that we feel has a different etiology than
symbrachydactyly.51 The phenotypical presentation is that
of a transverse deficiency with no ectodermal elements in
affected digits. Instead, fleshy bulbous soft-tissue sleeves are
present, and the severity seems to be most on the ulnar side
of the hand (Fig. 26.18). Because of the lack of ectodermal
elements and involvement pattern, we feel that this represents
a different etiology than the more commonly occurring sym­
brachydactyly (subclavian artery supply disruption sequence).
Diagnosis/patient presentation
This is one of the diagnoses that did not clearly fit into any of
the categories that Swanson described in his classification
Fig. 26.17  (A) Preoperative photograph and radiograph of a cleft hand. (B) Intraoperative photographs and follow-up radiograph. (C) Final follow-up radiograph.
A
B
C

Fig. 26.18  Hypodactylia (note the lack of ectodermal elements).
A
B
C
Fig. 26.19  (A) Short finger symbrachydactyly. (B) Monodactylous symbrachydactyly. (C) Atypical
symbrachydactyly. (D) Peromelic symbrachydactyly.
D

590
SECTION IV
CHAPTER 26 • Congenital hand II: Longitudinal, central, and transverse deficiency
Fig. 26.20  Adaptive devices for activities.
to suit the needs of the child and enable them to more easily
perform activities such as jumping rope, riding bikes, and
sports (Fig. 26.20).
Surgical treatment and postoperative care
Parents of patients with the peromelic type of symbrachydac­
tyly can occasionally desire removal of the nubbins for cos­
metic reasons or because they frequently get traumatized. In
my experience, this is a rare occurrence and most parents
prefer to leave the nubbins and let the child make their own
decision when they are older regarding excision. At that time
it is extremely rare that they desire any surgery for this.
Short-finger type symbrachydactyly patients often have
webspaces that can benefit from deepening. The timing of this
depends on the severity and webspaces involved. In general,
because of the new reports of potential harm from general
anesthesia in young patients, we try not to perform this
surgery until after 2 years of age.54 Exceptions would be if
significant tethering of digits is present and/or significant
first webspace narrowing, in which case surgery would be
performed at an earlier age. If the middle phalanges are
severely hypoplastic, it is important to discuss with the
parents that even after separation the fingers may not have
full range of motion, so that they have realistic expectations.
Non-vascularized toe phalanx transfer has been advocated
by some in certain forms of symbrachydactyly to provide
more length to the fingers.55 In this procedure, portions of toe
phalanges, including periosteum, are transferred to soft-tissue
sleeves in the hand to provide more length. This must be
performed at a very young age for optimal results. Despite
some encouraging results, long-term studies show variable
amounts of reabsorption along with significant donor site
morbidity56 (Fig. 26.21). Due to our own experience, and that
of others, we are not advocates of this procedure.
Free vascularized toe transfers can be extremely beneficial
to patients with the monodactylous form of symbrachydac­
tyly, as it adds an ulnar digit which can provide increased
grasp capabilities (Fig. 26.22). In this procedure, usually the
second toe is harvested and transferred using standard
or forearm, with nubbins being present distally. Ogino (1989)
reported the order of radiographic findings found in the
progression of symbrachydactyly. The most common finding
in all types was hypoplasia of the central rays followed by
progressive brachymesophalangia leading to absence of
middle phalanges then more proximally to include metacar­
pals.52 Many times, the middle phalanx hypoplasia can be
significant enough to affect joint motion at the proximal
interphalangeal and distal interphalangeal joints. Even in
severe forms of symbrachydactyly (peromelic), nubbins con­
sisting of nail and underlying distal phalanx are present as
these are derived from ectodermal tissue.
Clinical tips
Transverse deficiencies – evaluation for surgery
• Clinical evaluation of the entire patient is necessary as
multiple associated findings may exist.
• It is important to remember that untreated patients function
very well, so any surgery, except syndactyly reconstruction,
needs to be assessed on an individual case basis and
should only be performed if there is a realistic goal of
increasing function.
• If a syndactyly exists but the finger tips are separated and
no significant tethering exists, reconstruction should be
delayed until the child is 2–3 years of age as to minimize
possible effects of anesthesia as well as to allow the fingers
to be bigger and easier to perform surgery on.
Surprisingly, these patients usually have very few limitations,
even with the most severe form. Most do not benefit from
prostheses as they are most commonly passive, insensate
devices and actually impair function in these children. For
patients and parents that are interested, reports of 3D-printer
prostheses have emerged and initial data is promising as a
cheaper alternative to myoelectric devices, which can be
very costly.53 Prostheses made to aid with specific activities,
however, can be very useful. These are usually custom-made

591
Transverse deficiencies
microvascular techniques to the ulnar side of the hand in a
position that allows tip-to-tip pinch with the thumb. Flexor
function of the transferred digit can be very difficult to achieve
as the recipient flexor tendons tend to be coalesced together
in the distal wrist/carpal tunnel region. As stated above, these
patients are usually very functional with very few limitations
and they (along with parents) usually do not desire to pursue
this procedure.
Patients with Poland’s present a very difficult problem for
the reconstructive surgeon. Some patients do not like the lack
of fullness in the anterior axillary fold as they feel it draws
unwanted attention and also limits what can be worn due to
the asymmetry. In these children, I assess them for presence
of ipsilateral latissimus dorsi muscle and, if present, discuss
potential rotational flap to address this. In the young child,
this can be performed with very limited incisions, thereby
having limited morbidity. In my experience, this has yielded
excellent results and happy patients/parents. In patients/
parents that are interested, I perform this procedure at the age
of 8–10 years. Girls present a very difficult reconstruction, as
not only do they require breast reconstruction, but also the
Fig. 26.21  Patient who underwent non-vascularized toe transfer to the right hand
(left) with bone graft resorption and poor donor site (right).
Fig. 26.22  (A) Preoperative photograph and radiograph of monodactylous symbrachydactyly. (B) Postoperative
photograph exhibiting useful function along with a postoperative radiograph following vascularized toe transfer.
(C) Donor site following toe harvest.
A
B
C

592
SECTION IV
CHAPTER 26 • Congenital hand II: Longitudinal, central, and transverse deficiency
remember, however, that untreated patients are very func­
tional, so any surgical intervention is largely cosmetic in
nature and must not inhibit or worsen function.
As stated earlier, prosthetic hands/arms in the past have
been of very little functional use for congenital upper
extremity-absence patients, as they have been insensate and
non-functional. Recently there have been significant advances
in the development of functional myoelectric prostheses fol­
lowing traumatic amputation that may be of some value to
selected congenital absence patients in the future.58,59 However,
these tend to be very costly, and recently there have been
reports of 3D printing being a cheaper alternative.53
Although vascularized composite allografting (VCA) has
become more accepted, its significant morbidities make it
unlikely to become commonplace treatment for these patients.
Perhaps tissue engineering for generation/regeneration of
fingers/limbs may be a possible alternative if cell expansion
can be perfected to the point of making it a viable option;
however, this is likely many years away.60
Longitudinal, central, and transverse deficiencies are diag­
noses that are treated often by the pediatric hand surgeon. It
is imperative that the surgeon treating these conditions is
knowledgeable regarding the proper work-up that should be
performed for each condition, as well as appropriate referrals
and genetic counseling that should be obtained. These patients
are usually seen and treated from infancy until adulthood and
thus go through many stages of physical and psychological
development, which must be addressed. In fact, some of the
social issues far outweigh any decision-making regarding
surgery. These patients are usually very functional, so careful
consideration before proceeding with surgery is warranted.
Lastly, it is imperative to have a multidisciplinary team to
properly evaluate and treat these children as their needs are
certainly not static or identical in nature.
nipple is usually severely hypoplastic and in an aberrant
location. In early teenage years, an expander can be placed
with serial expansion until adulthood, at which point replace­
ment with a permanent implant is performed along with
nipple repositioning/reconstruction.
Outcomes, prognosis, and complications
Phenotypic variation is common in patients with transverse
deficiency. Treatment depends on what, if any, deformity is
present and can range from syndactyly reconstruction to free
vascularized toe transfer. These patients usually are very
functional and have an excellent long-term prognosis.
Future directions
For now, even though many RLD patients have genetic muta­
tions that can be identified, it is hard to believe that any
genetic manipulation is on the horizon that can alter the
phenotypical presentation, as upper extremity development
occurs very early in gestation. Likely alternative procedures
that provide stability and position of the wrist with retained
motion long term are possibly in our near future. Perhaps this
will include a variation of the procedure Innocenti57 uses for
reconstruction after tumor excision in the distal radius. He
utilizes a vascularized fibular head, which provides potential
benefits of good stability of the wrist, retained motion, and
growth potential, which is likely similar to that of the ulna. In
addition, a portion of the biceps tendon can be taken with
the fibular head to be used for ligamentous reconstruction
in the wrist. At this point, the potential complication of
peroneal nerve injury has limited its use. However, with
improved dissection techniques and anatomical studies, this
risk is likely to be decreased in the future. It is important to
2. Daluiski A, Yi SE, Lyons KM. The molecular control of upper
extremity development: implications for congenital hand anomalies.
J Hand Surg Am. 2001;26:8–22. Upper limb embryology is a very
complex process which requires a precise series of events to occur.
Knowledge of the normal sequence of events is imperative to
understanding the etiology of congenital upper limb differences and thus
be able to confer proper information to parents.
5. Kato H, Ogino T, Minami A, Ohshio I. Experimental study on radial
ray deficiency. J Hand Surg [Br]. 1990;15:470–476. This is an important
reference as it provides an animal model for radial longitudinal deficiency.
In this study the authors were able to reproduce radial longitudinal
deficiency by the administration of a teratogen at a specific time during
fetal development.
6. Bavinck JN, Weaver DD. Subclavian artery supply disruption
sequence: hypothesis of a vascular etiology for Poland, Klippel-Feil,
and Möbius anomalies. Am J Med Genet. 1986;23:903–918.
Symbrachydactyly is a very common congenital hand anomaly. At
present, no animal model exists for this condition, but in this reference the
authors describe the accepted etiology for symbrachydactyly as well as its
associated conditions.
11. Tonkin MA, Tolerton SK, Quick TJ, et al. Classification of congenital
anomalies of the hand and upper limb: development and
assessment of a new system. J Hand Surg Am. 2013;38:1845–1853.
24. Ekblom AG, Dahlin L, Rosenberg HE, et al. Hand function in adults
with radial longitudinal deficiency. J Bone Joint Surg Am.
2014;96:1178–1184.
33. Goldfarb CA, Murtha Y, Gordon JE, et al. Soft-tissue distraction
with a ring external fixator before centralization for radial
longitudinal deficiency. J Hand Surg Am. 2006;31:952–959.
37. Vuillermin C, Wall L, Mills J, et al. Soft tissue release and bilobed
flap for severe radial longitudinal deficiency. J Hand Surg Am.
2015;40:894–899.
39. Vilkki SK. Vascularized metatarsophalangeal joint transfer for radial
hypoplasia. Semin Plast Surg. 2008;22:195–212.
45. Ogino T. Teratogenic relationship between polydactyly, syndactyly,
and cleft hand. J Hand Surg [Br]. 1990;15:201–209. This is a landmark
reference as the author showed that in an animal model he could create
either polysyndactyly or cleft hand using the same teratogen given at the
same time during fetal development. Further, an excellent explanation is
given that explains how this can occur.
46. Manske PR, Halikis MN. Surgical classification of central deficiency
according to the thumb web. J Hand Surg Am. 1995;20:687–697.
Classification of central deficiency with its surgical implications.
Access the complete reference list online at

592.e1
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2. Daluiski A, Yi SE, Lyons KM. The molecular control of upper
extremity development: implications for congenital hand anomalies.
J Hand Surg Am. 2001;26:8–22. Upper limb embryology is a very
complex process which requires a precise series of events to occur.
Knowledge of the normal sequence of events is imperative to
understanding the etiology of congenital upper limb differences and thus
be able to confer proper information to parents.
3. Zaleske DJ. Development of the upper limb. Hand Clin.
1985;1:383–390.
4. Ogino T, Kato H. Clinical and experimental studies on ulnar ray
deficiency. Handchirur Mikrochir Plast Chir. 1988;20:330–337.
5. Kato H, Ogino T, Minami A, Ohshio I. Experimental study on radial
ray deficiency. J Hand Surg [Br]. 1990;15:470–476. This is an important
reference as it provides an animal model for radial longitudinal deficiency.
In this study the authors were able to reproduce radial longitudinal
deficiency by the administration of a teratogen at a specific time during
fetal development.
6. Bavinck JN, Weaver DD. Subclavian artery supply disruption
sequence: hypothesis of a vascular etiology for Poland, Klippel-Feil,
and Möbius anomalies. Am J Med Genet. 1986;23:903–918.
Symbrachydactyly is a very common congenital hand anomaly. At
present, no animal model exists for this condition, but in this reference the
authors describe the accepted etiology for symbrachydactyly as well as its
associated conditions.
7. Lourie GM, Lins RE. Radial longitudinal deficiency. A review and
update. Hand Clin. 1998;14:85–99.
8. Koskimies E, Lindfors N, Gissler M, et al. Congenital upper limb
deficiencies and associated malformations in Finland: a population-
based study. J Hand Surg. 2011;36:1058–1065.
9. Urban MA, Osterman AL. Management of radial dysplasia. Hand
Clin. 1990;6:589–605.
10. Swanson AB. A classification for congenital limb malformations.
J Hand Surg Am. 1976;1:8–22.
11. Tonkin MA, Tolerton SK, Quick TJ, et al. Classification of congenital
anomalies of the hand and upper limb: development and
assessment of a new system. J Hand Surg Am. 2013;38:1845–
1853.
12. Bonnet D, Terrett J, Pequignot-Viegas E, et al. Gene localization in
12q12 in Holt-Oram atrio-digital syndrome. Arch Mal Coeur Vaiss.
1995;88:661–666.
13. Lamb DW. Radial club hand. A continuing study of sixty-eight
patients with one hundred and seventeen club hands. J Bone Joint
Surg Am. 1977;59:1–13.
14. Verloes A, Frikiche A, Gremillet C, et al. Proximal phocomelia and
radial ray aplasia in fetal valproic syndrome. Eur J Pediatr.
1990;149:266–267.
15. Lindhout D, Stewart PA, Reuss A, et al. Prenatal ultrasound
in antiepileptic drug exposure (abstract). Teratology. 1988;37
:473–474.
16. Pauli RM, Feldman PF. Major limb malformations following
intrauterine exposure to ethanol: two additional cases and literature
review. Teratology. 1986;33:273–280.
17. Bayne LG, Klug MS. Long-term review of the surgical treatment of
radial deficiencies. J Hand Surg Am. 1987;12:169–179.
18. James M, McCarroll R, Manske PR. The spectrum of radial
longitudinal deficiency: a modified classification. J Hand Surg Am.
1999;24:1145–1155.
19. Goldfarb CA, Manske PR, Busa R, et al. Upper-extremity
phocomelia reexamined: a longitudinal dysplasia. J Bone Joint Surg
Am. 2005;87:2639–2648.
20. Blauth W. The hypoplastic thumb. Arch Orth Unfallchir.
1967;62:225–246.
21. Manske PR, McCarroll HR Jr, James M. Type III-a hypoplastic
thumb. J Hand Surg Am. 1995;20:246–253.
22. Kozin SH. Upper-extremity congenital anomalies. J Bone Joint Surg
Am. 2003;85-A:1564–1576.
23. Sestero A, Van Heest A, Agel J. Ulnar growth patterns in radial
longitudinal deficiency. J Hand Surg Am. 2006;31:960–967.
24. Ekblom AG, Dahlin L, Rosenberg HE, et al. Hand function in adults
with radial longitudinal deficiency. J Bone Joint Surg Am.
2014;96:1178–1184.
25. Sayre RH. A contribution to the study of club-hand. Trans Am
Orthop Assoc. 1893;6:208–216.
26. Manske PR, McCarroll HR Jr, Swanson K. Centralization of the
radial club hand: an ulnar surgical approach. J Hand Surg Am.
1981;6:423–433.
27. Watson HK, Beebe RD, Cruz NI. A centralization procedure for
radial clubhand. J Hand Surg Am. 1984;9:541–547.
28. Kessler I. Centralization of the radial club hand by gradual
distraction. J Hand Surg [Br]. 1989;14:37–42.
29. Tonkin MA, Nanchahal J. An approach to the management of radial
longitudinal deficiency. Ann Acad Med Singapore. 1995;24(suppl
4):101–107.
30. Smith AA, Greene TL. Preliminary soft tissue distraction
in congenital forearm deficiency. J Hand Surg Am. 1995;20:
420–424.
31. Nanchahal J, Tonkin MA. Pre-operative distraction lengthening
for radial longitudinal deficiency. J Hand Surg [Br]. 1996;21:
103–107.
32. Buck-Gramcko D. Radialization as a new treatment for radial club
hand. J Hand Surg Am. 1985;10:964–968.
33. Goldfarb CA, Murtha Y, Gordon JE, et al. Soft-tissue distraction
with a ring external fixator before centralization for radial
longitudinal deficiency. J Hand Surg Am. 2006;31:952–959.
34. Damore E, Kozin SH, Thoder JJ, et al. The recurrence of deformity
after surgical centralization for radial clubhand. J Hand Surg Am.
2000;25:745–751.
35. Kotwal PP, Varshney MK, Soral A. Comparison of surgical
treatment and nonoperative management for radial longitudinal
deficiency. J Hand Surg Eur Vol. 2012;37:161–169.
36. Holtslag I, van Wijk I, Hartog H, et al. Long-term functional
outcome of patients with longitudinal radial deficiency: cross-
sectional evaluation of function, activity, and participation. Disabil
Rehabil. 2013;35:1401–1407.
37. Vuillermin C, Wall L, Mills J, et al. Soft tissue release and bilobed
flap for severe radial longitudinal deficiency. J Hand Surg Am.
2015;40:894–899.
38. Oishi SN, Carter P, Bidwell T, et al. Thrombocytopenia absent
radius syndrome: presence of brachiocarpalis muscle and its
importance. J Hand Surg Am. 2009;34:1696–1699.
39. Vilkki SK. Vascularized metatarsophalangeal joint transfer for radial
hypoplasia. Semin Plast Surg. 2008;22:195–212.
40. Tan JS, Tu YK. Comparative study of outcomes between
pollicization and microsurgical second toe-metatarsal bone transfer
for congenital radial deficiency with hypoplastic thumb. J Recon
Microsurg. 2013;29:587–592.
41. Bayne LG. Ulnar club hand (ulnar deficiencies). In: Green DP, ed.
Operative Hand Surgery. New York: Churchill Livingstone;
1982:245–257.
42. Havenhill TG, Manske PR, Patel A, et al. Type 0 ulnar longitudinal
deficiency. J Hand Surg Am. 2005;30:1288–1293.
43. Cole RJ, Manske PR. Classification of ulnar deficiency according to
the thumb and first web. J Hand Surg Am. 1997;22:479–488.
44. Kosher RA, Savage MP, Chan SC. In vitro studies on the
morphogenesis and differentiation of the mesoderm adjacent to the
apical ectodermal ridge of the embryonic chick limb-bud. J Embryol
Exp Morphol. 1979;50:7–97.
45. Ogino T. Teratogenic relationship between polydactyly, syndactyly,
and cleft hand. J Hand Surg [Br]. 1990;15:201–209. This is a landmark
reference as the author showed that in an animal model he could create
either polysyndactyly or cleft hand using the same teratogen given at the
same time during fetal development. Further, an excellent explanation is
given that explains how this can occur.

592.e2
SECTION IV
CHAPTER 26 • Congenital hand II: Longitudinal, central, and transverse deficiency
46. Manske PR, Halikis MN. Surgical classification of central deficiency
according to the thumb web. J Hand Surg Am. 1995;20:687–697.
Classification of central deficiency with its surgical implications.
47. Flatt AE. The Care of Congenital Hand Anomalies. 2nd ed. St. Louis,
MO: Quality Medical Publishing; 1994.
48. Snow J, Littler J. Surgical treatment of cleft hand. In: Transactions of
the Society of Plastic and Reconstructive Surgery: 4th Congress in
Rome. Amsterdam: Exerpta Medica Foundation; 1967:888–893.
49. Miura T, Komada T. Simple method for reconstruction of the cleft
hand with an adducted thumb. Plast Reconstr Surg. 1979;64:65–67.
50. Upton J, Taghinia A. Correction of the typical cleft hand. J Hand
Surg Am. 2010;35:480–485.
51. Knight JB, Pritsch T, Ezaki M, Oishi SN. Unilateral congenital
terminal finger absences: a condition that differs from
symbrachydactyly. J Hand Surg Am. 2012;37(1):124–129.
52. Ogino T, Minami A, Kato H. Clinical features and roentgenograms
of symbrachydactyly. J Hand Surg [Br]. 1989;14:303–306.
53. Gretsch KE, Lather HD, Peddada KV, et al. Development of novel
3D-printed robotic prosthetic for transradial amputees. Prosthet
Orthot Int. 2016;40:400–403.
54. Aker J, Block RI, Biddle C. Anesthesia and the developing brain.
AANA J. 2015;83:139–147.
55. Cavallo AV, Smith PJ, Morley S, et al. Non-vascularised free toe
phalanx transfers in congenital hand deformities – the Great
Ormond Street experience. J Hand Surg [Br]. 2003;28:520–527.
56. Tonkin MA, Deva AK, Filan SL. Long term follow-up of composite
non-vascularized toe phalanx transfers for aphalangia. J Hand Surg
[Br]. 2005;30:452–458.
57. Innocenti M, Delcroix L, Manfrini M, et al. Vascularized proximal
fibular epiphyseal transfer for distal radial reconstruction. J Bone
Joint Surg Am. 2004;86-A:1504–1511.
58. Datta D, Ibbotson V. Powered prosthetic hands in very young
children. Prosthet Orthot Int. 1998;22:150–154.
59. Cheesborough JE, Smith LH, Kuiken TA, et al. Targeted muscle
reinnervation and advanced prosthetic arms. Semin Plast Surg.
2015;29:62–72.
60. Weinand C, Gupta R, Weinberg E, et al. Toward regenerating a
human thumb in situ. Tissue Eng Part A. 2009;15:2605–2615.

SECTION IV • Congenital Disorders
27 
Congenital hand III: Thumb hypoplasia
Amir Taghinia and Joseph Upton III
SYNOPSIS
■ The thumb ray is the prime ray of the hand – its size, position,
mobility, independence, and relations to the other digits are critical to
function.
■ The thumb is considered hypoplastic if any portion of the ray, skeletal
or soft tissue, is deficient or absent.
■ Growth and function of the thumb in the first year of life follows a
predictable pattern.
■ Although new procedures have expanded options for reconstruction,
standard procedures such as first webspace deepening, tendon
transfers, and collateral ligament reconstruction remain the best
options for treatment.
■ Pollicization continues to be the treatment of choice for severe
hypoplasia with a non-functional carpometacarpal joint, the floating
thumb, or the absent thumb.
■ Associated conditions of thumb hyperplasia include VACTERL, Fanconi
anemia and other hematologic abnormalities, Holt–Oram syndrome,
and thrombocytopenia absent radius (TAR) syndrome.
Access the Historical perspective section online at

Introduction
The hypoplastic thumb represents a wide spectrum of func­
tional and aesthetic differences. Before classification and
management of the deficient thumb, a careful surgeon must
assess its: (1) size; (2) position; (3) relation to other fingers of
the hand; (4) osseous components; (5) joint integrity and sta­
bility; (6) intrinsic and extrinsic musculotendinous units; (7)
first webspace depth and width; (8) associated malformations
of the hand and elsewhere; and (9) functional consequences
for the child. A thumb should be considered hypoplastic when
there is a deficiency of any one or all structures that contribute
to the “normal” thumb. In the past, all definitions were
restricted to the radiographic appearance alone; however,
presently, we understand that soft-tissue deficiencies also
contribute to the overall diagnosis.
For the first 3 months of life, the thumb is adducted and
flexed within the palm and serves primarily as a pacifier.
However, by 9 months of age, this first ray gains its indepen­
dence and mobility from the palm, and at 1 year of age, it has
become a crucial portion of the hand.15 In the normal hand,
the strength and mobility needed for a wide variety of pinch
and grasp functions rapidly develop, and by the time the baby
is ambulatory, the thumb is used creatively and independently
to manipulate the environment.
As relied upon in the past, a complete evaluation of the
osteoarticular column will require plain radiographs. Normal
primary ossification centers of the phalanges and metacarpal
of the thumb appear in the second to fourth fetal months, but
abnormalities of the skeleton of the thumb (e.g., triangular or
trapezoidal bones) may not be seen radiographically until
well into the first or second year of life. Secondary ossification
centers within the epiphyses of the thumb normally appear
between 13 months to 4 years of age.16 The delayed appear­
ance of both primary and secondary ossification centers in the
hypoplastic thumb is highly relevant to the diagnostic process
because their appearance is often delayed in proportion to the
degree of hypoplasia.
Basic science/disease process
Incidence
The true incidence of thumb hypoplasia is difficult to deter­
mine due to the large number of congenital malformations
within which a hypoplastic thumb is a component part.
All reported reviews are subject to study of the genetic com­
position of the patient population as well as any discrepancies
of nomenclature and sampling. Entin17,18 reported a 16%
  Access video content for this chapter online at expertconsult.com

593.e1
Historical perspective
Historical perspective
The history of thumb reconstruction mirrors the development
of hand surgery as a subspecialty. As such, advances in diag­
nosis, classification, and treatment of these conditions are
relatively new – having occurred in the past 6 decades.
Because many children with thumb anomalies have more
serious conditions, advances in anesthesia also had to take
place to make surgery safer and more predictable.
In terms of diagnosis and classification, Flatt stressed
function potential and designated the digits as “adequate”
or “inadequate”1,2; Bayne relied upon localized positions of
deficiencies3; and three generations of German authors
referred to the degree of skeletal hypoplasia.4–6 The system
proposed by Blauth recognizes the progressive degree of
hypoplasia from a slight size discrepancy, with all normal
structures present, to total aplasia of the thumb. In time, this
system has been amended by others,7,8 who subdivided type
III (severe hypoplasia) into two groups – those with an intact
carpometacarpal (CMC) joint (IIIA) and those without (IIIB)
– and is very important in terms of management. Recently,
Tonkin wrote a thorough summary of the grading systems,
clarifying the definitions of grades of thumb hypoplasia, and
proposing a modification of the Blauth classification.9
Progress in the treatment of thumb hypoplasia mirrored
advances in diagnosis and classification. Working indepen­
dently in Europe, Gosset10 and Hilgenfeldt11 developed the
procedure of digital transposition for post-traumatic thumb
losses. In the decades following World War II, Bunnell
described similar digital transpositions.12 Littler13 refined their
techniques and applied them to congenital differences. Fol­
lowing the thalidomide crisis in Europe, Buck-Gramcko14
amassed a large clinical experience and set present day stan­
dards for pollicization.

594
SECTION IV
CHAPTER 27 • Congenital hand III: Thumb hypoplasia
with thumb anomalies who underwent testing, six had a
positive test (7%). The authors noted that patients with thumb
hypoplasia and other associated conditions such as café-au-
lait spots and short stature appear to be at increased risk of
FA. Treatment of FA children with oxymetholone and predni­
sone therapy has a 70% response rate, and non-responders
can be treated with bone marrow transplantation.22 In 40
Table 27.1  ‘Thumb/radial hypoplasia/aplasia/dysplasia
associations’
Frequent in
Occasional in
Thumba/radialb hypoplasia/aplasia
Aase syndromea,b
Baller–Gerold syndromea,b
Facio-auriculo-vertebral spectruma
Fanconi syndromea,b
Holt–Oram syndromea,b
Levy–Hollister syndromea,b
Nager syndromea
Radial aplasia–thrombocytopenia
(TAR) Syndromea,b
Roberts–SC phocomelia syndromea,b
Rothmund–Thomson syndromea
Townes syndromea
VACTERL associationa,b
13q-syndromea
EEC syndrome
Cat-eye syndromeb
de Lange syndromea,b
Fetal aminopterin effectsa
Fetal: valproate effectsa
Fibrodysplasia ossificans
progressivea
MURCS associationa
Nager syndromeb
Seckel syndromeb
Trisomy 13 syndromeb
Trisomy 18 syndromeb
Metacarpal hypoplasia – first,c alld
CHILD syndromed
Coffin–Siris syndromed
Cohen syndromed
Diastrophic dysplasiac
Dyggve–Melchior–Clausen syndromec
Grebe syndromed
Oro-palato-digital syndrome, type IId
Partial trisomy 10q syndromec
Poland anomalyd
Ruvalcaba syndromed
Short rib–polydactyly, Majewski typed
Short rib–polydactyly, non-Majewski
typed
Tricho-rhino-phalangeal syndromed
Trisomy 9p syndromed
5p-syndromed
18q-syndromed
de Lange syndromec
Larsen syndromed
Robinow syndromed
Triploidy syndromec
Broad thumb
Apert syndrome
Carpenter syndrome
Pfeiffer syndrome
Rubinstein–Taybi syndrome
Saethre–Chotzen syndrome
Robinow syndrome
Trisomy 13 syndrome
a,b,c,dRefers to the hypoplasia/aplasia associations of the listed syndromes. For
example, Aase syndrome has both thumb and radial hypoplasia but Nager
syndrome has just thumb hypoplasia.
(Data from Jones KL. Smith’s Recognizable Patterns of Human Malformations,
5th edn. Philadelphia, PA: WB Saunders; 1997; and Rayan G, Upton J.
Congenital Hand Anomalies and Associated Syndromes. Berlin: Springer-Verlag;
2014.)
incidence of thumb hypoplasia in his Canadian patients,
while Flatt published an 11.2% incidence of thumb abnormali­
ties and a 3.6% incidence of thumb hypoplasia or aplasia from
his clinic in Iowa.2 We have seen a 37% incidence within our
entire registry, which includes many additional categories.19
The majority of the children treated surgically are those with
radial dysplasia – with and without a partial or complete
absence of the radius. We have also seen a high incidence in
syndromic patients, such as those with the Apert syndrome,
who are commonly referred to large children’s hospitals for
treatment of their multiple malformations. Other populations
include those with constriction ring syndrome (CRS), cleft
hands, and symbrachydactyly hands, all of whom may have
some degree of thumb hypoplasia.
Etiology
Because radial or preaxial longitudinal deficiencies occur in
many conditions with a wide variety of etiologies, the causes
for these malformations span the entire spectrum of genetic,
environmental, teratogenic, and other factors (Table 27.1).20
Therefore, consultation with a genetic specialist is strongly
recommended, and referral to standard genetic textbooks or
the Online Mendelian Inheritance in Man (OMIM) website
() is a must for any
pediatric hand surgeon.
Associated conditions
The many potential associations with thumb and radial hypo­
plasias and aplasia may involve any organ system within the
body. Most significant are those with cardiovascular, gastro­
intestinal, and genitourinary involvement. Associated hema­
tologic problems, specifically Fanconi anemia, can be detected
early but usually become clinically apparent later in child­
hood. The most common of these associated conditions is
outlined herein.
VACTERL
These children may have a wide spectrum of anomalies,
including: Vertebral malformations; Anal atresia or hypopla­
sias; Cardiovascular anomalies; all degrees of Tracheoesopha­
geal fistuli; Esophageal atresia; Renal malformations, and
Limb abnormalities – which in the upper extremity involve
all degrees of radial dysplasia. A patient does not need to
fulfill every category on this list to be considered VACTERL.
Fanconi anemia and other hematologic
abnormalities21
Children with Fanconi anemia (FA) develop different degrees
of pancytopenia, the most extreme of which can be life threat­
ening.22,23 Most of these children are small with growth restric­
tion. Although many other organ systems may be abnormal,
deficiencies of the thumb and, to a lesser extent, the entire
radial ray are the most common and are present at birth in
over half of these cases. Although in the past FA children were
rarely diagnosed early in life, this condition can be diagnosed
any time with a diepoxybutane (DEB) test.22,24 Recently, Webb,
et al.25 looked at the incidence of Fanconi anemia in children
with congenital thumb anomalies referred for DEB testing in
a tertiary care pediatric center, and found that of 81 patients

595
Diagnosis and patient presentation
five designated types of thumb hypoplasia–aplasia are shown
in Fig. 27.1. These anomalies are commonly associated with
radial (preaxial) dysplasia, and the majority of congenital
hand surgeons consider most types of thumb hypoplasia
with a normal radius as part of this spectrum. It is well
recognized that there are concomitant soft-tissue anomalies
that accompany the skeletal abnormalities. Since the cor­
relation of soft-tissue and skeletal deficiencies has been so
well defined, this refined system works very well for clinical
decision-making.
The classification system proposed by Blauth5 continues to
be the most commonly used. The modification proposed by
Manske8 subdivides the type III thumb into those with stable
carpometacarpal (CMC) joints and those with unstable CMC
joints. This subdivision has significant implications for treat­
ment, as the best reconstructive operation for the unstable
CMC joint is index finger pollicization.
Hypoplasia of the thumb is associated with many other
congenital differences, specifically central and transverse
deficiencies. Because the anatomical make-up of the thumb
does not always allow for easy categorization under the
current system, we have included five additional categories,19
which include the constriction ring syndrome, central defi­
ciencies, radial duplication, the five-fingered hand, and short
skeletal rays. In these conditions, the thumb ray usually has
characteristic deficiencies that would fall into the German
type II and III hypoplasia categories5,26 and the anatomical
abnormalities relevant to clinical decision-making will be
presented here.
Clinical presentation (types of hypoplasia)
In the past, routine radiographs were the sole tool used for
diagnosis of the hypoplastic thumb. However, this mode of
assessment did not reveal any detail about the normal and
abnormal soft-tissue structures of individual hands. There­
fore, surgeons today use a more complete analysis of intrinsic
muscles, webspace size, intrinsic muscles, extrinsic tendons,
joint stability, and function – all of which impact directly upon
treatment. It is difficult to adequately classify a hypoplastic
thumb in a newborn infant. The authors have found it best to
wait until the child is about 1 year of age, at which time
physical characteristics and functional use are the main deter­
minants of classification.
years, the senior author has treated four children who died
prematurely as a result of Fanconi anemia – children who
could have potentially benefited from life-saving bone marrow
transplant if the diagnosis was made early.
Clinical tips
Fanconi anemia
The low incidence of Fanconi anemia should be balanced
against the life-threatening consequences of a missed
diagnosis to guide testing in the current healthcare
environment. The DEB tests costs between $1000 and $1200.
The hematologists at our center have noted that all patients
with Fanconi anemia have high mean corpuscular volume
(MCV) on routine blood testing. Accordingly, one could
consider DEB testing only in those patients with thumb
hypoplasia who have high MCV and another clinical finding on
examination (as noted above). Additional data is needed to
lend credence to this consideration.
Fig. 27.1  Thumb hypoplasia. Molds of the right hand in six children with the five
classic types of thumb hypoplasia are displayed. Type III has been subclassified
into two categories: one with an intact carpometacarpal (CMC) joint (IIIA) and one
without an intact CMC joint (IIIB). The type IV is often called the pouce flottant or
floating thumb.
Holt–Oram syndrome
Two pediatricians, Dr. Holt in Philadelphia and Dr. Oram in
London, independently described the association of congeni­
tal heart disease and radial longitudinal defects of the upper
limb, and their names have subsequently been associated
with all degrees of congenital cardiovascular malformations
and radial dysplasia. Interestingly, there is no correlation
between the severity of the anatomic deficiency in one system
relative to the other. Common to the upper limbs are a stiff
hypoplastic thumb joined to a stiff index digit by a complete
simple syndactyly, radial deficiencies, and proximal radioul­
nar synostoses. Often, hypoplasia of the glenohumeral joint is
not diagnosed until adolescence when shoulder abduction is
diminished.
Thrombocytopenia absent radius syndrome (TAR)
This unique group of children may be born with normal
hematologic parameters, but they usually have a low platelet
count, which may decrease rapidly during the first year of life.
They are easily distinguished from children with other types
of radial dysplasia due to the presence of a thumb despite all
degrees of radial deficiencies. The thumb is hypoplastic, and
extrinsic flexion and extension vary tremendously. Thenar
intrinsic muscles are usually present and provide some palmar
abduction by age 2 years of age. The low platelet count com­
monly reaches normal levels by ages 4–5 years, and the clinical
results from centralization are among the best.
Diagnosis and patient presentation
Classification
The varying degrees of differences between hypoplastic
thumbs have been classified in a number of ways that have
few common characteristics. Nevertheless, a well-accepted
classification system has emerged that guides treatment. The

596
SECTION IV
CHAPTER 27 • Congenital hand III: Thumb hypoplasia
Clinical tips
Evaluating MP joint laxity
It is often quite difficult to differentiate between a normal and a
lax metacarpophalangeal joint in an infant with thumb
hypoplasia. Whereas absence of thenar musculature and a
diminutive webspace are usually obvious, the MP joint is quite
elastic and floppy in many normal infants. The authors have
found that it is best to wait until the child is older to fully
evaluate the MP joint. Functional observation of the older child
can be as valuable a tool as physical examination. An older
infant or younger toddler who can grasp a large object (such
as a flashlight) in one hand using the thumb likely has a stable
MP joint. Another who uses the thumb metacarpal head to
stabilize the object likely has too much laxity and will need
reconstruction.
A
Type I
Adductor
pollicis
muscle
Adductor
pollicis
muscle
Flexor pollicis
brevis muscle
Abductor pollicis
brevis muscle
Abductor pollicis
brevis muscle
Opponens
pollicis muscle
First dorsal
interosseous
muscle
Fig. 27.2  Type I thumb hypoplasia
– mild. (A) The skeletal ray is well
segmented and may be short. All intrinsic
muscles and extrinsic tendons are intact.
First webspace narrowing is minimal to
moderate. (B) Clinical appearance and (C)
radiograph of a child who did not require
any surgical correction. Although his
thenar muscles are weak, there were no
significant functional problems.
B
C
Type I: mild hypoplasia
In this most mild type of hypoplasia, the thumb is slender and
slightly shorter than a normally configured first ray (Fig. 27.2).
The phalanges and metacarpal can be slightly thinner than
usual, but the trapezium and scaphoid are present and the
distal radius and styloid process are not affected. The inter­
phalangeal (IP), metacarpophalangeal (MP), and CMC joints
are stable and exhibit normal passive and active motion.
While there may be a slight hypoplasia and weakness of the
abductor pollicis brevis (AbPB), opponens pollicis (OP), and
lateral head of the flexor pollicis brevis (FPB) muscles, all
intrinsic muscles are present.26 The joints, ligament and
capsules, tendons, nerves, and vascular structures are all
normal, and there may be minimal narrowing of the first
webspace.

597
Diagnosis and patient presentation
Type II: moderate hypoplasia
The metacarpal and phalanges are all present but small, and
the trapezium, trapezoid, scaphoid, and – to a lesser extent
– lunate may be hypoplastic. The first webspace is short with
the thumb adducted, the ulnar collateral ligament at the MP
joint lax, and median innervated thenar muscles underdevel­
oped or occasionally absent (Fig. 27.3).27 Normally, the flexor
pollicis brevis (FPB) and opponens pollicis (OP) are inner­
vated by the median nerve, but the FPB varies, reported to be
40% median, 48% ulnar, and 12% both median and ulnar.28
The ulnar innervated intrinsics, particularly the adductor
pollicis (AddP), pull the metacarpal into adduction and
narrow the first webspace, which, when explored surgically,
has tight fibrous bands between muscle groups. Type II
thumbs contain two neurovascular bundles, and the recurrent
motor branch of the median nerve is consistently found.
Many different muscle and tendon anomalies seen on the
radial side of the hand have been identified in conjunction
with the type II and IIIA thumbs. In fact, the clinical designa­
tion of a given thumb may vary greatly due to this large
spectrum of soft-tissue abnormalities. The absence of IP or MP
flexion or extension creases in a slender thumb is the best
clinical indicator of flexor and/or extensor abnormalities.
Within this designation, many variations of the long flexor to
the thumb (flexor pollicis longus; FPL) may be found. Both
A
Adductor
pollicis muscle
Type II
Adductor
pollicis
muscle
Flexor pollicis
brevis muscle
Abductor pollicis
brevis muscle
Abductor pollicis
brevis muscle
Opponens
pollicis muscle
First dorsal
interosseous
muscle
Fig. 27.3  Type II thumb hypoplasia – moderate. (A) There is minimal to moderate shortening of the skeletal ray. All bones are present and ligaments at the
metacarpophalangeal (MP) joint may be lax. The ulnar innervated intrinsic muscles, adductor pollicis and first dorsal interosseous (second metacarpal origin) are strong,
and the median innervated intrinsics are very weak. Anomalous anatomy is common. Adduction contractures from fibrous structures and MP joint instability accompany a
deficient first webspace. (B) Clinical appearance and radiograph of a child with a type II hypoplasia of the right hand. The thenar intrinsic muscles are hypoplastic, the first
webspace tight, and the thumb much narrower than normal. Key pinch was weak, and the patient could not hold heavy objects between the thumb and digits. In addition,
the ulnar collateral ligament was weak at the MP joint.
B

598
SECTION IV
CHAPTER 27 • Congenital hand III: Thumb hypoplasia
Median innervated intrinsic muscles are either severely
hypoplastic or absent entirely; however, if they are present,
they may actively flex the MP joint. The ulnar innervated
AddP pulls the metacarpal medially. The MP joint is lax on
both radial and ulnar sides and anatomically either collateral
ligament and the volar plate may be severely hypoplastic
or missing. The small thumb with a short webspace is
abducted at the MP joint due to the frequent pollex abductus
deformity. The radial origin of the first dorsal interosseous
from the thumb metacarpal is more severely affected than
that from the index metacarpal. In the forearm, radial head
is usually hypoplastic and commonly subluxed, occasionally
dislocated.
Abnormal anatomy is the rule. The many intrinsic and
extrinsic anatomical variations described within the type II
group may exist with greater degrees of hypoplasia. Usually,
the extrinsic flexor and extensor are present and weak, but in
some cases they may be missing.36,40,43 The flexor retinaculum
is poorly developed with either attenuation or absence of the
major pulleys. In some patients, the motor branch of the
median nerve is absent, and there may only be one neurovas­
cular bundle.31 The radial origin of the first dorsal interosseous
to the index finger is severely hypoplastic, and the first web­
space is severely restricted. Pollex abductus anomalies are
common and must be recognized and corrected if IP flexion
and/or extension is to be achieved.
Type IV: floating thumb
These thumbs (pouce flottant, French; pendeldaumen, German)
arise distally from the palm and usually lie along the radial
midaxial border (Fig. 27.7). They are attached only by a soft-
tissue pedicle, which has been described by Littler as “Nature’s
own neurovascular pedicle”, due to the presence of a digital
artery, two vena comitantes, and one or two nerves within the
skin bridge.48,49 There may be anomalous vascular or neural
rings, involving neurovascular structures15 that could affect
the outcome of a pollicization. There is no metacarpal, and
two small phalanges tend to be present within the soft-tissue
envelope, which contains a nail. It is important to note that a
diminutive nail represents the presence of a distal phalanx.
Intrinsic muscles do not insert onto these bones. A first dorsal
interosseous muscle (abductor indicis) may be detected by
abduction of the index finger. At the carpal level, the trape­
zium and less often the scaphoid are missing. The radial
styloid may be absent, but the distal end of the radius is
normal in most of these children.
the tendon and the muscle belly of the FPL may be abnormal,29
may have proximal duplications,30–34 and may have a more
radial distal insertion.31 In some patients, one can observe this
muscle originating from the index profundus tendon,31 the
transverse carpal ligament, or the fascia of the thenar intrinsics
and inserting into the flexor sheath30 and/or the extensor
mechanism.35 In other cases, this muscle may be absent
entirely.36–40 Some of these anomalies may represent abnormal
radial wrist extensors or short thumb abductors instead of
malformed or malpositioned terminal thumb flexors.41 Occa­
sionally, a small abnormal “musculus lumbricalis pollicis”
muscle may extend from the thumb origin across the first
webspace and attach to the flexor system of the index finger.42
We have seen this peculiar (atavistic) muscle extending across
the first webspace in children with the Freeman–Sheldon
syndrome and in complex thumb duplications at the metacar­
pal level.
The extrinsic extensors may have abnormal insertions,43,44
extend over the MP joint in a non-centralized position, and
reveal abnormal connections with the extrinsic flexor.33,35,42,45
These abnormal insertions of both flexor and extensors, com­
bined with their deviated course, conspire to make both
tendons act primarily as radial deviators and not primary
flexors or extensors. This deviation is further accentuated by
the lax ulnar collateral ligament at the MP joint, resulting in
more deviation. Tupper45 has called this “pollex abductus”
and noted that when these muscles contract, there is no IP
flexion or extension, only abduction or radial deviation of the
thumb. Many anatomical variations of this structure exist, but
the functional result is the same (Fig. 27.4). A recent paper by
Graham et al.33 has summarized the large list of muscle and
tendon abnormalities that often originate in the forearm.
Although type II thumbs may present with these intratendi­
nous connections, the abducted posture and wide degree of
muscle and tendon anomalies are primarily seen with type
IIIA thumbs (see Fig. 27.4). When followed proximally to the
wrist and forearm level, many of these tendons have abnormal
origins and long muscle bellies that extend well beyond the
wrist into the metacarpal region.
Type III: severe hypoplasia
In these cases, the degree of skeletal shortening and narrow­
ing is much more pronounced, particularly at the metacarpal
level (Figs. 27.5 & 27.6). The hand and wrist may be radi­
ally deviated due to hypoplastic/aplastic carpal bones. The
trapezium is usually very small, and frequently the scaphoid
is absent. The distal radius is smaller in size and the styloid
process absent, giving the radius a blunted appearance.46
The extreme amount of anatomic variation within this
group prompted Manske and colleagues to subdivide this
group into type IIIA with a full-length metacarpal and an
intact CMC joint and type IIIB with a tapered first meta­
carpal and no CMC joint.8 Buck-Gramcko has included an
additional variation called type IIIC thumb, which possesses
only the metacarpal.47 There are no tendons or muscles in
this variant, and the skin bridge is much wider than that
seen in type IV. In the B and C variants, a fibrous band
may connect the hypoplastic metacarpal to a cartilaginous
nubbin that represents either a trapezium or metacarpal
base. Often, a small abductor pollicis tendon attaches to this
remnant.
Clinical tips
Aesthetic augmentation
The pouce flottant in type IV or the ablated thumb in type IIIB
thumbs can be used for additional bulk in the thenar area. The
technique is easy and improves appearance in these deficient
hands. The part is stripped of skin, nail, and skeletal elements
and rendered a vascularized adipofascial flap based on its
original blood supply. It is then transposed into the thenar area
at the conclusion of the procedure for additional bulk.49

599
Diagnosis and patient presentation
Fig. 27.4  Pollex abductus. (A) In severe type II and many type III thumbs, there may be very little, if any, interphalangeal joint flexion and there may be a radial deviation of
the thumb at the metacarpophalangeal (MP) joint. This is due to the abduction force created by the combined action of the extrinsic flexor and extensor tendons joined by
intertendinous connections, the “pollex abductus”. (B–E) Within types II and III thumb hypoplasias (and proximal thumb polydactylies), a very wide spectrum of
intratendinous connections may vary between a wide, loose, almost areolar band (top) to a complete coalition the flexor and extensor into a single tendon. With excursion
from either the flexor or extensor side, the resultant movement in all these thumbs is abduction of the MP joint.
A
Abduction
B
D
C
E

600
SECTION IV
CHAPTER 27 • Congenital hand III: Thumb hypoplasia
Fig. 27.5  Type IIIA thumb hypoplasia – severe. (A) These thumbs exhibit more severe skeletal hypoplasia, including the carpal bones. Median nerve innervated thumb
intrinsic muscles are severely hypoplastic or absent, and the ulnar-innervated muscles are present but weak. Extrinsic tendons are abnormal, the “pollex abductus” deformity
is frequent, the first webspace is small, and the metacarpophalangeal (MP) joint is unstable (more on the ulnar than the radial sides). The carpometacarpal (CMC) joint and
thumb metacarpal are intact in IIIA thumbs. (B–E) The clinical appearance and radiograph show a short slender metacarpal, an intact CMC joint, severe hypoplasia of the
thenar eminence, and a lax MP joint. The absent interphalangeal flexion crease is indicative of a deficient or absent flexor pollicis longus.
A
Type IIIA
Adductor
pollicis
muscle
Adductor
pollicis muscle
First dorsal
interosseous
muscle
B
C
D
E
Type V: aplasia
The thumb is completely absent in this category (Fig. 27.8). In
half of our patients50 and half those reported by Flatt,51 there
is an associated deficiency of the radius. When the radius is
normal, the index digit is normal and has strong abduction at
the MP joint due to the presence of a strong first dorsal inter­
osseous muscle (e.g., abductor indicis muscle). Many of
these children with a normal radius will demonstrate “auto-
pollicization”.50 The pulp of the index finger widens and the
digit pronates and sits in a more abducted position resulting
in a widening of the intermetacarpal space and attenuation of
the intermetacarpal ligament. At best, this posture is a poor
substitute for normal key pinch. In the case of a deficient
radius, the index ray is stiffer, shorter, and often joined by a
simple syndactyly to the long digit. There is a direct correla­
tion between the degree of radial hypoplasia and the index
finger deficiencies; the index ray is never normal when there
are significant associated radial deficiencies. In these hands,
the degree of stiffness decreases from the radial to the ulnar
digits and the fifth finger is always the best on the hand.
Type VI: central deficiencies – cleft hand and
symbrachydactyly thumb
Cleft hand (typical)
Cleft hand is characterized by hypoplasia or aplasia of the
central ray(s) of the hand thus forming a “V” or funnel-shaped
cleft (Fig. 27.9
). All degrees of simple syndactyly of the first

601
Diagnosis and patient presentation
Fig. 27.6  Type IIIB thumb hypoplasia – severe. (A) The median-innervated thenar intrinsic muscles are absent entirely. There is severe hypoplasia of the adductor pollicis
muscle, flexor pollicis brevis – lateral head, and the ulnar origin of the first dorsal interosseous. The carpometacarpal joint articulation of the proximal metacarpal is absent.
The metacarpophalangeal joint is very lax or absent on both radial and ulnar sides. Flexor and extensor extrinsic tendons are severely hypoplastic or absent. (B,D) Clinical
appearance and (C) radiograph shows a 4-year-old patient with a well formed but functionless floppy thumb. There is no skeletal stability or extrinsic flexion or extension.
Very small flexor or extensor tendons may be present and can result in some movement.
A
Type IIIB
Adductor
pollicis
muscle
Adductor
pollicis muscle
First dorsal
interosseous
muscle
B
C
D
web are seen, resulting in moderate to severe deficiencies of
the first webspace. In addition, all degrees of hypoplasia,
extending to aplasia of the central two rays, may exist.7,8 The
ulnar two digits in the ring and fifth positions are commonly
webbed with simple syndactylies. The thumb in the cleft hand
anomaly is usually slightly small with all components of the
osteoarticular skeleton present. A Blauth type II thumb clas­
sification would be appropriate for the strict constructionist.26
The wrist and forearm bones are normal, and the median
innervated thenar intrinsics are present. The major deficiency
of the thumb in this form of hypoplasia is that the ulnar
innervated intrinsic muscles are severely hypoplastic or
absent. In particular, the ulnar innervated adductor pollicis is
usually severely hypoplastic or absent, and the first dorsal
interosseous is moderately hypoplastic and contracted. The
presence or absence of the third metacarpal is often an excel­
lent indicator of the status of the AddP muscle. Finally, the
extrinsic flexor and extensor musculotendinous units to the
thumb tend to be unaffected. Fig. 27.9 appears online only.
In another variation of typical cleft hand, thumb polydac­
tylies at all levels may be observed. The more distal type I and
II polydactylies52 are often associated with the absence of
index phalanges that have an intact metacarpal. Super digits
and transversely oriented tubular bones at the distal metacar­
pal level with complete absence of the index (and long) digits
are often seen in this variation.53 With more proximal type III,

601.e1
Diagnosis and patient presentation
A
VI A Typical cleft hand thumb
Adductor
pollicis muscle
Abductor pollicis
brevis muscle
Abductor pollicis
brevis muscle
Opponens
pollicis muscle
First dorsal
interosseous
muscle
Fig. 27.9  Thumb in typical cleft hand. (A) Three layers of median innervated intrinsic muscles are present in most typical cleft hands. Commonly, the index ray is joined to
the thumb by a simple syndactyly. All degrees of absence of the long rays may present. The first dorsal interosseous is present and tight, and the degree of adductor
pollicis hypoplasia is proportional to the amount of the third metacarpal present. A very small adductor pollicis is illustrated here. (B) A sampling of molds shows the wide
variation in the size and depth of the central clefting. The thumbs are smaller than normal, and the longer thumbs with flexion contractures are triphalangeal.
B

602
SECTION IV
CHAPTER 27 • Congenital hand III: Thumb hypoplasia
extrinsic musculotendinous units. Frequently, this digit has a
radial clinodactyly and a completely unstable MP joint, and
the entire hand is hypoplastic. Radius and ulna are present
and of equal length but may be small in comparison to the
opposite limb.
Type VII: constriction ring syndrome
Constriction ring syndrome (amniotic band sequence, Street­
er’s dysplasia, fenestrated syndactyly, acrosyndactyly) is a
condition that can affect one or all limbs and less commonly
the face. As defined by Patterson,56 limb involvement
can result in any of the following deformities: (1) simple
constriction rings, which may be partial or circumferential;
(2) constriction rings with distal deformity, with or without
concomitant lymphedema; (3) acrosyndactyly (distal fusion,
fenestrated syndactyly); or (5) amputation(s) (Fig. 27.11
).
Fig. 27.11 appears online only.
Hypoplasia of the thumb is seen in this condition when
there is a deficiency in the length of the thumb, which may
have a transverse failure of formation at any level. Occasion­
ally, the existing skeletal and soft-tissue components of the
first ray may be hypoplastic. The hallmark of the amniotic
band sequence is that the anatomy proximal to the level of
amputation or level of congenital amputation is normal.
Superficial or deep rings around the thumb can be associated
with hypoplasia or lymphedema of the distal segment of the
digit that contains hypoplastic nail remnants and slender,
truncated phalanges. Acrosyndactyly (acros: peak, Greek)
usually involves the central three rays of the hand but can also
involve the thumb and fifth digit. Thumb amputation may
occur at any level. The most practical way to classify these
losses is at one of three levels: (1) distal to IP joint; (2) proximal
phalanx, and (3) metacarpal (see Fig. 27.11). Motion of the IP
joint is usually severely affected – even with amputations or
deep constriction rings distal to it.
IV and V polydactylies, the central (third) ray is often severely
hypoplastic or absent.54,55 Triphalangeal rays may also be
encountered with the proximal duplications at the metacarpal
level.
Symbrachydactyly thumb
Most refer to these atypical cleft hands as symbrachydactyly
(Fig. 27.10
). This form of deficiency is always unilateral,
with varying degrees of hypoplasia of the central three rays
of the hand. Nubbins with minute nail complexes may be
present on the distal border of the palm, representing the
index, long, and ring fingers, but commonly these central
three digits are completely absent with varying degrees of
hypoplasia of the central three metacarpals. Fig. 27.10 appears
online only.
All degrees of variation exist, and no two hands are identi­
cal. The thumb in this condition is invariably smaller with
severe hypoplasia or aplasia of the phalangeal components.
Occasionally, a metacarpal and distal phalanx are present
with a flail thumb at the MP joint level. With an intact third
metacarpal, a functional adductor pollicis muscle is often
present. Most of these thumbs have very weak adduction
power. Usually, the median innervated thenar intrinsic
muscles are intact and range from small to normal in size.
The thumb CMC joint is well segmented and mobile, and
the IP joint of the thumb may exhibit decreased passive
and active motion due to weak extrinsic flexor and exten­
sors. Upon exploration, the FPL tendon often courses to a
hypoplastic or absent muscle belly in the distal forearm. In
the severely hypoplastic thumb, there is marked limitation
of MP and CMC motion, an absent IP flexion crease, and
only a rudimentary FPL tendon. The anomalies seen with the
extrinsic flexors and extensors are similar to those described
for the types II and IIIA hypoplastic thumbs. The fifth ray
is usually the best in the hand with intact intrinsic and
Fig. 27.7  Type IV thumb hypoplasia – floating thumb. (A) The hypoplastic thumb is attached to the hand only by a soft-tissue bridge, which contains neurovascular
structures and rarely hypoplastic tendons and fascia. There is no skeletal connection. (B,C) The attached thumb is small with diminutive phalanges and a nail. There is no
active flexion or extension. The radial deviation of the wrist and hand is due to hypoplasia of the trapezium, scaphoid and lunate.
A
Type IV
B
C

602.e1
Diagnosis and patient presentation
A
VI B Symbrachydactyly thumb
Abductor pollicis brevis
Abductor digiti quinti
Opponens digiti quinti
Fig. 27.10  Symbrachydactyly thumb (atypical cleft). (A) The border thumb and fifth rays are the most complete in the hand. Thenar and hypothenar muscles are present
and often small. Central digits are represented by hypoplastic nubbins. There are all degrees of metacarpal hypoplasia within the central three rays of the hand. Extrinsic
flexors and extensors are present but abnormal. (B) A very wide range of variation is present in these hands.
B

A
B
Fig. 27.11  Constriction ring syndrome thumbs. (A) The thumb in these hands may present with a shallow or deep constriction ring or an amputation at any level along the
skeletal ray. The phalanges at the level of loss are characteristically narrow and taper to the distal stump. (B) The intrinsic muscles are all present up to the level of the
amputation. The proximal anatomy in this condition is normal. (C) The thumb is absent on the left and shows increasing length in these molds. No two hands are identical.
There is great variation in the depth and location of constriction rings along the digits.
C

603
Diagnosis and patient presentation
Fig. 27.8  Type V thumb hypoplasia/aplasia. (A–C) With complete aplasia, no thumb structures are present. In approximately half of these patients, the radius is normal.
The trapezium, trapezoid, and scaphoid are often hypoplastic and a strong first dorsal interosseous (abductor indicis) pulls the index digit in abduction and in as much
pronation as the intermetacarpal ligament will allow. (D–F) Index digits, which are not abducted, are often stiff at the interphalangeal joints and are commonly associated
with some degree of radial hypoplasia or aplasia. The amount of stiffness decreases from radial to ulnar digits. Accordingly, the ring and small fingers are always the most
functional components of these hands.
A
Type V
First dorsal
interosseous muscle
(Abductor indicis)
B
C
D
E
F
Type VIII: five-fingered hand
In this type of hypoplasia, the thumb is smaller in width and
longer in length and has the characteristics of a finger. As the
radial border digit, it lies in the same plane as the ulnar four
digits and is non-opposable. It is usually the same length as
the adjacent index finger. The digit is slender and may be
joined to the index finger in an incomplete simple syndactyly.
A severe deficiency or nonexistent first web is often present,
and some type of transverse metacarpal ligament is also
present. The skeletal anatomy is similar to that of the index
ray: a metacarpal with a distal growth center and three pha­
langes with proximal growth centers. The scaphoid is usually
absent or hypoplastic. The thenar musculature (AbPB, FPB,
OP muscles) are also absent as is the AddP. Instead, the usual
digital intrinsics are present – namely, a lumbrical, palmar,
and dorsal interosseous (Fig. 27.12
). The extrinsic flexors
and extensors mimic those of the normal fingers. Because the
radial digit lies in the same plane as the other fingers in
the hand, manipulation of objects is usually performed by

604
SECTION IV
CHAPTER 27 • Congenital hand III: Thumb hypoplasia
broad. Incidentally, many feel that the abnormal proximal
phalanx and broad distal phalanx are variations of a polydac­
tyly. Musculotendinous anomalies are associated with poor
joint function but are not as common as those with type IIIA
thumbs. Deficiencies of the first web are most common, occur­
ring along a spectrum of mild adduction contracture to
complex syndactyly involving the first two rays. Fig. 27.13
appears online only.
The whole spectrum of patients with metabolic bone dis­
eases, skeletal dysplasias, benign skeletal tumors, and many
syndromes may include thumb hypoplasia. In general, very
little surgical correction is required for these youngsters. The
need for surgical improvement is determined by very critical
observation of these children at play.20
Patient selection
General considerations
The child with thumb hypoplasia may present many unique
problems with both pinch (precision, pulp, key) and grasp
(precision, span, power), despite his/her ability to adapt
remarkably to the functional deficiency.57 The ideal prerequi­
sites for reconstruction of a functional thumb include 19,58:
1. A mobile, stable CMC joint with an intact metacarpal
2. A scar-free first webspace of adequate width and depth
lined with full-thickness skin
3. Mobility in at least two of its three joints (CMC, MP, IP)
4. MP joint stability, particularly of the ulnar collateral
ligament
5. Adequate motors for strong MP or IP flexion and
extension
6. Capacity to be placed in a palmar abducted (i.e.,
opposition) position for pinch and grasp maneuvers.
All six of these components should be considered in any
detailed analysis of the thumb.
Timing
As researchers and clinicians struggle with the possibilities
of fetal surgery, many surgeons wonder if they should wait
rather than performing reconstructive procedures of the
congenitally different hand as soon as possible (Fig. 27.14).
Early reconstruction of the hypoplastic or absent thumb is
certainly attractive in an effort to allow the infant to adapt
more rapidly with optimal cortical representation. This ideal
needs to be tempered with the knowledge that a congenital
hand difference is, in itself, not a life-threatening condition
(but may be associated with one), and the surgeon can use
time to allow the affected part to grow, to observe develop­
ment, and to assess the functional needs. The construction of
the thumb with a stable osteoarticular column of adequate
length, mobile joints, growth potential, scar-free first web, and
gliding muscle tendon units is not easily accomplished in very
small hands – despite refined microvascular instruments and
skills.
However, the arguments that are forwarded by the propo­
nents of the early surgery persist. The most powerful argu­
ments include anatomic, cognitive, and psychological factors.
Anatomically, the release of tethered musculotendinous units
utilizing lateral scissoring between the first two digits – or
between the second and third if a first web syndactyly is
present. Left untreated, those patients without a first web
syndactyly tend to attenuate the transverse metacarpal liga­
ment and “auto-pollicize” into an abducted and slightly
pronated posture. Fig. 27.12 appears online only.
We have seen variants of this condition in which hypoplas­
tic thenar muscles are present with a metacarpal that has a
proximal physis. These thumbs are triphalangeal and also
contain a lumbrical muscle that originates from the flexor
digitorum profundus (FDP) tendon.
Type IX: radial polydactyly
Despite the level of arborization, each partner thumb is hypo­
plastic to varying degrees, with the radial duplicate usually
being the most severely affected. Rarely are Wassel type II,
III, and IV partner thumbs of equal side and conformity.
The complexity of the deformity and, therefore, the surgical
correction increases as the level of the duplication progresses
proximally. Associated triphalangia of the ulnar partner
further complicates any surgical reconstruction. Specific
abnormalities in each thumb are seen in the nail plate, the
osteoarticular column, and both the intrinsic and extrinsic
musculotendinous units. The nail plate of each partner
is always more narrow than that of the unaffected thumb,
and the entire skeletal ray is hypoplastic in all polydactylies
proximal to the MP joint.
Musculotendinous abnormalities are common with the
extrinsic extensor almost universally shared. Indeed, nearly
half of the patients presented in papers on pollex abductus
involve duplicate thumbs.42,45 Deviation of the partners toward
each other indicates abnormal insertions of the extrinsic
tendons into the distal phalanges, and connections between
the extrinsic flexors and extensors are not unusual. These
tendinous interconnections will limit function and cause
digital angulations. The first web is usually unaffected in
polydactylies involving the distal phalanx, but as the level of
arborization lies more proximally, the first webspace becomes
increasingly deficient and tight.
Type X: syndromic short skeletal thumb ray
Deficiencies of the osteoarticular column of the thumb may
result in a short, hypoplastic thumb (Fig. 27.13
). Bony
abnormalities can occur as isolated bone (brachymetacarpia,
brachyphalangia), all bones in combination, or as part of a
generalized syndrome, such as the acrocephalosyndactyly
(e.g., Apert, Pfeiffer, Carpenter, etc.) syndromes or the
Rubinstein–Taybi syndrome. Joint function is usually impaired
on either side of the abnormal bone(s). In patients with
anomalies of a single bone, brachymetacarpia, or brachypha­
langia, the remaining components of the thumb tend to be
unaffected, and in patients with generalized syndromes, other
abnormalities of the thumb components are common. In the
acrocephalosyndactyly (ACS) syndromes, delta phalanges are
common. They usually involve the proximal phalanx with a
longitudinal epiphyseal bracket on the radial side. This abnor­
mal growth plate checks longitudinal growth on the radial
side and results in radial clinodactyly of the thumb (“hitch
hiker’s thumb”) – which becomes more severe over time. The
metacarpal is usually short and the distal phalanx is short and