Phẫu Thuật Gân Bàn Tay (Tendon Surgery of the Hand)

338
Section 3:  Secondary Flexor Tendon Surgery
SUMMARY
The use of vascularized tendon grafts nourished by ulnar
artery through mesotendon, with all gliding surfaces
intact, provides new methods to reduce adhesions and
has the added merit of being a one-stage procedure.
These types of vascularized tendons or tendon and flap
transfers are indicated in secondary reconstruction and
can be expected to offer effective options for tendon
reconstruction. Transfer of vascularized flexor tendon
system from the toes or homotransplants of the digital
flexor tendon are additional sources of tendon grafts.
tourniquet is applied to the upper arm just before aorta
clamping. While the heart, liver, and kidney are removed
by other surgical teams, the author’s team harvested the
flexor tendon from the forearm. Above procedures may
take more than 2 hours.
The ulnar artery and its branches nourishing the
tendon are identified in the forearm. The FDS of the ring
finger is dissected at the tendon–muscle junction. All
the branches of the ulnar artery nourishing the tendon
as well as adjacent mesotendon are carefully preserved.
The superficial palmar arcade is then clamped and tran­
sected distally to the third common palmar digital artery,
preserving the two collateral arteries inside the donor.
The functional unit composed of the FDS and FDP
tendons and all the pulleys is then separated from the
phalanges through a medial approach. Dissection is per­
formed under the periosteum over the phalanges, but
the flexor sheath is not opened. The radial side of the
ring finger is similarly dissected. Upon completion of
above dissections, the only remaining link between the
structure to be transplanted and the donor’s hand is the
ulnar artery. The tourniquet is then released. The super­
ficial veins of the forearm are used for venous drainage.
The ulnar artery is ligated proximal to its branches sup­
plying the harvested skin. The transplant is placed in a
sterile plastic container filled with serum at 4°C.
The donor tendon is brought to the recipient patient
to repair tendon defects in the digits. The proximal parts
of the grafted FDS and FDP tendons are passed under
the superficial palmar arch of the recipient hand and is
sutured to the distal end of the recipient tendons with
a Pulvertaft method. The ulnar artery of the donor is
connected to that of the recipient with an end-to-side
anastomosis. The superficial veins of the donor are also
anastomosed with recipient anterior forearm veins.
Total ischemia time is 3 hours.
In these patients, the swelling abated little by little
after surgery, and good functional results were obtained
4 months later. One patient had a passive flexion of 80°
in the PIP joint without extension defect, and passive
flexion of 55° in the DIP joint with an extension deficit
of 35° (Figure 31[A]-16). The average total active
flexion almost equaled the range of passive motion. This
finger is now very functional and fully adapted. The
merit of the procedures is to reconstruct all the pulleys,
to keep the digital sheath intact, and to avoid adhesion
formation.
Figure 31(A)-16  Free vascularized flexor tendon
allografting. A, Loss of flexion of the ring finger before surgery.
B, Harvested allograft. C, Finger flexion 1 year postoperatively.
A
B
C
References
1. Potenza AD: Critical evaluation of flexor-tendon healing and
adhesion formation within artificial digital sheaths, J Bone
Joint Surg (Am) 45:1217–1233, 1963.
2. Lundborg G, Holm S, Myrhage R: The role of the synovial
fluid and tendon sheath for flexor tendon nutrition. An exper­
imental tracer study on diffusional pathways in dogs, Scand
J Plast Reconstr Surg 14:99–107, 1980.
3. Littler JW: Free tendon grafts in secondary flexor tendon
repair, Am J Surg 74;315–321, 1947.
4. Hunter JM: Tendon salvage and the active tendon implant: A
perspective, Hand Clin 1:181–186, 1985.
5. Paneva-Holevitch E: Résultats du traitement des lésions mul­
tiples des tendons fléchisseurs des doigts par greffe effectuée
en deux temps, Rev Chir Orthop Repar 58:481–487, 1972.

339
Chapter 31A:  Tendon Vascularity and Gliding, Island and Free Vascularized Transfers
flexor tendon salvage surgery, Plast Reconstr Surg 92:888–903,
1993.
14. Guimberteau JC, Goin JL, Panconi B, et al: The reverse ulnar
artery forearm island flap in hand surgery; 54 cases, Plast
Reconstr Surg 81:925–932, 1988.
15. Guimberteau JC, Panconi B: Recalcitrant non-union of the
scaphoid treated with a vascularized bone graft based on the
ulnar artery, J Bone Joint Surg (Am) 72:88–97, 1990.
16. Boyles JH: Flexor-tendon grafts in the fingers and thumb: an
evaluation of end results, J Bone Joint Surg (Am) 32:489–499,
1950.
17. Strickland JW: Results of flexor tendon surgery in zone II,
Hand Clin 1:167–179, 1985.
18. Cavadas PC, Mir X: Single-stage reconstruction of the flexor
mechanism of the fingers with a free vascularized tendon flap:
Case report, J Reconstr Microsurg 22:37–40, 2006.
19. Peacock EE Jr: Homologous composite tissue grafts of the
digital flexor mechanism in human beings, Transplant Bull
7:418–421, 1960.
20. Guimberteau JC, Baudet J, Panconi B, et al: Human allotrans­
plant of a digital flexion system vascularized on the ulnar
pedicle: A preliminary report and 1-year follow-up of two
cases, Plast Reconstr Surg 89:1135–1147, 1992.
6. Zbrodowski A, Gajisin S, Grodecki J: The anatomy of the
digitopalmar arches, J Bone Joint Surg (Br) 63:108–113,
1981.
7. Verdan CE: Half a century of flexor-tendon surgery. Current
status and changing philosophies, J Bone Joint Surg (Am)
54:472–491, 1972.
8. Smith JW: Peripheral nerve surgery—retrospective and con­
temporary techniques, Clin Plast Surg 13:249–254, 1986.
9. Schatzker J, Branemark PI: Intravital observations on the
microvascular anatomy and microcirculation of the tendon,
Acta Orthop Scand (Suppl) 126:1–23, 1969.
10. Guimberteau JC: New Ideas in Hand Surgery; Island Vascular­
ized Flexor Tendon Transfers, the Sliding System. France, 2002,
Aquitaine Domaine Forestier, p 210.
11. Guimberteau JC, Sentucq-Rigall J, Panconi B, et al: Introduc­
tion to the knowledge of subcutaneous sliding system in
humans, Ann Chir Plast Esthet 50:19–34, 2005.
12. Guimberteau JC, Bakhach J: Subcutaneous tissue function:
the multimicrovacuolar absorbing sliding system in hand and
plastic surgery. In Siemonov MZ, editor: Tissue Surgery, Berlin,
2006, Springer, pp 41–54.
13. Guimberteau JC, Panconi B, Boileau R: Mesovascularized
island flexor tendon: new concepts and techniques for

340
Serge Rouzaud
B
Physiotherapy After Vascularized
Tendon Transfers
PHYSIOTHERAPY AFTER SURGERY
Timing
Postoperative physiotherapy starts early after surgery, so
as to limit or at least modulate tendon adhesions due
to scar healing. Physiotherapy must be careful and effi­
cient. This requires perfect knowledge of the kind of
surgery, the methods of tendon repair, and the pulleys
that may have been rebuilt. The physiotherapist must
have a thorough knowledge of physiopathology of the
tendon so as to ensure the quality of the work.2 The
physiotherapist should ensure sufficient therapy to
improve the results but avoid being too aggressive,
which could cause disruption or diastasis at tendon
junctions that hampers the result.
Three Phases of Physiotherapy After Surgery
The surgical technique consists of the transfer of a vas­
cularized sliding unit to favor intrinsic healing. The
proximal and distal tendon junctions are situated in
zones 1, 3, or 4, which are deemed “safe” and may
shorten the period of putting the tendon in rest position
and favor active flexion exercise. The protocol that we
have made for vascularized tendon transfer comprises
three stages: days 0 to 21, days 21 to 45, and after day
45, governed by the periods of tendon healing. Days 0
to 21 represent the most important stage. In this stage,
the therapy determines the final result by limiting adhe­
sions arising from extrinsic healing and favoring intrin­
sic healing.
Splinting and Joint Positions
Within the first 72 hours after surgery, a modified Klein­
ert splint is applied (Figure 31[B]-1). The wrist is set at
the neutral position, metacarpophalangeal (MCP) joints
are set in 60° flexion, and the interphalangeal (IP)
joints are set at flexion between 0° and 10°.3 The trac­
tion is anchored in distal part of the nail distally and
runs under a pulley, which allows a flexion of three
digital joints (MCP and proximal and distal [PIP and
DIP] joints). The friction forces against the pulley are
limited by a nylon thread tethered to a rubber band
below the pulley. The tension of the rubber band must
OUTLINE
As is the case with all physiotherapy following repair
of the flexor tendon, the return of satisfactory active
motion amplitudes, in flexion as well as in extension,
requires a specific physiotherapy program. The therapy
must be modified in different postoperative periods
with emphasis of different exercises. This chapter
describes specific day-by-day therapy regimens that are
used in the cases of vascularised tendon transfer. Such
therapy must respect not only the recipient digit and
its vascular anastomoses, but also the donor digit, so
that function of the donor and recipient digits is
restored as much as possible.
Physiotherapists are confronted with new surgical
methods of flexor tendon reconstruction with vascular­
ized tendon transfers.1 This technique provides a last
resort solution to salvage a nonfunctional finger. At this
stage, the patient has had a long history of time-
consuming treatment, which has often not only kept the
patient from professional activities but also greatly
reduced the ability to perform day-to-day tasks. This last
resort solution is proposed at the end of a long treat­
ment, often after amputation of the finger has been
evoked; therefore, it can represent hope for the patient.
Nevertheless, the risk of lassitude and diminished will­
ingness to participate in the treatment is great. The
medical team should therefore encourage and support
the patient in this ultimate stage of the treatment.
PREOPERATIVE PHYSIOTHERAPY
Physiotherapy starts before surgery for the patients with
complex hand trauma. The therapy is usually applied to
a finger with serious limitation in passive extension and
flexion. The presurgery phase is important to improve
the quality of local tissues and restore passive joint
motion as much as possible. The improvement in the
quality of tissues and joint suppleness obtained in this
phase will reduce “surgical aggression” and create a
proper local status, which would favor improvement of
hand motion and therefore outcomes of the surgery.

341
Chapter 31B:  Physiotherapy After Vascularized Tendon Transfers
Methods of Physiotherapy
In the first phase we aim to reach following goals at day
21: (1) passive flexion of the MCP, PIP, and DIP joints
back to normal, (2) normal extension of the IP joints
or at least limited to a 20° flexion, and (3) active flexion
from 0° to 60° on the PIP joint and from 0° to 20° on
the DIP joint.
In this phase, we perform daily physiotherapy: (1)
Prevention of edema. Edema is a factor favoring tendon
adhesions and articular ligament retractions. Measures
to prevent edema must start as soon as possible after
surgery, such as elevation of the upper limb and mobi­
lization of adjacent digits.5,6 (2) Passive mobilization.
Passive mobilization keeps the joints mobile, and these
exercises also allow differential FDS and FDP tendon
motion in case the FDP is rebuilt with an intact FDS
tendon. It is important to maintain the MCP joints in
extension while the IP joints are flexed (Figure 31[B]-4).
(3) Active mobilization. Surgeons and physiotherapists
should decide together whether to undertake active
motion according to strength and quality of tendon
junctions. The Pulvertaft method of proximal junction
and distal reinsertion by pull-out technique appear to
be reliable in strength. Protected active flexion was
advocated by Rouvillois7 and Bellemère.8 The place-and-
hold is exercised and the amplitude of active digital
flexion is gradually increased. Place-and-hold exercises
are less aggressive and are often easily achieved by the
patient. This exercise may avoid resistance during move­
ment. When a tendon is transferred to a finger with an
intact FDS, differential motion of two tendons needs to
be practiced (Figure 31[B]-5). Between day 8 and day
15, the tendon is weak and the exercises are fewer.
be as weak as possible, yet still able to bring the finger
into full flexion (see Figure 31[B]-1). The wrist at
neutral position allows the proximal tendon junction
site to move and glide, favoring forming gliding surfaces
between the tendon and surrounding tissues.
Once the splint is applied, the patient carries out 10
active extensions an hour, with a passive return to
flexion by tension of the rubber band, and 10 active
flexions of the wrist with return to extension as far as
the splint allows, so as to favor gliding of the different
tissues and to disrupt adhesions (Figure 31[B]-2 and
31[B]-3). The active extension should not be forcefully
against the splint.4 The patient relaxes during active
extension to reduce resistance. Edema and dressings are
reduced to lower resistance to extension.
Figure 31(B)-1  Modified Kleinert splint with a palmar
pulley.
0°
60°
Figure 31(B)-2  Active extension against the rubber band.
Figure 31(B)-3  Passive flexion with the rubber band force.

342
Section 3:  Secondary Flexor Tendon Surgery
This exercise does not stimulate FDP tendon gliding on
the FDS, but the FDS tendon is not present in most
instances of this type of tendon reconstruction. The dif­
ferential motion should be exercised every day.
It is noteworthy that development of flexion contrac­
ture of the joint after these surgical reconstructions,
especially at the DIP joint, is very likely under rubber
band traction. Lack of extension of the finger up to
about 60° may be observed very early, which is difficult
to correct if not taken care of. When a flexion contrac­
ture of more than 20° is present in the PIP and/or the
DIP joints, we modify the splint as early as day 15 after
surgery. The rubber band is temporarily withdrawn and
a Velcro strap is made setting the finger in an intrinsic
plus position. The strap is gradually tightened by the
patient to increase joint extension. The rubber band is
re-positioned every hour to achieve a series of 10 active
extensions with passive return to flexion. Between day
21 and day 45, the splint is removed during the day time
and the joint is gradually allowed to actively move, but
the splint is kept at night. If active flexion of the finger
can be easily achieved by day 21, we apply the splint
only for 8 more days, but the pull-out suture is kept for
another 10 days.
During the therapy period, passive motion is per­
formed every day. Ample passive motion amplitudes are
always emphasized. The finger extension is also sought,
and usually increases at week 5 or 6 after surgery. Intrin­
sic muscle weakness or contracture may develop and
electric stimulation helps prevent such problems.
After removal of the splinting, exercise of active finger
flexion should be increased. The place-and-hold exercise
is gradually given way and active movement, with no
resistance, is encouraged. During active movement, the
rebuilt pulleys are to be protected. Elastoplast strapping
can be used to protect the pulley with no risk to the
vascularization. Protection to the pulleys is required
until the end of 2 months after surgery. The active flexion
of the donor finger is exercised. Electrical stimulation to
the FDP tendon of the donor finger help build the
strength of digital flexion, we do so as early as week 5.
After day 45, active exercises are increased and the
patient is urged to start all daily activities. To favor the
recruitment of neuromuscular activity, electrical stimu­
lation to the FDP muscle to which the grafted tendon
is sutured is added if there are difficulties in active
flexion of the repaired finger. The site of electrical stimu­
lation must be as specific as possible, entailing adequate
setting of skin electrodes. Exercises that enhance func­
tion of wrist and hand as a whole also begin at this time.
Late Therapy of Extension Deficits
Development of extension deficits is not uncommon,
despite all the measures used in the earlier periods to
prevent finger flexion contractures. In the late stage, it is
often necessary to apply a dynamic extension splint
Reconstructed pulleys must be protected during
active finger flexion by positioning the fingers of the
physiotherapist correctly over these pulleys to reduce
the tension.9 The protection with Elastoplast rings is
risky because of precarious skin healing. Their tourni­
quet effect may damage vascular supply of the flap.
The donor finger, usually the ring finger, must be
included into active flexion exercises. Removal of the
FDS may cause adhesions of the intact FDP tendon of
this finger, which should be avoided. If extension deficit
of the donor finger is present, a Velcro strap is installed
to place the finger in intrinsic plus position to correct
the extension deficit.
The tendon motion by means of tenodesis effect is a
useful method.10 Active wrist extension favors passive
flexion of the fingers and vice versa. The patient should
be relaxed to reach maximum efficiency during exercise.
Figure 31(B)-5  Place-and-hold IP joint flexion with MP
joint extension.
Figure 31(B)-4  Passive PIP joint flexion of the finger with
the transferred tendon.

343
Chapter 31B:  Physiotherapy After Vascularized Tendon Transfers
use of the hand should be encouraged in the intervals
when the splint is removed, so as to render function and
use of the hand, which has already been insufficiently
used for several months or even several years.
In some cases, above measures may not effectively
correct the deficit in extension of the PIP and/or DIP
joints. We then use a series of plaster casts between
physiotherapy sessions. Tubular splint may also be
applied. This technique was originally developed for the
treatment of irreducible flexion contracture accompany­
ing untreated PIP joint sprains. It is extended to the
treatment of irreducible flexion contracture, regardless
of the cause.
Additional Methods
During physiotherapy, classic techniques of circulatory
massages and scar softening must be an integral part
of our work to fight edema and pain, which favor pre­
venting adhesions and joint stiffness. Deep pressure
massage is an excellent adjuvant for the treatment of
skin adhesions and scarring. Silicone gels are advised
when scars are hypertrophic.
It should also be emphasized that during the process
of physiotherapy, we, physiotherapist and patient, must
be patient, and active and regular physiotherapy must
not be limited to the sessions directed by the
therapist.
(Figure 31[B]-6). Such a splint should be adapted to
the affected joints (usually the IP joints). The splint is
mainly worn at night, as well as during day periods of
two hours in the morning and two hours in the after­
noon if the flexion contracture is difficult to correct. The
splint is kept till obtaining a good-quality extension.
Frequently, this splint should be worn for 4 to 6 months.
However, the splint must not be worn continuously
during the daytime (which some patients are inclined
to do because the splint is better tolerated when they
move than at night when they are at rest). Instead, active
Figure 31(B)-6  The strap is gradually tightened by the
patient as the tissues allow more extension.
References
1. Guimberteau JC, Panconi B, Boileau R: Mesovascularized
island flexor tendon: new concepts and techniques for flexor
tendon salvage surgery, Plast Reconstr Surg 92:888–903,
1993.
2. Caffinière JY, Simmons BP: Physiologie de la flexion des
doigts. In Tubiana R, editor: Traité de Chirurgie de la Main.
Tome 1, Paris, 1980, Masson, pp 339–411.
3. Kleinert HE: Réparations primitives des tendons fléchisseurs.
In Tubiana R, editor: Traité de Chirurgie de la Main. Tome 3,
Paris, 1986, Masson, pp 198–205.
4. Van Alphen JC, Oepkes CT, Bos KE: Activity of the extrinsic
finger flexors during mobilization in the Kleinert splint,
J Hand Surg (Am) 21:77–84, 1996.
5. Thomas D, Moutet F, Guinard D, et al: Mobilisation posto­
pératoire immédiate des tendons fléchisseurs, Ann Kinésithér
27:338–347, 2000.
6. Aoki M, Manske PR, Pruitt DL, et al: Work of flexion after
tendon repair with various suture methods, J Hand Surg (Br)
20:310–313, 1995.
7. Tubiana R: Considerations anatomo-pathologiques et
biologiques. In Tubiana R, editor: Traité de Chirurgie de la
Main. Tome 3, Paris, 1986, Masson, pp 49–61.
8. Rouvillois A, Sifre G, Hu W, et al: Mobilisation en flexion
active protégée associée à la technique de Kleinert, Ann
Kinésithér 19:123–138, 1992.
9. Bellemère P, Chaise F, Friol JP, et al: Résultats de la mobilisa­
tion active précoce après réparation premiers des tendons
fléchisseurs, La Main 3:221–234, 1998.
10. Zhao C, Amadio PC, Momose T, et al: Effect of synergistic
wrist motion on adhesion formation after repair of partial
flexor digitorum profondus tendon lacerations in a canine
model, J Bone Joint Surg (Am) 80:78–84, 2002.

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345
SECTION
4
EXTENSOR TENDON REPAIR
AND RECONSTRUCTION

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347
CHAPTER
32 
EXTENSOR TENDON INJURIES—
PRIMARY MANAGEMENT
Brandon E. Earp, MD, and Philip E. Blazar, MD
proximal to a juncturae can be masked on examination
by the ability to extend the injured digit at the MCP
joint through an intact juncturae to an adjacent tendon.
(3) Because of the superficial location of the extensors
partial and complete injuries can and do occur with
seemingly minor lacerations. (4) Injuries may be ini­
tially compensated for by the duplications and intercon­
nections of the extensor mechanism but a clinically
significant deformity can develop with time. (5) A high
percentage of these injuries have associated bone, skin,
or joint injury.1
A major component of the care of tendon injuries is
rehabilitation with controlled early motion. While
exceptions exist, the vast majority of flexor tendon inju­
ries are currently treated with early motion. In the exten­
sor system, the biomechanical characteristics of repair
do not as routinely allow for the same degree of early
mobilization. In general, the biomechanical strength of
utilized repairs is dependent on the zone of injury.
Hence the most important factors in determining the
treatment of extensor tendon injuries include the ana­
tomical zone, the chronicity of the injury, and any
pathology of the adjacent tissues (principally skin,
bone, and joints).
The remainder of this chapter will discuss extensor
tendon injuries, repair, and rehabilitation based on ana­
tomical zone.
ZONE 1—DIP JOINT
The relatively complex anatomy of the extensor hood
becomes much simpler distally as the terminal tendon
is the only structure that extends the distal joint. In
addition, the terminal tendon is a surprisingly delicate
structure when handled surgically, particularly after
trauma. Disruption of the terminal tendon at this level
is commonly referred to as a “mallet” finger because
of the characteristic flexion deformity (Figure 32-1).
Closed injuries are the most routinely seen variant and
occur from multiple mechanisms ranging from injury
in sports with a ball striking the tip of the digit to
“trivial” injuries such as tucking in bed sheets. The ulnar
digits are more commonly affected and males with this
injury tend to have it a younger age than women. Injury
OUTLINE
Acute extensor tendon injuries to the hand and wrist
have typically received less attention than their flexor
counterparts. The anatomy of the extensors is para­
doxically more complex and the management of inju­
ries is more varied and corresponds to the anatomical
zone of injury. In this chapter, the anatomy, identifica­
tion, and management of injury based on anatomical
zone are reviewed. Surgical and nonsurgical treatment
of these injuries is discussed, including the indica­
tions. The role of early mobilization after injury and
repair is described.
The extensor tendon system of the wrist, hand, and
fingers is surprisingly complex. The six extensor com­
partments of the wrist and the intrinsic muscles of the
hand comprise 23 musculotendinous units. Open and
closed injuries to these structures are more common
than injuries to the flexor structures and range from very
subtle, seemingly minor traumas to overt complex inju­
ries with failure and/or loss of multiple tissue types.
Failure to diagnose and treat these injuries, including
those in the superficially subtle categories, can lead to
significant loss of motion and function.
The zones of injury have been assigned beginning
distally with odd numbered zones located over the
respective distal interphalangeal (DIP), proximal inter­
phalangeal (PIP), metacarpophalangeal (MCP), and
wrist joints, while the even numbered zones are located
over the underlying intervening osseous structures (see
Chapter 1, Figure 1-7). The detailed anatomy of these
tendons is discussed in Chapter 1.
A few general anatomical points are critical to be
aware of when evaluating patients with potential inju­
ries to the extensor mechanism. (1) Variations in exten­
sor anatomy are common, such as extensor digiti minimi
(EDM) duplication, absence of extensor digitorum com­
munis (EDC) to the small finger. (2) The juncturae
tendinum (see Chapter 1, Figure 1-7) connect the EDC
tendons of the ulnar four digits and are more common
and more substantial (tendon like) on the ulnar part
of the hand. An injury to the extensor mechanism

348
Section 4:  Extensor Tendon Repair and Reconstruction
recommended to asses for fracture and joint sub­
luxation. Management of the injury is based on the
category of injury (i.e., closed versus open, acute versus
chronic, etc.).
Closed mallet injuries without a fracture are managed
by observation, immobilization, or surgery. Nonsurgical
treatment is most commonly used in the treatment of
closed mallet injuries and is used for the vast majority,
including those with fractures that involve one third of
the articular surface or less. Joint subluxation is typically
not seen until approximately 50% of the articular surface
is involved. Controversy exists over the type of immobi­
lization, length of immobilization, and the need to
include the PIP joint. The principle of immobilization
is to maintain the DIP joint in extension to approximate
the injured structures and allow for healing. Constant
immobilization is maintained for 6 to 8 weeks but care
must be exercised as dorsal skin compromise occurs,
particularly if the DIP joint is positioned in hyperexten­
sion. A recent randomized trial suggests that digit-based
cast treatment leads to a lower rate of skin problems and
improved patient compliance.5 Some authors advocate
restarting the period of immobilization if the DIP
becomes flexed at any point during the treatment cycle.
The same protocol is typically recommended for patients
who present subacutely up to at least 8 weeks from
injury.
Some residual deformity (extensor lag) in the inter­
mediate and long term is common but rarely function­
ally limiting.6,7 Furthermore, the apparent extensor lag
may improve over an extended period of time of up to
1 year.8
Mallet fractures are also typically managed with a
similar protocol of closed treatment. The most accepted
indication for surgery is joint subluxation; however,
some advocate surgical treatment for large fragments in
the absence of subluxation. Techniques include open
reduction and internal fixation with small screws,
K-wires, or a pull-out suture/wire. Pinning of the DIP
joint in extension is commonly considered, particularly
in the situation where the fixation is not rigid. A closed
technique of extension block pinning, where the DIP
joint is brought into full flexion and a K-wire is intro­
duced into the middle phalanx and then the joint is
extended. The previously inserted K-wire serves to block
extension of the fractured fragment while allowing
extension of the remainder of the distal phalanx, reduc­
ing the fracture. The two distal phalangeal fragments are
then pinned to each other and/or the DIP joint is pinned
in a neutral position. The K-wires are left in about 6
weeks, until clinical union.9
Open mallet injuries are commonly associated with
loss of skin and/or tendon substance as well as a trau­
matic arthrotomy requiring débridement. Even if there
is no loss of tissue, the soft tissue injury can be expected
to be more severe than with a closed injury. While many
is thought to occur from any activity that results in
forced flexion of the tip of a digit. Variations include
closed, open with or without tissue loss, and mallet
fractures (Figure 32-2); it is not infrequent for these
injuries to present late after trauma. Mallet fractures
involving large portions of the articular surface can lead
to joint subluxation.2 Injuries older than 4 weeks have
been classified as “chronic.”3
The resulting deformity ranges from a small extensor
lag to a lag equivalent to full passive DIP flexion. In
some patients the deformity seems to progress over a
few hours or days, suggesting that partial injuries may
become worse with further trauma or with routine use.
Mallet finger injuries may lead to a swan-neck deformity
(flexion of the DIP and PIP hyperextension) through
overpull of the extensors at the PIP joint. This is more
common in individuals with PIP joint volar plate laxity
and illustrates the concept that a tendon imbalance at
one interphalangeal (IP) joint may lead to an opposite
deformity in the adjacent IP joint.4
Diagnosis and categorization of a mallet injury
are based on the posture of the digit and typically
straightforward. Radiographs of the injured digit are
Figure 32-1  Clinical presentation of mallet injury with
flexion deformity at the DIP joint.
Figure 32-2  Radiograph of bony mallet injury with distal
phalangeal intra-articular fracture.

349
Chapter 32:  Extensor Tendon Injuries—Primary Management
open extensor injuries are treated with suture repair of
the tendon, the nature of the tendon at this level makes
a biomechanically strong repair challenging. Many sur­
geons choose to add K-wire fixation as an internal splint
or to incorporate the skin in a tenodermodesis repair.
With a tenodermodesis repair a suture or sutures are
placed through the dorsal skin and tendon and the
repair includes both skin and tendon with the same
suture. The tenodermodesis stitch is left in for 6 weeks
in contrast to standard skin sutures so a less reactive
nonabsorbable material such as polypropylene suture is
used.10
In open injuries with tendon or skin loss, wound
management needs to be considered. Local advance­
ment flaps can make up for small defects and skin grafts
can also be helpful in select situations (Figure 32-3).
There are also indications for heterodigital flaps for loss
of larger amounts of skin. Free tendon grafts are also
occasionally needed to reconstruct the extensor mecha­
nism. While these more severe injuries are likely to
include more loss of motion at the DIP joint due to their
more severe trauma, it is important to maintain PIP
joint mobility so the overall impact on the total digital
motion is minimized.
Rehabilitation for all mallet injuries focuses on main­
taining DIP joint extension without even momentary
exception for the first 6 weeks in the vast majority of
cases, regardless of treatment. During that time PIP and
MCP joints and adjacent digit mobilization as well as
techniques to prevent skin complications are encour­
aged. If a splint is used, the skin is inspected daily; the
thumb and countertops or other external aids are used
to maintain the DIP joint in extension when the ortho­
sis is removed. Cast treatment obviates the need for skin
inspection except at the intervals of cast change. After
the period of absolute immobilization most protocols
typically require an additional period of approximately
the same length of night-time extension splinting.
Figure 32-3  A, Open mallet injury with soft tissue loss including skin and tendon. Note the transarticular K-wire. B, Local
advancement flap coverage of the defect.
A
B
ZONE 2—MIDDLE PHALANX
In contrast to zone 1 injuries, zone 2 injuries typically
occur from a laceration. Injuries at this anatomical level
are more likely to be partial with some intact tendon
and therefore some active extension. Despite the differ­
ence of only a few millimeters distance anatomically
from zone 1, these injuries are seen much less frequently.
In the scenario where only one lateral band is lacerated
(50% of the tendon or more is intact), the injury can be
treated with a short course of immobilization. Injuries
with an apparent extensor lag or loss of DIP joint exten­
sion strength should be treated with a longer period of
immobilization or with primary repair. Primary repair
is the preferred treatment for complete lacerations of the
extensor in this area (Figure 32-4). As these injuries
are less common there are no studies that specifically
compare the surgical techniques for repair at this level.
The options used range from technically simple sutures
(figure-of-eight or horizontal mattress) to more complex
such as the Silfverskiöld or an interlocking horizontal
mattress. Tenodermodesis has also been used in this
zone. Many authors chose to use a supplemental K-wire
across the DIP joint with the joint in extension to protect
the repair, particularly if there is loss of skin or tendon
substance.
Immobilization and rehabilitation are largely similar
to the more common zone 1 injuries. Six weeks of
immobilization of the DIP joint in extension with
mobilization of the PIP joint is maintained. Typically
this is in a splint or cast. Active flexion is permitted at
6 weeks but part time splinting at night is continued for
an additional 4 to 6 weeks.
ZONE 3—PIP JOINT
Zone 3 injuries occur in both open and closed manners.
However, closed injuries are frequently underappre­
ciated by patients and medical professionals. The

350
Section 4:  Extensor Tendon Repair and Reconstruction
they also occur at the PIP joint so vigilance is necessary.
In the absence of purulence or overt signs of infection,
surgical repair of the central slip is indicated. For inju­
ries without adequate distal tendon for direct repair,
suture anchor repairs are described. Biomechanically
suture anchor repair appears similar to suture repairs.12
Acute closed isolated central slip injuries are managed
nonoperatively. Extension splinting or casting of the PIP
joint is prescribed with the PIP joint in full extension
and the DIP “free” or capable of full flexion. Immobili­
zation is maintained for 6 weeks and is followed by a
period of night-time splinting in extension typically of
an additional 6 weeks. Active and passive DIP joint
flexion is performed throughout the treatment to mobi­
lize the lateral bands dorsally or at least prevent them
from subluxating volarly. The goal of treatment is to
prevent the secondary deformity (volar subluxation of
the lateral bands and DIP joint hyperextension) from
developing. For closed injuries with displaced avulsion
fractures and/or PIP joint subluxation/dislocation, open
treatment is indicated. Reconstruction of the central slip
insertion into the dorsal base of the middle phalanx is
performed. Depending on the fragment size and quality,
constructs using screws, K-wires, suture anchors or
tension band may be used. Joint instability may require
pinning the PIP joint in extension.
Subacute presentations are a frequent problem. This
occurs as the injuries are commonly underappreciated
and because attenuation of the central slip and the
resultant boutonniere deformity can develop over
weeks. In this situation, the goal of treatment is to
prevent development or worsening of the deformity.
Splinting of the PIP joint in extension while leaving the
DIP joint free to move is therefore indicated when an
injury to the central slip is suspected. Failure of initial
management of a central slip injury with development
of a boutonniere deformity is a controversial area. Many
authors will consider splinting in the subacute period
but surgical reconstruction is indicated in select cases
where nonsurgical treatment fails. Favored reconstruc­
tive techniques are more complex than reattaching the
retracted central tendon such as mobilization of a com­
ponent of the lateral band or a tendon graft such as a
slip of flexor digitorum superficialis (FDS) left attached
to the base of the middle phalanx. Boutonniere recon­
struction is discussed in more detail in Chapter 36.
Rehabilitation after central slip injury has tradition­
ally included immobilization of the PIP joint for 6
weeks with concomitant DIP joint motion. Loss of PIP
joint flexion has been a concern, particularly for open
injuries and some authors have advocated for earlier
range of motion (ROM). Pratt and colleagues13 described
a postoperative protocol that included 3 weeks of
immobilization followed by 3 weeks of protected
motion with a dynamic extension splint. No patient in
her series had an extension deficit over 15°.
functional morbidity of the resultant boutonniere
deformity is more limiting than the deformity of a
neglected mallet finger in most cases. Therefore, vigi­
lance is necessary to prevent the sequelae of this type of
injury. With closed injuries, patients present with swell­
ing at the PIP joint, decreased PIP joint extension
strength against resistance and a subtle PIP joint exten­
sion lag. The Elson test is the physical examination
maneuver that is felt to be the most specific for an early
closed central slip injury.11 The test is performed with
the PIP joint flexed 90° and the patient extends the IP
joints against resistance. A positive test shows increased
DIP extension than the contralateral or adjacent DIP
joint.
With an acute presentation, treatment depends on
whether the injury is open or closed. For open injuries,
an arthrotomy and irrigation and débridement of the
joint are indicated (see Figure 32-4). These injuries
occur from a variety of mechanisms and while human
mouth injuries are more common at the MCP joint,
Figure 32-4  A, Complete zone 2 tendon injury of the
middle finger in a patient who sustained a laceration on
glass to the dorsum of two fingers. B, Zone 3 injury with
open PIP joint of the index finger in the same patient.
A
B

351
Chapter 32:  Extensor Tendon Injuries—Primary Management
When tendon repair in this area is performed, proxi­
mal tendon retraction is rarely an issue, as the intact
sagittal bands and juncturae tendinea prevent signifi­
cant migration. Common suture techniques include the
modified Kessler, modified Bunnell, mattress, and
figure-of-eight. Care should be taken to avoid excessive
shortening of the tendon during repair, which can lead
to loss of flexion. Rehabilitation protocols are varied in
this region17,18 and include immobilization for 3 to 4
weeks with the wrist extended 45° and the MCP joints
in approximately 15° to 20° of flexion, followed by
mobilization.19-21 Alternate rehabilitation with a pro­
tected early motion protocol such as immediate con­
trolled active motion (ICAM) has been shown to be
effective, especially in long and ring fingers, which allow
for the best support of the digital “yoke.”22-26
Open sagittal band injuries should be repaired to
prevent subluxation of the extensor tendon away from
the side of injury. Displacement of the extensor tendon
from its central location may be associated with an
extensor lag or, in extreme cases, the inability to extend
across the MCP joint from a maximally flexed position.
Intrinsic contracture can result if left untreated. Closed
sagittal band injuries are frequently associated with
inflammatory systemic conditions, or related to blunt
trauma. Rupture of the sagittal fibers most often occurs
on the radial side of the middle finger, with ulnar dis­
placement of the extensor. Management of acute closed
sagittal band injuries includes immobilization in exten­
sion for 4 weeks, followed by a range of motion proto­
col.27,28 If closed treatment is unsuccessful, surgical
management includes repair of the torn sagittal band if
the tissues permit. A variant of this injury is the “boxer’s
knuckle,” which occurs via a direct blow to the extensor
mechanism over the MCP joint, leading to injury of
both the extensor mechanism and underlying joint
capsule.29 Reconstruction using a juncture or a slip of
ZONE 4—PROXIMAL PHALANX
Zone 4 injuries are similar to zone 2 in many ways,
although in zone 4 the anatomy is more complex. A
majority of the injuries seen at this level are open and
partial lacerations are the norm. Examination of a
patient with an injury at this level includes evaluation
for an extensor lag at the PIP joint or weakness of active
extension. In the absence of an extensor lag with the
ability to extend against resistance nonsurgical treat­
ment is recommended. This includes PIP joint exten­
sion splinting and early protected motion. Many injuries
in this zone occur in the setting of an open fracture.
Treatment of an associated skeletal injury may influence
the choice of closed versus open treatment and the tech­
nique of rehabilitation. The “dorsal combined injuries”
involving an unstable open fracture and a tendon lac­
eration are a distinct pattern of injury. Rigid internal
fixation of the fracture is typically advocated with repair
of the extensor tendon. Larger defects of the extensor
mechanism can be bridged with tendon graft. Great
care is taken during either repair or graft reconstruction
to ensure proper length balance of the central band
and lateral band, as imbalance in the length would
induce loss of finger extension. Extensor adherence over
the proximal phalanx may occur, which can lead to
decreased digital flexion, with possible need for later
tenolysis and joint release.
Patients with an extensor lag and/or lack of extension
against resistance have an indication for exploration
and likely repair. Once again a variety of tendon repair
techniques are used. Frequently repair is followed by 4
to 5 weeks of immobilization, with subsequent therapy.
Recent biomechanical data have shown that repairs
using the Becker and interlocking horizontal mattress
techniques are stronger than some more traditional
techniques.14,15 This has led some authors to advocate
beginning range of motion at 3 weeks postrepair.16
ZONE 5—MCP JOINT
Injuries to the extensor mechanism in zone 5 occur over
the MCP joint, and are frequently open injuries. A high
prevalence of these open injuries occur due to human
teeth; it is critical to identify patients with these “fight
bites” and aggressively treat them with operative irriga­
tion and débridement of the MCP joint as well as repair
of the tendon, if indicated (Figure 32-5). Due to the
common positioning of the digits in flexion when the
injury occurs, and the positioning of the digits in exten­
sion during the examination of the wound in the clini­
cal setting, an injury that extends to the joint may be
missed, as the affected portion of the tendon is now
much more proximally located. A high index of sus­
picion is appropriate when evaluating open injuries
in this zone. Bite wounds here should be irrigated,
débrided, and left open.
Figure 32-5  Open zone 5 “fight bite” injury involving the
tendon and joint.

352
Section 4:  Extensor Tendon Repair and Reconstruction
the tendon repair is located in the area of the extensor
retinaculum, a small section can be resected or a length­
ening of the retinaculum can be performed to prevent
bowstringing. The wrist is typically immobilized in 40°
extension, with the MCP joints held in neutral to slight
flexion for 3 to 4 weeks. Early motion of the IP joints
of the fingers is typically possible without undue stress
on the repairs.
The most common closed tendon injury at the wrist
is an extensor pollicis longus (EPL) rupture. Most fre­
quently occurring after closed treatment of a minimally
or nondisplaced distal radius fracture, the etiology is
thought to be secondary to ischemia in that region of
the tendon. The tendon ends are typically frayed, pre­
cluding end-to-end repair, thus reconstruction with
extensor indicis proprius (EIP) transfer or an interposi­
tion tendon graft are typically performed.35
Lacerations over the forearm may to injury of both
tendons and nerves. Nerve repairs should be performed
at the time of tendon repair. With multiple tendon inju­
ries, repair of all of the divided structures is recom­
mended (Figure 32-7). If the injury precludes direct
repair of all structures, repair to allow independent wrist
and thumb extension is the most important, and com­
bined extension of the digits is desired. Injuries at the
musculotendinous junction are challenging due to poor
strength of the repair in the muscle. Often a tendinous
portion can be found extending within the muscle belly
to a quite proximal extent and can be incorporated for
increased repair strength. Rehabilitation is similar to
zone 7 but may need to be modified based on the
mechanical strength of the repair in zone 8.
Zone 9 injuries are those in more proximal forearm
and result from sharp lacerations. Muscle, tendon, and/
or nerves, especially the posterior interosseous nerve
(PIN), are often simultaneously injured. Any nerve
the extensor tendon routed around a lateral band or the
radial collateral ligament is used for patients requiring
reinforcement of the native tissues. Chronic radial sagit­
tal band injuries may require release of the ulnar sagittal
band and centralization of the extensor.
ZONE 6—DORSUM OF THE HAND
Zone 6 injuries over the dorsum of the hand are less
common, but are often associated with significant
trauma, including fractures and major soft tissue inju­
ries. The extensor in this zone is more oval or circular
in cross section and more amenable to core suture repair
with 3-0 or 4-0 nonabsorbable suture (similar to those
for flexor tendon injuries). Early dynamic splinting
or ICAM protocols are often appropriate for these
patients; however, they may also be treated with immo­
bilization for 4 weeks after surgical repair, followed by
a standard mobilization. Complex injuries may neces­
sitate extended rehabilitation due to other affected
tissue structures such as bone or skin. Patients with
complex injuries may benefit from acute tendon recon­
struction performed in combination with free tissue
transfer for soft tissue coverage.30 Extensor adherence
to surrounding structures may lead to either extensor
lag or poor flexion from resultant joint contractures.
Uninjured digits in the hand can be similarly affected
from lack of mobilization with joint contractures and
tendon adhesions. Evans and Burkhalter31 describe early
motion protocols for injuries at this level involving
dynamic extension splints. They report full extension in
over 90% of their patients and no tendon ruptures.
Newport and colleagues have analyzed several studies
that compare static immobilization to early controlled
movement for uncomplicated injuries in zones 5 to 8
and found that 54 to 95% good or excellent results
were obtained with immobilization versus at least
90% good or excellent results for the early controlled
motion.32 Five millimeters of tendon excursion is suffi­
cient to prevent adherence of the repaired extensor,
which is correlated with range of motion at the various
joints.33,34
ZONES 7, 8, AND 9—WRIST, DISTAL, AND
PROXIMAL FOREARM
Zone 7 and more proximal extensor injuries are less
common. Appropriate identification of the proximal
ends of the transected extensor tendons in these areas
can be difficult. Knowledge of local anatomy including
the compartments, location of the muscle bellies, and
caliber of the tendons aids with identification (Figure
32-6). The proximal ends may also be retracted due
to muscle contraction, which may require extending
the proximal dissection. The distal ends are rather easy
to identify, as a gentle tug on the tendon stump will
elicit the expected distal movement. The tendons are
repaired using a strong nonabsorbable core suture. If
Figure 32-6  Open zone 7 injury with multiple tendons and
nerve transections.

353
Chapter 32:  Extensor Tendon Injuries—Primary Management
SUMMARY
Extensor tendon injuries are one of the common inju­
ries in the hand. Careful attention to the anatomical
details of the zone of injury and complicated mechani­
cal balance of the extensor system will determine
whether surgical or nonsurgical treatment is indicated.
As each component of extensor tendon over the fingers
tolerate little loss of tendon substances, in repairing the
extensor tendon, care should be taken to ensure minimal
shortening of the tendon substance to maintain intri­
cate mechanical balance of the extensor apparatus.
Though strength of repair is not as important as for
flexor tendons, a mechanically reliable repair method
should be considered. Extensor tendons injured at the
distal parts of the fingers, such as over the DIP or PIP
joint areas may develop joint deformities easily, leading
to chronic mallet finger or boutonniere deformities.
Correct splinting or surgical intervention at acute stage
is important to prevent development of these deformi­
ties. In many surgical cases, postoperative early motion
protocols help restore digital range of motion and
return patients to occupational and daily activities more
rapidly. Adhesions may develop, especially over the
fingers or at the extensor retinaculum, which may
require secondary tenolysis.
injuries should be identified and repaired at the surgery.
The muscle bellies are repaired, frequently with a figure-
of-eight suture. Fascia can be used to augment the
muscle repair. Above elbow immobilization is applied
when the injured muscles originate from the humeral
epicondyles.
Figure 32-7  Forearm laceration involving multiple tendon
injuries in zones 7 and 8.
References
1. Newport ML, Blair WF, Steyers CM Jr: Long-term results of
extensor tendon repair, J Hand Surg (Am) 15:961–966, 1990.
2. Kalainov DM, Hoepfner PE, Hartigan BJ, et al: Nonsurgical
treatment of closed mallet finger fractures, J Hand Surg (Am)
30:580–586, 2005.
3. Garberman SF, Diao E, Peimer CA: Mallet finger: results of
early versus delayed closed treatment, J Hand Surg (Am)
19:850–852, 1994.
4. Kaplan EB: Anatomy, injuries, and treatment of the extensor
apparatus of the hand and digits, Clin Orthop Relat Res 13:24–
40, 1959.
5. Tocco S: Effectiveness of cast immobilization in closed mallet
finger injury: A prospective randomized comparison with
thermoplastic splinting, J Hand Ther 20:362–363, 2007.
6. Bendre AA, Hartigan BJ, Kalainov DM: Mallet finger, J Am
Acad Orthop Surg 13:336–344, 2005.
7. Okafor B, Mbubaeqbu C, Munshi I, et al: Mallet deformity
of the finger: five-year follow-up of conservative treatment,
J Bone Joint Surg (Am) 79:544–547, 1997.
8. Pike J, Mulpuri K, Metzger M, et al: Blinded, prospective,
randomized clinical trial comparing volar, dorsal, and custom
thermoplastic splinting in treatment of acute mallet finger,
J Hand Surg (Am) 35:580–588, 2010.
9. Hofmeister EP, Mazurek MT, Shin AY, et al: Extension block
pinning for large mallet fractures, J Hand Surg (Am) 28:453–
459, 2003.
10. Kardestuncer T, Bae DS, Waters PM: The results of tenoder­
modesis for severe chronic mallet finger deformity in chil­
dren, J Pediatr Orthop 28:81–85, 2008.
11. Rubin J, Bozentka DJ, Bora FW: Diagnosis of closed central
slip injuries. A cadaveric analysis of non-invasive tests, J Hand
Surg (Br) 21:614–616, 1996.
12. Cluett J, Milne AD, Yang D, et al: Repair of central slip avul­
sions using Mitek Micro Arc bone anchors, J Hand Surg (Br)
24:679–682, 1999.
13. Pratt AL, Burr N, Grobbelaar AO: A prospective review of
open central slip laceration repair and rehabilitation, J Hand
Surg (Br) 27:530–534, 2002.
14. Lee SK, Dubey A, Kim BH, et al: A biomechanical study of
extensor tendon repair methods: introduction to the running-
interlocking horizontal mattress extensor tendon repair tech­
nique, J Hand Surg (Am) 35:19–23, 2010.
15. Woo SH, Tsai TM, Kleinert HE, et al: A biomechanical com­
parison of four extensor tendon repair techniques in Zone IV,
Plast Reconstr Surg 115:1674–1681, 2005.
16. Zubovic A, Egan C, O’Sullivan M: Augmented (Massachusetts
General Hospital) Becker technique combined with static
splinting in extensor tendons repairs zones III to VI: func­
tional outcome at three months, Tech Hand Up Extrem Surg
12:7–11, 2008.
17. Chester DL, Beale S, Beveridge L, et al: A prospective, con­
trolled, randomized trial comparing early active extension
with passive extension using a dynamic splint in the rehabili­
tation of repaired extensor tendons, J Hand Surg (Br) 27:283–
288, 2002.
18. Crosby CA, Wehbe MA: Early protected motion after extensor
tendon repair, J Hand Surg (Am) 24:1061–1070, 1999.
19. Newport ML: Extensor tendon injuries in the hand, J Am Acad
Orthop Surg 5:59–66, 1997.
20. Newport ML: Zone I-V extensor tendon repair, Tech Hand Up
Extrem Surg 2:50–55, 1998.
21. Rayan GM, Murray D: Classification and treatment of
closed sagittal band injuries, J Hand Surg (Am) 19:590–594,
1994.

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22. Howell, JW, Merritt WH, Robinson SJ: Immediate controlled
active motion following zone 4-7 extensor tendon repair,
J Hand Ther 18:182–190, 2005.
23. Ip WY, Chow SP: Results of dynamic splintage following
extensor tendon repair, J Hand Surg (Br) 22:283–287, 1997.
24. Khandwala AR, Webb J, Harris SB, et al: A comparison of
dynamic extension splinting and controlled active mobiliza­
tion of complete divisions of extensor tendons in zones 5 and
6, J Hand Surg (Br) 25:140–146, 2000.
25. Matzon JL, Bozentka DJ: Extensor tendon injuries, J Hand
Surg (Am) 35:854–861, 2010.
26. Mowlavi A, Burns M, Brown RE: Dynamic versus static splint­
ing of simple zone v and zone vi extensor tendon repairs: A
prospective, randomized, controlled study, Plast Reconstr Surg
115:482–487, 2005.
27. Catalano LW 3rd, Gupta S, Ragland R 3rd, et al: Closed treat­
ment of nonrheumatoid extensor tendon dislocations at the
metacarpophalangeal joint, J Hand Surg (Am) 31:242–245,
2006.
28. Purcell T, Eadie PA, Murugan S, et al: Static splinting of exten­
sor tendon repairs, J Hand Surg (Br) 25:180–182, 2000.
29. Hame SL, Melone CP Jr: Boxer’s knuckle. Traumatic dis­
ruption of the extensor hood, Hand Clin 16:375–380,
2000.
30. Scheker LR, Langley SJ, Martin DL, et al: Primary extensor
tendon reconstruction in dorsal hand defects requiring free
flaps, J Hand Surg (Br) 18:568–575, 1993.
31. Evans RB, Burkhalter WE: A study of the dynamic anatomy
of extensor tendons and implications for treatment, J Hand
Surg (Am) 11:774–779, 1986.
32. Newport ML, Tucker RL: New perspectives on extensor tendon
repair and implications for rehabilitation, J Hand Ther
18:175–181, 2005.
33. Elliot D, McGrouther DA: The excursions of the long extensor
tendons of the hand, J Hand Surg (Br) 11:77–80, 1986.
34. Sharma JV, Liang NJ, Owen JR, et al: Analysis of relative
motion splint in the treatment of zone VI extensor tendon
injuries, J Hand Surg (Am) 31:1118–1122, 2006.
35. Hirasawa Y, Katsumi Y, Akiyoshi T, et al: Clinical and micro­
angiographic studies on rupture of the EPL tendon after distal
radial fractures, J Hand Surg (Br) 15:51–57, 1990.

355
CHAPTER
33 
SAGITTAL BAND INJURIES—
PRIMARY AND SECONDARY
MANAGEMENT
Kristen E. Fleager, MD, Monina Copuaco, OTR, CHT, and
James Chang, MD
side of the index finger and ulnar side of the small finger
differ, in that they do not blend with the DTML. The
insertion of the sagittal band is dorsal and tendinous,
and glides with the extensor system as the digits move.
The fibers superficial to the extensor digitorum com­
munis (EDC) tendon are thinner than the deep fibers,
especially in the central digits. The radial component of
the sagittal band is typically thinner and longer than the
ulnar component, explaining the predilection for radial-
sided injury.
The primary functions of the sagittal band are to help
extend the proximal phalanx and to stabilize the exten­
sor tendon in the midline over the dorsal aspect of the
MCP joint.3 The force displacing the tendon in the ulnar
direction is greatest in full extension, decreases from 0
to 60 degrees, and then increases again from 60° to 90°
of flexion.4 Significantly higher forces are required to
prevent additional displacement of an already ulnarly
displaced tendon, and it tends to displace further with
additional MCP flexion.
The long finger is most frequently involved5, likely
because the tendon to the long finger sits on top of the
transverse fibers with a relatively loose fibrous attach­
ment, and the long finger extensor hood attaches
more distally from the joint than that of the adjacent
tendons.6 In addition, the cross-sectional shape of the
extensor tendon of the long finger over the MP joint is
rounder and less anchored than that of the other exten­
sor tendons at that level.7 The injury is most often
located on the radial side, with subsequent displace­
ment of the extensor tendon in an ulnar direction.
Young and Rayan8 studied the anatomy and biome­
chanics of the sagittal band in 48 cadaveric digits and
concluded the following: (1) extensor tendon instability
following sagittal band disruption is most common in
the long finger and least common in the small finger;
(2) ulnar instability of the extensor tendon is due to
partial or complete radial sagittal band disruption, (3)
the degree of extensor tendon instability is determined
OUTLINE
Sagittal band injuries have many potential etiologies,
although rheumatic disease and trauma are the most
common. Open acute injuries with a suspicion of sag­
ittal band laceration should be expeditiously explored.
There is evidence to suggest that closed acute injuries
(less than 3 weeks) may do well with conservative
management consisting of immobilization followed
by protected motion. Patients who fail nonoperative
management or have chronic injuries (3 weeks or
longer) may be appropriate surgical candidates for
primary repair. If there is not sufficient tissue for
primary repair, a reconstructive approach using local
tendon tissue should be undertaken.
Subluxation or dislocation of the extensor tendon at the
metacarpophalangeal (MCP) joint is typically seen in
patients with rheumatoid arthritis but may also be seen
with trauma, congenital laxity of the sagittal band, infec­
tion, and iatrogenic injury. Spontaneous sagittal band
disruption has also been reported.1 A sagittal band
injury will often present with pain and swelling near the
MCP joint, with associated subluxation, or catching. The
radial sagittal band is typically damaged, with resultant
ulnar deviation of the involved finger. The long finger
is most frequently involved. Treatment options are mul­
tiple and include splinting, realignment with direct
repair, and various forms of tendon reconstruction.
ANATOMY AND BIOMECHANICS
The sagittal band is one component of the extensor reti­
nacular system, which forms a cylindrical tube with the
palmar plate (Figures 33-1 and 33-2). This tube sur­
rounds the metacarpal head and MCP joint.2 In the
central digits, the origin of the sagittal band is palmar
and blends with the palmar plate, flexor tendon sheath,
proximal annular pulley, and deep transverse metacar­
pal ligaments (DTML). The sagittal bands on the radial

356
Section 4:  Extensor Tendon Repair and Reconstruction
by the extent of sagittal band disruption, (4) proximal
rather than distal sagittal band compromise contributes
to extensor tendon instability, (5) great forces are
inflicted on the sagittal band while the MCP joint is in
full extension or less frequently in full flexion, which
may be the mechanism of its injury, and (6) wrist flexion
contributes to extensor tendon instability after sagittal
band disruption and may exacerbate the severity of its
injury.
Ishizuki reported on differences in anatomical intra­
operative findings, depending on if the injury was spon­
taneous or traumatic (Figure 33-3).1 Spontaneous
dislocations involve rupture of the superficial layer of
the sagittal band just radial to the extensor tendon,
while traumatic dislocations rupture both layers of the
Figure 33-1  Depiction of sagittal bands and surrounding structures.
DIP
DIP
PIP
PIP
MP
MP
Central slip
Sagittal band
Transverse
retinacular
ligament
Triangular
ligament
Lateral
band
Lumbrical
Central slip
extension
Sagittal
band
Dorsal volar
interosseus
Oblique
retinacular
ligament
Figure 33-2  Cadaver dissection demonstrating sagittal
bands (arrows) and surrounding extensor retinacular system.
Figure 33-3  A, The extensor apparatus at the level of
the MCP joint (transverse section): (1) extensor tendon;
(2) superficial layer of sagittal band; (3) deep layer of the
sagittal band; (4) loose connective tissue between the
sagittal band and dorsal capsule; (5) dorsal capsule. In the
spontaneous type of dislocation, the thin superficial layer of
the sagittal band is ruptured just radial to the extensor
tendon (arrow), and the extensor tendon is detached from
the radial and palmar connection with the deep layer of the
sagittal band. B, In the traumatic type of dislocation, both
layers of the sagittal band are ruptured usually at a site
several millimeters radial to the extensor tendon (arrow).
A
Radial
1
3
4
2
5
Ulnar
B

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Chapter 33:  Sagittal Band Injuries—Primary and Secondary Management
CLASSIFICATION
Rayan and Murray12 described three clinical types of
sagittal band injuries. Type I injury is a contusion
without tearing of the retinaculum, and demonstrates
no instability. Type II is a moderate injury with extensor
tendon subluxation, while type III is a severe injury with
tendon dislocation (Figure 33-5). Subluxation was
defined as “lateral displacement with painful snapping
of the extensor tendon with its border reaching beyond
the mid-line, but remaining in contact with the condyle
during full MP joint flexion.” Dislocation was defined
as “displacement of the tendon in the groove between
the two metacarpal heads.”
DIAGNOSIS
Diagnosis of a sagittal band injury is primarily based on
clinical findings and can be identified with a thorough
review of history and physical examination. Closed
injuries typically present with pain, swelling, and/or
ecchymosis of the involved MCP joint. Open injuries
will involve a laceration over the MCP joint, typically
on the radial side. The extensor tendon may dislocate
ulnarward into the intermetacarpal space, and the
patient may complain of catching, locking, or snapping.
It should be noted, however, that tendon displacement
is often be obscured by swelling. Partial ruptures of the
radial sagittal band will not present with subluxation of
the extensor tendon. Active extension may produce
ulnar angulation of the MCP joint and supination of the
finger. With time, the ulnar deviation deformity pre­
vents dorsal relocation of the extensor tendon, and the
patient may be unable to extend the joint (Box 33-1).
DIFFERENTIAL DIAGNOSIS
Metacarpal fractures and avulsion injuries may present
with swelling and pain about the MCP joint and should
be ruled out. Radiographs may include an anteroposte­
rior (AP), lateral, and Brewerton view (AP tangential
view of the metacarpal heads, used to visualize the bony
origin of the collateral ligaments) (Figure 33-6). Col­
lateral ligament injury will demonstrate instability with
sagittal band several millimeters radial to the extensor
tendon.
CAUSES
The causes of sagittal band injuries are multiple, and
include degenerative disease, trauma, congenital, infec­
tion, and iatrogenic injury.9,10 Rheumatoid arthritis is
the most common cause of subluxation or dislocation
of the extensor tendon at the MP joint. It is most fre­
quently seen in advanced cases with ulnar deviation
(Figure 33-4) but may also be seen in cases without
severe deformity. Rheumatoid arthritis causes synovitis
of the MCP joint, which then leads to attenuation or
rupture of the sagittal bands. Traumatic injury may
involve a laceration of the hood, direct blow, or forced
flexion of the MCP joint. In a closed injury, the finger
is often forced into a flexed and ulnarly deviated posi­
tion against a tense extensor muscles, causing a tear in
the radial sagittal fibers. “Boxer’s knuckle,” a direct
impact over the MCP joint with a clenched fist, has also
been described as a mechanism of injury. Spontaneous
subluxation secondary to an underlying laxity of the
joint capsule may occur during simple activities of daily
living. The rare case of congenital extensor tendon sub­
luxation involves an ulnar drift of all the fingers, and is
sometimes part of the entity known as a “windblown
hand.”11
Infectious etiologies, such as from a human fight bite,
can cause destruction of the joint capsule, extensor
tendon and deep fascial spaces. Iatrogenic injury to
the sagittal band, such as during joint replacement or
MCP joint capsulotomy, may also occur. Such injury
may be avoided by completing the capsulotomy on the
ulnar aspect of the MCP joint, as opposed to the radial
side. Chronic myoclonic jerks in a patient with focal
epilepsy have also been reported to cause extensor
tendon dislocation.
Figure 33-4  Severe ulnar drift of the fingers in a patient
with rheumatoid arthritis.
Figure 33-5  Three types of sagittal band injury: type I,
mild injury with no instability; type II, moderate injury with
extensor tendon subluxation; and type III, severe injury with
tendon dislocation.
I
III
II

358
Section 4:  Extensor Tendon Repair and Reconstruction
lateral stress when the MCP joint is fully flexed. Pain
will be located deep in the groove between the metacar­
pal heads. Sagittal band injuries, in contrast, will dem­
onstrate instability with the MCP joint in extension and
be associated with more superficial tenderness. Radio­
graphs are essential, which may demonstrate bony
avulsion. Trigger finger will present with snapping or
locking, but will be present on the volar aspect of the
hand. Tenderness will be elicited directly over the A1
pulley. Snapping junctura tendinum simulating radial
sagittal band rupture has also been reported, and should
be considered.13
TREATMENT METHODS
Open injuries should be emergently explored, thor­
oughly irrigated, and repaired. Closed injuries have
multiple treatment options, which include splinting,
realignment with direct repair, and various forms of
tendon reconstruction. Patients with an acute traumatic
dislocation may achieve satisfactory results with exten­
sion splinting of the MCP joint.14,15 Those who fail con­
servative treatment or who have a chronic dislocation
may benefit from surgical intervention. Koniuch and
colleagues demonstrated instability in lacerations
involving greater than two-thirds of the proximal sagit­
tal band, and recommended surgery for such injuries16
(Box 33-2).
Rayan and Murray12 described treatment options
based on their classification scheme and the chronicity
of the injury. Acute (within 3 weeks) sagittal band inju­
ries are initially treated with a buddy splint (for type I)
or palmar splint (for types II and III) for 3 weeks, fol­
lowed by protected range of motion 3 times daily for an
3 additional weeks. Buddy splinting is then continued
for 4 additional weeks while completing both active and
Figure 33-6  The Brewerton view is a tangential view of the
metacarpal heads that is useful in detecting fractures,
dislocation, or subluxation of the MCP joint.
60°
Sagittal band injuries are typically on the radial side, leading
to ulnar displacement of the extensor tendon.
The long finger is most commonly involved.
Possible mechanisms of injury:
 Rheumatoid arthritis
 Finger forced into flexed and ulnarly deviated
position
 “Boxer’s knuckle”: direct impact over MCP joint with
clenched fist
 Spontaneous: during mild activity such as flicking or
snapping
 Infection (e.g., fight bite)
 Iatrogenic (e.g., during joint replacement, MCP
capsulotomy)
 Focal epilepsy
Congenital cases are rare but may present with an ulnar
drift of all of the fingers.
Presents with pain, swelling, and/or ecchymosis over
MCP joint. Tendon displacement may be obscured by
swelling.
Patient complains of snapping, locking, or catching.
Partial ruptures of a sagittal band will not present with
tendon subluxation.
Do not confuse a sagittal band injury with:
 Metacarpal fracture or avulsion injury (rule out with
radiograph)
 Collateral ligament injury (will demonstrate instabil­
ity with lateral stress when MCP joint fully flexed)
 Trigger finger (snapping and tenderness will be
present on volar aspect of hand)
 Subluxation of the MCP joint
 Snapping of the junctura tendinum
Box 33-1
Clinical Pearls: Diagnosis
Nonsurgical treatment: Closed acute injuries (<3 weeks)
may be treated initially with splinting.
Surgical indications: Chronic injuries (≥3 weeks), patients
who do not respond to nonoperative treatment, open
injuries with lacerations involving greater than two-
thirds length of the sagittal band.
Surgical methods
 If sufficient tissue is present, perform direct repair.
 Reconstructive options are reserved for patients with
scarring or deficient tissue.
 Sagittal band reconstructions utilizes local tissues
such as juncturae tendinae or a portion of the exten­
sor tendon.
 “Boxer’s knuckle” injuries are best treated with
primary direct repair of the sagittal band, without
capsular repair.
Box 33-2
Clinical Pearls: Treatment

359
Chapter 33:  Sagittal Band Injuries—Primary and Secondary Management
therefore concluded that all acute dislocations less than
2 weeks old should be initially treated with splinting.
A buddy splint immobilizes the injured digit to the
adjacent digit on the side of sagittal band injury (Figure
33-8). It works to minimize abduction forces, and
should fasten proximal to the PIP joint. Both MCP
palmar splints and buddy splints can be used for
nonoperative treatment, or as part of a postoperative
protocol.
Ragland and colleagues18 demonstrated success in
nonoperative treatment of closed sagittal band injuries
in nonrheumatoid patients with extensor tendon dislo­
cations. Patients were treated for 8 weeks with a sagittal
band bridge splint (Figure 33-9). This splint holds the
MCP joint in 25° to 35° of hyperextension, centralizing
the extensor tendon while the sagittal band heals. Active
motion of the DIP and PIP joints was encouraged.
Surgical Options
Surgical options are varied, depending on the complex­
ity of the injury. Simple, acute lacerations involving
greater than two-thirds of the sagittal band or with
associated subluxation may undergo realignment and
passive range of motion exercises. Chronic injuries
(longer than 3 weeks) are treated with buddy splinting
for 6 to 8 weeks. Patients with type II or III injuries, who
do not respond to nonoperative treatment, are then
candidates for surgical intervention. In their series of 28
nonrheumatoid patients, those treated within 3 weeks
of injury achieved satisfactory results with nonoperative
treatment.
Immobilization
MCP palmar splints should position the joint at a
neutral abduction-adduction position, and allow no
more than 20° of active MCP flexion (Figure 33-7). It
should allow motion at the IP joint, which prevents
stiffness. The splint may also be made in slight deviation
in the direction of the sagittal band injury (typically
radial), to decrease tension. Inoue and Tamura17 reported
on six patients seen within 2 weeks with traumatic
or spontaneous dislocations of the extensor tendons.
These patients were treated with a splint that stopped
MCP flexion at 10° to 20° but allowed active extension.
The IP joint was left free. All patients had full range
of motion and were free of symptoms. The authors
Figure 33-7  A–D, A flexion-block splint allows active extension but prevents flexion of the MCP joint past 20°. Motion of
the IP joint prevents stiffness.
A
B
C
D

360
Section 4:  Extensor Tendon Repair and Reconstruction
Wheeldon20 reported using junctura tendinum to
reconstruct the radial sagittal band of the long finger.
The junctura tendinum is separated from its attachment
to the ring finger tendon and brought over to be sutured
in the line of the torn aponeurosis, preventing further
dislocation. However, use of the junctura tendinum may
primary repair with 4-0 braided suture (Figures 33-10
and 33-11). Congenital or spontaneous cases with suf­
ficient tissue may also undergo direct repair. Both Kettle­
camp and Ishiuki have reported good results with a
minimum follow-up of 1 year with direct repair.1,7 The
ulnar sagittal band may also be released to help central­
ize the EDC tendon.
Hame and Melone19 reported on eight professional
athletes with 11 “boxer’s knuckle” injuries who were
treated with centralization of the extensor tendon and
primary sagittal band repair. Seven joints had associated
capsular tears, and these were not repaired. The authors
thought that capsular repair would place excessive
tension on the repair and limit range of motion. Post­
operatively, the joint is immobilized at 60° of flexion
for 6 weeks. Five months postoperatively, all athletes
had returned to sports, were symptom free, and had full
range of motion.
If unable to perform a direct repair of the radial sagit­
tal band because of chronicity of injury, scarring, or
deficient tissue, several surgical options are available,
including those described by Wheeldon,20 McCoy,21 and
Carroll.22 A successful surgical repair must meet two
requirements: (1) the tendon must be accurately aligned
over the MCP joint to diminish the forces causing dis­
location to occur, and (2) the repair must be able to
withstand the ulnar forces incurred during flexion of the
joint.
Figure 33-8  A buddy splint immobilizes the injured digit to
the adjacent digit on the side of the sagittal band injury. It
should fasten proximal to the PIP joint.
Figure 33-9  A–C, A sagittal band bridge splint provides
25° to 35° more extension of the MCP joint compared to
the adjacent digits. It helps maintain the EDC tendon in a
reduced position.
A
B
C

361
Chapter 33:  Sagittal Band Injuries—Primary and Secondary Management
not always be possible because of its irregular location,
inadequate length, or complete absence (Figure 33-12).
McCoy and Winsky21 described using a distal slip of
the extensor tendon to reconstruct the sagittal band. A
4-cm dorsal incision is made along the radial side of the
MCP joint, and skin flaps are reflected. Beginning 1 cm
proximal to the joint, the radial third of the extensor
tendon is stripped back to a point 3 mm proximal to the
level of the articular surface of the metacarpal head. A
suture is placed to prevent additional tearing. The strip
is then looped around the lumbrical tendon and sutured
to itself. Prior to placing the suture, tension is carefully
adjusted with the MCP joint at 95° of flexion. The repair
is tested under direct visualization with flexion and
extension of the MCP joint, and tightened as necessary.
Carroll and colleagues22 reported using a distally
based ulnar slip of the EDC to reconstruct the sagittal
band in patients who had previously failed conservative
management. The EDC tendon is first centralized by
releasing the ulnar sagittal band. The ulnar slip of the
EDC is then looped around the radial collateral liga­
ment and carefully tensioned to allow full flexion. The
EDC slip is then sutured to the EDC tendon.
The common themes of the above repairs are: (1)
wide exploration of the sagittal band complex, freeing
the tendon and sagittal band from the underlying
scarred capsule; (2) identification of stout material to
which to anchor the repair; (3) ideally, use of either the
juncturae tedinae or portion of the extensor tendon as
a pedicled tendon graft; (4) release of any tight portion
of the ulnar sagittal band that would cause excessive
ulnar pull; and (5) full range of motion from MCP joint
extension to flexion to test the adequacy of repair.
Postoperatively, the MCP joint is typically immobi­
lized for 4 to 6 weeks. MCP motion is then started with
a goal to regain full flexion. IP motion is started 2 weeks
after surgery. Koniuch16 has recommended the use of
dynamic splinting in the postoperative period. Excessive
stiffness of the MCP joint should be avoided at all costs.
INJURIES TO THE THUMB
Much like the other four digits, the radial component
of the thumb at the MCP joint is more critical to exten­
sor pollicis longus (EPL) stabilization than the ulnar
component.23 Subluxation or dislocation of the EPL
tendon is rare but has been reported. Rheumatoid
arthritis is one potential cause secondary to a bouton­
niere deformity of the thumb. A congenital case of bilat­
eral thumb contracture secondary to dislocation of
extensor tendons over the MCP joint of both thumbs
has also been reported.24 Traumatic damage to the dor­
soradial aspect of the MCP joint, as well as rupture of
the EPL tendon after a distal radius fracture may also
lead to EPL ulnar dislocation.25-27 Treatment of an injury
to the thumb sagittal band is similar to that of the
remaining digits.
Figure 33-10  Preoperative view of patient who sustained a
dorsal hand laceration with suspicion of ulnar sagittal band
injury.
Figure 33-11  A, Exploration demonstrates a complete
laceration of the ulnar sagittal band and underlying capsule.
B, Direct repair of the ulnar sagittal band was possible
because of the early intervention.
A
B

362
Section 4:  Extensor Tendon Repair and Reconstruction
10. Ovesen OC, Jensen EK, Bertheussen KJ: Dislocation to exten­
sor tendons of the hand caused by focal myoclonic epilepsy,
J Hand Surg (Br) 12:131–132, 1987.
11. Posner MA, McMahon MS: Congenital radial subluxation of
the extensor tendons over the metacarpophalangeal joints: A
case report, J Hand Surg (Am) 19:659–662, 1994.
12. Rayan GM, Murray D: Classification and treatment of closed
sagittal band injuries, J Hand Surg (Am) 19:590–594, 1994.
13. Jeon I, Seok J, Choi J, et al: Snapping junctura tendinum to
the small finger simulating radial sagittal band rupture: A
report of two cases, J Bone Joint Surg (Am) 91:1219–1222, 2009.
14. Bunnell S: Surgery of the Hand, Philadelphia/London/Mon­
treal, 1948, JB Lippincott, pp 670–671.
15. Ritts GD, Wood MB, Engber WD: Nonoperative treatment of
traumatic dislocations of the extensor digitorum tendons in
patients without rheumatoid disorders, J Hand Surg (Am)
10:714–716, 1985.
16. Koniuch MP, Peimer CA, VanGorder T, et al: Closed crush
injury of the metacarpophalangeal joint, J Hand Surg (Am)
12:750–757, 1987.
17. Inoue G, Tamura Y: Dislocation of the extensor tendons over
the metacarpophalangeal joints, J Hand Surg (Am) 21:464–
469, 1996.
18. Catalano LW, Gupta S, Ragland R, et al: Closed treatment of
nonrheumatoid extensor tendon dislocations at the metacar­
pophalangeal joint, J Hand Surg (Am) 31:242–245, 2006.
References
Figure 33-12  Methods of extensor hood reconstruction. A, Ulnar subluxation of the EDC tendon caused by a torn radial
sagittal band. B, Primary suture of the radial sagittal band centering the EDC tendon. C, The ulnar juncture tendinum is
released from the adjacent tendon and sutured to the palmar radial sagittal band remnant of the deep intermetacarpal
ligament. D, The distal tendon is splinted on the radial side and wrapped around the lumbrical muscle. E, An ulnar, distally
based slip of the EDC is looped around the radial collateral ligament (RCL).
Lumbrical
RCL
Scarred radial
sagittal band
Ulnar
sagittal
fibers
released
Ulnar
subluxation
Radial
Ulnar
A
Injury
B
C
D
E
Primary suture
(Kettlekamp)
Junctura tendinum
(Wheeldon)
Tendon slip
(McCoy)
Tendon slip
(McCoy)
Tendon slip
(Carroll)
1. Ishizuki M: Traumatic and spontaneous dislocation of exten­
sor tendon of the long finger, J Hand Surg (Am) 15:967–972,
1990.
2. Rayan GM, Murray D, Chung K, et al: The extensor retinacular
system at the metacarpophalangeal joint: Anatomical and
histological study, J Hand Surg (Br) 22:585–590, 1997.
3. Smith RJ: Balance and kinetics of the fingers under normal
and pathological conditions, Clin Orthop Relat Res 104:
92–111, 1974.
4. Hunter JM, Mackin EJ, Callahan AD: Rehabilitation of the Hand
and Upper Extremity, ed 5, St Louis/London/Philadelphia/
Sydney/Toronto, 2002, Mosby, pp 507–512.
5. Araki S, Ohtani T, Tanaka T: Acute dislocation of the extensor
digitorum communis tendon at the metacarpophalangeal
joint, J Bone Joint Surg (Am) 69:616–619, 1987.
6. Kettelkamp DB, Flatt AE, Moulds R: Traumatic dislocation of
the long finger extensor tendon: A clinical, anatomical, and
biomechanical study, J Bone Joint Surg (Am) 53:229–240,
1971.
7. Wheeldon FT: Recurrent dislocation of the extensor tendons
in the hand, J Bone Joint Surg (Br) 36:612–617, 1954.
8. Young CM, Rayan GM: The sagittal band: anatomic and bio­
mechanical study, J Hand Surg (Am) 25:1107–1113, 2000.
9. Andruss RJ, Herndon JH: Ulnar subluxation of the extensor
digitorum communis tendon: a case report and review of the
literature, Iowa Orthop J 13:208–213, 1993.

363
Chapter 33:  Sagittal Band Injuries—Primary and Secondary Management
24. Rudigier J, Karnosky V: Surgical correction of congenital bilat­
eral dislocations of the extensor tendons of the thumb, Hand­
chir Mikrochir Plast Chir 20:89–92, 1988.
25. Churchill M, Citron N: Isolated subluxation of the EPL
tendon. A cause of ‘boutonniere’ deformity of the thumb,
J Hand Surg (Br) 22:790–792, 1997.
26. Cardon LJ, Toh S, Tsubo K: Traumatic boutonniere deformity
of the thumb, J Hand Surg (Br) 25:505–508, 2000.
27. Gong HS, Chung MS, Oh JH, et al: Ulnar subluxation of a
ruptured EPL tendon at the metacarpophalangeal joint: Case
report, J Hand Surg (Am) 34:910–913, 2009.
19. Hame SL, Melone CP: Boxer’s knuckle in the professional
athlete, Am J Sports Med 28:879–882, 2000.
20. Wheeldon FT: Recurrent dislocations of extensor tendons in
the hand, J Bone Joint Surg (Br) 36:612–617, 1954.
21. McCoy FJ, Winsky AJ: Lumbrical loop operation for luxation
of the extensor tendons of the hand, Plast Reconstr Surg
44:142–146, 1969.
22. Carroll C, Moore JR, Weiland AJ: Postraumatic ulnar sub­
luxation fo the extensor tendons: A reconstructive technique,
J Hand Surg (Am) 12:227–231, 1987.
23. Jaibaji M, Rayan GM, Chung KW: Functional anatomy of the
thumb sagittal band, J Hand Surg (Am) 33:879–884, 2008.

364
CHAPTER
34 
TENDON TRANSFERS FOR
EXTENSOR TENDON
RECONSTRUCTION
Lance M. Brunton, MD, A. Bobby Chhabra, MD, and
Mollie O Manley, MD, MS
distal radioulnar joint (DRUJ). The final and most ulnar
sixth compartment encloses the extensor carpi ulnaris
(ECU). This tendon courses through a fibro-osseous
tunnel on the dorsal surface of the distal ulna, creating
a groove that is often evident on plain radiographs of
the wrist.
Extensor tendons are divided into zones of the hand
and forearm, which help to guide treatment. The zones
are numbered from 1 to 9 with odd numbered-zones
largely corresponding to underlying joints. Zone 1 over­
lies the distal interphalangeal joint (DIP) of the four
digits, and zone 9 extends proximal to the musculoten­
dinous junction. The extensor zones of the thumb are
altered because there is one less joint. In the thumb
zone T1 is over the interphalangeal joint (IP) and T3
over the metacarpophalangeal (MCP) joint, whereas in
the other digits the MCP joint would correspond to
zone 5. The carpal level is T5 for the thumb and zone
7 for the other digits.2
Injury or dysfunction of an extensor musculotendi­
nous unit may result from direct laceration, acute closed
rupture, chronic attritional wear, vascular insufficiency,
systemic inflammatory disease, or radial nerve denerva­
tion. There are several clinical scenarios where extensor
tendon injuries cannot be adequately repaired in
primary fashion and may require tendon transfer recon­
struction. A classic example is rupture of the EPL tendon
in association with nonoperative treatment of a distal
radius fracture. When faced with such a scenario, patient
factors such as comorbidities, accompanying injuries,
occupation, and compliance must be taken into account.
Basic principles of tendon transfer surgery remain para­
mount for achieving optimal results. The work of Starr
among injured military personnel in the early twentieth
century established a framework for tendon transfer
surgery and is summarized in Table 34-1.
More recent work has demonstrated that sarcomere
length may be measured in vivo and a single sample
OUTLINE
Upper extremity extensor tendon injuries are often
detrimental to overall hand function and may lead to
significant patient disability. Insufficiency of the wrist,
thumb, and/or digital extensor tendons may be caused
by direct or indirect mechanisms or may be second­
arily attributable to systemic disease or radial nerve
dysfunction. This chapter will provide an overview of
tendon transfer methods to address extensor tendon
insufficiency, alternatives to tendon transfers for
various clinical scenarios, and guidelines for postop­
erative rehabilitation after reconstructive techniques.
The extensor muscles of the wrist and hand are con­
tained within the dorsal aspect of the forearm and are
all innervated by the radial nerve. At the level of the
wrist, the extensor tendons are divided into six com­
partments by tough fibrous septae of the extensor
retinaculum, numbered from radial to ulnar. The first
compartment contains the abductor pollicis longus
(APL) and extensor pollicis brevis (EPB). Anatomic
variation within this compartment includes potential
multiple tendon slips of the APL and a distinctly sepa­
rate compartment for the EPB.1 The second compart­
ment includes the extensor carpi radialis longus (ECRL)
and the extensor carpi radialis brevis (ECRB). The ECRB
is oriented ulnar to the ECRL. The third compartment
houses the extensor pollicis longus (EPL). This tendon
takes a sharp turn radially after it courses distal to the
ulnar aspect of Lister’s tubercle. Within the fourth com­
partment are the extensor digitorum communis (EDC)
and the extensor indicis proprius (EIP). The terminal
branch of the posterior interosseous nerve (PIN) and
accompanying interosseous vessels lie at the floor of this
compartment. The EIP is oriented ulnar to the index
EDC. The extensor digiti minimi (EDM) is the sole
tendon within the fifth compartment at the level of the

365
Chapter 34:  Tendon Transfers for Extensor Tendon Reconstruction
Traumatic extensor tendon injury may be direct or
indirect and further classified as acute or chronic. The
acute treatment of these injuries is covered earlier in this
textbook. Occasionally, the diagnosis is missed or the
injury is neglected, especially in the setting of poly­
trauma, altered mental capacity, or in patients with poor
understanding of a condition or limited access to
medical resources. The chronicity of the condition often
alters the type of treatment that can be rendered. Cases
that would ordinarily be treated by direct repair are
instead addressed by delayed reconstruction, and tendon
transfer surgery is an indispensible option in these clini­
cal scenarios.
The first description of extensor attritional rupture
was a case report of two patients by Vaughn-Jackson in
1948. Both patients had rupture of the ring and small
EDC in proximity to the distal end of the ulna; the
“syndrome” of progressive extensor ruptures from ulnar
to radial now bears the author’s name.6 Almost a decade
later, another case report demonstrated six patients with
attritional extensor ruptures associated with rheumatoid
arthritis (RA). The authors speculated that rupture
resulted from attritional changes caused by localized
rheumatoid synovitis.7 In patients with RA, the ECU
tendon subluxates volarly, the wrist deviates radially,
and the digital extensors course directly over a dorsally
prominent distal ulna.
Radial nerve dysfunction compromises the extension
capabilities of the wrist and hand. The radial nerve
essentially innervates the entire dorsal aspect of the
forearm musculature. The radial nerve proper innervates
the triceps, lateral portion of brachialis, anconeus, bra­
chioradialis, and ECRL. At the level of the elbow, the
radial nerve proper divides into its superficial sensory
branch and the PIN. The PIN innervates the remaining
extensor muscles in the forearm including the ECRB
(with some variability), supinator, APL, EPB, EIP, EDC,
EDM, and ECU. The radial nerve may be injured directly
from a penetrating injury or often indirectly in asso­
ciation with humeral shaft fractures. It may also be
injured iatrogenically during surgical approaches to the
arm. Depending on the level and extent of the nerve
injury, wrist extension, digit extension, and/or thumb
extension may be compromised. Lack of active wrist
extension will severely affect power grip of the hand.
Digit extension is mostly compromised at the level
of the MCP joints because IP joint extension receives
significant contributions from the median and ulnar-
innervated intrinsic musculature (lumbricals and inter­
ossei) of the hand. A variety of tendon transfers have
been described to improve function without creating
imbalance within the hand. In devising an appropriate
transfer, available muscles that can substitute for the lost
function are considered and the above principles of
tendon transfer surgery guide the ultimate choice and
technique.
represents the entire muscle.3 Consequently, transferred
musculotendinous units may be set at a sarcomere
length specific to the muscle being replaced. Friden4
astutely recognized that surgeons typically overtighten
transfers, thinking they will relax over time, when in
reality the sarcomeres are overstretched and only fire at
28% of the maximum force of the muscle. This may in
part account for transfers losing one grade of strength.
Overly tightened transfers become somewhat of a
passive tenodesis.5
Wrist kinematics plays a role in tendon transfer. The
“dart thrower’s” arc, described as combined wrist exten­
sion and radial deviation through combined wrist
flexion and ulnar deviation, is the functional motion for
most activity. It is argued that with some tendon trans­
fers, this motion is either not restored or compromised.
For example, if the flexor carpi ulnaris (FCU) is sacri­
ficed for transfer in a patient with radial nerve palsy, the
dart thrower’s arc may be restricted.
Table 34-1  Principles of Tendon Transfer Surgery
Applicable to Extensor Tendon Reconstruction
Expendable
donor
The choice of tendon for transfer
should not fully compromise existing
normal function.
One tendon for
one function
Splitting a transferred tendon for
separate functions will function only
to the shortest excursion of the
recipient tendons.
Direction
A straight line of pull maximizes
function of the transfer.
Similar excursion
Donor and recipient excursion
should be comparable.
Similar strength
Donor and recipient strength should
be comparable. One grade of
recipient strength will be lost, even
for the most successful transfers.
Joint mobility
Tendon transfers will not function in
the setting of contracted joints. Near
full passive mobility of distal joints
must be established preoperatively.
Synergy
Antagonistic muscles must provide a
stabilizing effect for the recipient.
Tenodesis
Taking advantage of the tenodesis
effect of the hand enhances tendon
transfer function; wrist arthrodesis
should be avoided if possible.
Tissue
equilibrium
Tendon transfers should be delayed
until adjacent bone and soft tissue
injuries are healed and mature.
Power versus
positional motors
Weaker motors are used for position
and stronger motors for power.

366
Section 4:  Extensor Tendon Repair and Reconstruction
follow up of 4.3 years.9 In a similar retrospective case
series, the tendon transfer group trended toward less
extension and decreased strength, so the authors con­
cluded that people requiring more dexterity and power,
such as musicians or surgeons, should have a free tendon
graft.10
Systemic Disease
Extensor tendon ruptures are common in the setting of
inflammatory arthropathies such as RA. The reconstruc­
tive ladder of direct repair, adjacent tendon coaptation,
and tendon transfer is followed. In the setting of RA,
however, tendon failure by attenuation is rarely ame­
nable to direct repair. These patients typically present in
METHODS OF TREATMENT
Traumatic Injury of EPL
Regardless of the mechanism of injury, treatment of an
EPL rupture follows a general algorithm: primary repair
without transposition, primary repair with transposi­
tion, intercalary tendon autograft, tendon transfer, and
thumb IP fusion. Direct repair is clearly the most desir­
able and can be accomplished if tendon retraction is
minimal and the cut ends are healthy. This sometimes
requires a radially directed transposition of the EPL
tendon away from its normal course adjacent to the
ulnar aspect of Lister’s tubercle to achieve increased
length and a more direct line toward the thumb. When
the EPL tendon appears atrophied or degenerative, the
cut ends are debrided until healthy tendon is evident. If
direct repair is impossible even after transposition, an
intercalary tendon autograft may be used. The obvious
disadvantages are that autografts are essentially avascu­
lar and that two repair sites must heal during rehabilita­
tion. The most common available autograft for this
purpose is the palmaris longus (PL), present in approxi­
mately 80%–85% of people. Alternatives include the
long or ring flexor digitorum superficialis (FDS), plan­
taris, or a toe extensor tendon.
Prior to considering a thumb IP arthrodesis as a last
resort, a final option is tendon transfer. In this regard, the
EIP is classically chosen for transfer to the distal cut end
of the EPL. The EIP is a good option for transfer to
the EPL due to its similar line of pull and amplitude.
Prior to harvesting this donor, the patient must demon­
strate independent EIP function by extending only the
index finger while keeping the other digits flexed. Explo­
ration is carried out to identify the ruptured EPL near
the scapho-trapezo-trapezoidal (STT) joint, and once
tendon transfer is deemed appropriate, a transverse inci­
sion is made over the dorsum of the index MCP joint. The
EIP is identified as ulnar to the index EDC and tagged.
Another incision is made proximal to the extensor reti­
naculum in the distal forearm, and the EIP is identified
as the most distal muscle belly in the fourth compart­
ment. The EIP is confirmed as the tagged tendon in the
distal wound. The tendon is cut distally and brought
through the more proximal incision (Figure 34-1). The
EIP is tunneled and coapted to the distal EPL stump by
Pulvertaft weave or directly sutured to the extensor
mechanism at the thumb MCP level (Figures 34-2 and
34-3). The tension should be set in wrist extension so
that the tip of the thumb touches the tip of the index
finger. With passive wrist flexion, the thumb IP joint
should fully extend. The thumb is then immobilized for
4 weeks with 0° IP flexion and 20° of wrist extension.8
A recent study performed by Schaller and colleagues
compared intercalary PL autograft to EIP tendon trans­
fer for EPL reconstruction. They found no major differ­
ence in thumb function or complications after a mean
Figure 34-1  EIP-to-EPL transfer. The EPL rupture is
identified. The EIP is identified over the index MCP joint
(ulnar to the common extensor tendon), transected, and
pulled through the proximal incision.
Figure 34-2  EIP-to-EPL transfer. A tendon passer is used
to pass the EIP through the EPL and a Pulvertaft weave is
created after appropriate tensioning.

367
Chapter 34:  Tendon Transfers for Extensor Tendon Reconstruction
comparable to the ECRB.12 This transfer is sometimes
performed early after a recognized radial nerve palsy, to
maintain wrist extension, maximize the tenodesis effect,
and aid in early retraining, even if later nerve recovery
restores innervation to the wrist extensor muscles. At
the very least, it may help to prevent wrist flexion con­
tracture and aid in power grasp with improved wrist
positioning. An incision is made on the volar-radial
aspect of the mid-forearm over the insertion of the PT
tendon. The PT must be harvested with a long strip of
periosteum and freed proximally to ensure maximum
excursion. The tendon is then passed subcutaneously
around the border of the radius superficial to the BR
and ECRL. The PT is sutured to the ECRB just distal to
the musculotendinous junction. This connection may
be reinforced with a free ECRL tendon graft. The transfer
is tensioned with the wrist in approximately 45° of
extension.13
Occasionally, patients with a low radial nerve palsy
(PIN palsy) affecting only the ECU and/or ECRB may
demonstrate excessive radial deviation of the wrist
during active extension. To address this imbalance, the
ECRL may be transferred to the ECU or ECRB and effec­
tively increase relative ulnar deviation during wrist
extension and subsequently maximize power grasp.
Restoration of Thumb Extension
The classic tendon transfer to restore thumb extension
is PL to EPL. Comparable excursion is obtained and a
delayed fashion after the tendon ends have retracted and
scarred to adjacent tissue. Once full small joint passive
motion is reestablished, the best option is often tendon
transfer. Briefly, the EIP may be transferred to a ruptured
EPL and a long/ring FDS transferred to a ruptured EDC.
If needed, silicone MCP arthroplasties may be per­
formed and rehabilitated prior to a tendon transfer.8
Radial Nerve Dysfunction
The most commonly described series of tendon trans­
fers to address a permanent high (or low) radial nerve
deficit were adopted in response to injuries suffered by
soldiers from the first two world wars. Others have
drawn on their early experience and described adapta­
tions to these procedures with specific goals in mind.
Several of these contributors and their corresponding
transfers of choice are summarized in Table 34-2.
Restoration of Wrist Extension
In high radial nerve deficits, innervation to the ECRL,
ECRB, and ECU is lost and active wrist extension is
absent.11 The pronator teres (PT) is the most reliable
available tendon to address this deficit and is typically
routed to the ECRB for a potentially more centralized
and balanced wrist extension arc. Abrams and col­
leagues confirmed the suitability of the PT by showing
that its muscle fiber length and cross-sectional area are
Figure 34-3  EIP-to-EPL transfer. Depiction of the finished
transfer.
Table 34-2  Common Tendon Transfers for Radial
Nerve Dysfunction
Procedure
Wrist
MCP Joint
Thumb
Boyes
(1960)
PT to
ECRB
FDS (RF) to
EDC
12 FDS (MF)
to EPL
12 FDS (MF) to
EIP
FCR to APL
and EPB
Jones
(1921)
PT to
ECRB/L
FCU to EDC
III-IV, FCR to
EDC II and EIP
FCR to EPL,
EPB, and APL
Merle
d’Aubigne
(1946)
PT to
ECRB/L
12 FCU to EDC
PL to EPB
and APL
12 FCU to EPL
Riordan
(1983)
PT to
ECRB
FCU to EDC
PL to EPL
Starr (1922)
and Brand
(1985)
PT to
ECRB
FCR to EDC
PL to EPL
Tsuge and
Adachi
PT to
ECRB
FCR to EDC
PL to EPL
Tenodesis of
APL to BR

368
Section 4:  Extensor Tendon Repair and Reconstruction
musculotendinous junction. The FCR is then tunneled
subcutaneously toward the dorsal forearm. The FCR is
coapted to several of the thickest EDC tendons by Pul­
vertaft weave, while the diminutive tendons are sutured
to neighboring EDC tendons further distally. Equal ten­
sioning is difficult, but should be done with the wrist
and MCP joints in neutral and the FCR under maximal
pull (Figure 34-4).
combination of thumb abduction at the MCP joint and
extension at the IP joint is achieved with the positioning
of this transfer. It must be first identified that the patient
has a PL tendon, as it is absent in 15% to 20% of the
population. This is determined by having the patient
oppose the thumb to the small fingertip while maxi­
mally flexing the wrist, at which time it is readily evident
or palpable. An incision is made on the dorsal aspect of
the wrist and the EPL is identified and cut at the mus­
culotendinous junction. The EPL tendon is rerouted
from the third extensor compartment across the ana­
tomic snuff box to pass along the radial border of the
thumb metacarpal. The PL is then identified, freed prox­
imally, and cut at the level of the distal wrist flexion
crease. The tendons are coapted by Pulvertaft weave in
line with the thumb metacarpal. Tensioning of this
transfer should be done with the wrist in neutral and
maximum tension on both ends.13
For patients without a PL, the long or ring FDS is used
and may be brought either around the radius or through
the interosseous membrane (IOM) in the distal forearm.
A slip of the brachioradialis tendon may also be an
adequate motor to substitute for EPL function. A last
option is to include the EPL in the FCU to EDC transfer
described next.
Restoration of Digit Extension
While the aforementioned transfers for wrist and thumb
extension are consistent among Brand, Jones, and Boyes,
they all differ in their transfer for restoring digit exten­
sion. Brand chose the flexor carpi radialis (FCR) because
of its proximity to the wrist extensors and its adequate
excursion to power all of the digital extensors simulta­
neously. Critics of the Jones transfer of the flexor carpi
ulnaris (FCU) cite the sacrifice of the most powerful
wrist flexor with ulnar deviation, especially in light of
the more physiological and functional “dart-thrower’s”
arc of wrist motion. This transfer should be avoided in
a manual laborer who requires wrist ulnar deviation for
power grasp activities such as hammering. The Boyes
transfer uses the ring FDS tendon directed through the
IOM for a straighter line of pull and sufficient excursion.
A disadvantage to this technique may be increased scar­
ring and adhesion formation through the IOM and
therefore some have advocated routing the superficialis
tendon around the radius, especially in adults. The long
finger FDS may compromise power grasp less than the
ring FDS, and its architecture resembles that of the
digital extensors to a closer degree.
The Brand transfer for restoring digit extension uti­
lizes the FCR tendon. An incision is made over the distal
volar forearm between the FCR and PL. The FCR is
identified, cut near its insertion and freed proximally to
allow proper excursion and direction. A second longi­
tudinal incision is made in the central dorsal forearm.
The EDC tendons are identified and divided at their
Figure 34-4  Diagram of Brand transfer. (From Trumble TE,
Rayan GM, Baratz M: Principles of Hand Surgery and Therapy,
ed 2, Philadelphia, 2010, Saunders, page 304).
Extensor carpi
radialis longus
Extensor
pollicis
longus
Brand transfer
Extensor
digitorum
communis
Extensor
digitorum
communis
Extensor carpi
radialis brevis
Flexor carpi
radialis
Pronator
teres

369
Chapter 34:  Tendon Transfers for Extensor Tendon Reconstruction
advantages over nerve autograft because of decreased
donor site morbidity, pure motor donors, and shorter
reinnervation distances. In addition, nerve transfers can
be accomplished in situations that tendon transfers are
less advantageous, such as in the presence of significant
joint stiffness.16 Distal motor nerve reconstruction is
more optimal because of dissection and coaptation
away from the zone of injury.17 Furthermore, the brain
is better equipped to adapt to nerve rather than tendon
transfers. For a high radial nerve palsy, branches of the
median nerve in the proximal forearm may be sacrificed
without appreciable compromise of other hand/wrist
function. Redundant branches to the FCR, FDS, and PL
muscles may be used for nerve transfer to the PIN and/
or independent nerve branches to the wrist extensors16
(Figure 34-5). However, one must balance these advan­
tages with the possible risk of injury to uninvolved
donor nerves such as the median and ulnar nerves.
REHABILITATION
The principles of tendon rehabilitation are as important
as the principles of transfer surgery. Traditionally, three
phases of rehabilitation are recognized, each of which
lasts for approximately 3 weeks. An initial period of
immobilization allows early healing and avoids inad­
vertent damage to repair sites during the acute inflam­
matory phase. This is followed by early passive range of
motion to allow further healing and protection of the
repair site while ensuring adequate tendon gliding, min­
imizing scar adhesions, and preventing joint contrac­
ture. During this phase, dynamic extension splints may
be fabricated to provide more reliable passive mobility
while protecting the repair and restricting the urge to
attempt active motion prematurely. Finally, active range
of motion is initiated and the central nervous system is
trained to fire the transferred musculotendinous unit to
The original Jones transfer for digit extension utilized
both the FCU and FCR. Today, some surgeons favor the
stronger FCU over the FCR. A volar-ulnar incision is
made in the distal forearm, and the FCU tendon is cut
just proximal to its insertion at the pisiform and freed
proximally. The distal muscle fibers are excised off the
FCU tendon, debulking it for later use. Another incision
may be made more proximally over the FCU muscle
belly for additional untethering of fascial attachments
to increase excursion, but care must be taken to avoid
the innervation of the muscle at its proximal 2 inches.
A third incision is made over the dorsal forearm, through
which the FCU is passed. The FCU is coapted to the EDC
tendons in a similar fashion to the Brand transfer. Some
surgeons avoid including the EDM during transfer for
fear of overextending the small digit, but it should be
included when a substantial extensor lag exists after the
other EDC tendons have been secured. The FCU tendon
should have a straight line of pull from the medial epi­
condyle to the EDC. The transfer should carefully incor­
porate each digital extensor to keep all four MCP joints
extending uniformly.
Last, the Boyes transfer for digit extension uniquely
passes the donor FDS musculotendinous units through
the IOM. A longitudinal incision is made in the radial
distal forearm to approach the volar aspect of the IOM.
A transverse incision is made in the distal palm in line
with the long and ring fingers. The FDS tendons are
identified, divided proximal to Camper’s chiasma, and
passed subcutaneously to the more proximal incision.
Two large windows are made in the IOM proximal to
the pronator quadratus muscle without violating the
anterior and posterior interosseous vessels. The muscle
bellies of the FDS are then passed through the IOM. An
incision is made on the dorsal forearm and the rerouted
donor tendons are delivered to the dorsal surface. The
long FDS is brought to the radial side of the wrist and
interwoven to the EIP and EPL. The ring FDS is taken
ulnarly and sutured to the EDC. This transfer is ten­
sioned with the wrist in 20° of extension and FDS under
maximal tension with an assistant keeping the patient’s
digits and thumb clenched into a fist.13
TREATMENT ALTERNATIVES
Tendon transfers for radial nerve dysfunction have been
used reliably for almost 90 years, but these procedures
are not without drawbacks. Tendon transfers are a
balance between restoring function and introducing
additional dysfunction. An alternative to sacrificing
“expendable” tendons that is gaining momentum is the
sacrifice of “expendable” nerves. Repair or nerve grafting
of proximal lesions has historically poor results because
of scar infiltration, large reinnervation distances, and
irreversible loss of target motor endplates after 18 to 24
months.14 Some argue that tendon transfers lead to
unnatural ergonomics.15 Nerve transfer has theoretical
Figure 34-5  Median to radial nerve transfer, shown in a
cadaveric forearm. The pledget has been placed under the
two nerve transfers. The distal transfer (left) is a median
nerve branch to the PL sutured to a radial branch to the
ECRB and the more proximal transfer (right) is a median
nerve branch to the FCR sutured to the PIN.

370
Section 4:  Extensor Tendon Repair and Reconstruction
overstressing the repair. Another group compared early
dynamic splinting to static splinting after ECRL to EPL
reconstruction; they found better range of motion,
shorter rehabilitation period, shorter time off work, and
better movement of the thumb.19 A systematic review of
rehabilitation protocols after extensor tendon repair
compared immobilization, early controlled mobiliza­
tion, and early active mobilization. While immobiliza­
tion has led to comparatively inferior results, the
difference between the other two protocols disappears
by 3 months postoperatively.20
SUMMARY
The work of early hand surgeons laid the foundation for
reconstructive alternatives for loss of extensor tendon
function to injury, disease, or nerve impairment. These
techniques are now employed by most well-trained and
technically proficient practicing hand specialists. Recent
contributions have focused on enhancing tendon repair
and accelerating rehabilitative efforts to optimize patient
outcome. We have summarized the classically described
tendon transfers to treat upper extremity extensor dys­
function and challenge the next generation to think of
new ways to address these difficult problems with inno­
vative techniques and rehabilitative protocols.
achieve a different function than it is accustomed to
performing. Extensor lags are common and may be
treated with static night-time extension splinting.
Gradual strengthening and return to vocational and
avocational activities is pursued as tailored to the indi­
vidual patient.
As tendon repair techniques have improved, rehabili­
tative protocols have adapted to shorten recovery time.
Some surgeons now recommend immediate active
range of motion in an effort to speed recovery and
decrease the necessity of secondary tenolysis surgery.
Early active extension protocols are started in the first
few days postoperatively. The postoperative splint is
removed and a custom thermoplastic splint replaces it.
The patient is then instructed to start active extension
out of the splint with increasing frequency as the days
and weeks progress. Another form of accelerated reha­
bilitation is a dynamic splinting protocol. A device is
attached to the splint with a rubber band traction mech­
anism that passively extends the affected joint. A recent
study comparing early active to dynamic splinting pro­
tocols after EPL reconstruction found no difference at 8
weeks between groups.18 The authors theorized, however,
that patients were not as aggressive in their early active
home exercises for fear of doing something wrong or
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in the first extensor compartment of the wrist. A clinical and
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Surg (Am) 35:854–861, 2010.
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Chir 40:160–164, 2008.
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Pederson WC, Wolfe SW, editors: Green’s Operative Hand
Surgery, ed 5, Philadelphia, 2005, Churchill Livingstone–
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ity, Hand Clin 16:131–139, 2000.
15. Lowe JB 3rd, Sen SK, Mackinnon SE: Current approach to
radial nerve paralysis, Plast Reconstr Surg 110:1099–1113,
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16. Brown JM, Tung TH, Mackinnon SE: Median to radial nerve
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nuances, Neurosurgery 66(3 Suppl Oper.):75–83, 2010.
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371
CHAPTER
35 
SOFT TISSUE COVERAGE FOR
EXTENSOR TENDON
RECONSTRUCTION
Michel Saint-Cyr, MD, FRCS(C)
donor site for local flaps applicable to extensor tendon
coverage. Flap selection will ultimately be dictated by
the size and location of the defect, donor site availabil­
ity, and recipient tissue characteristics.
Goals of this chapter will be to outline initial evalu­
ation and management principles in the presence of
exposed extensor tendons of the upper extremity follow­
ing injury. Principles of flap selection and use will
be discussed to provide stable coverage and expedite
rehabilitation and maximize function.
EVALUATION AND TREATMENT
As with any upper extremity–mutilating hand injury,
ruling out other severe systemic injuries is paramount.
Before embarking in a complex reconstruction, the
patient needs to be stabilized and all other life-
threatening injuries need to be addressed and resolved.
Patient-specific factors such as overall general health
condition, associated comorbidities, profession, socio­
economic status, age, and compliance to therapy need
to be considered when selecting the type of reconstruc­
tion. There are also wound-specific factors such as defect
size as well as mechanism of injury, such as crush, pene­
trating versus blunt trauma, amputation, etc. All wound
factors need to be considered as well as the zone of
injury and availability of local or distant tissue for flap
coverage.
WOUND DÉBRIDEMENT
Early radical débridement, of all nonviable tissue under
tourniquet, control is pivotal prior to any attempt at
locoregional or free flap soft tissue reconstruction. The
critical step involves débridement of all marginally and
questionably viable tissue to convert a contaminated
wound into a clean wound and thus minimize risks of
subsequent infection. This also allows a clear evaluation
of all injured and missing structures. Early aggressive
débridement should be performed over traditional
serial débridement whenever possible. Serial débride­
ment can delay final wound closure and make assess­
ment of tissue viability difficult, and trigger a cascade of
OUTLINE
A myriad of options exist for soft tissue reconstruction
and coverage of exposed extensor tendons. This can
range from simple skin grafting with or without turn­
over adipofascial flaps to free flaps in more complex
cases. Principles of proper patient and wound evalua­
tion, radical débridement, early coverage, and rehabili­
tation are paramount to maximize function. Transfer
of intrinsic flap (i.e., flap from the injured the hand)
should be considered first to cover local and small area
soft tissue defect. Local or regional flap such as radial
or ulnar forearm flap, dorsal interosseous artery flap,
or lateral arm flap may be considered to cover the
defect in the dorsum of the hand. Anterior thigh flap
or other vascularized distant flaps should be consid­
ered if the defects are extensive and located over the
dorsum of the hand or forearm. Thorough débride­
ment is required before embarking on complicated
reconstructive procedures, and postoperative motion
of the hand and wrist is important to prevent joint
stiffness and tendon adhesions. Despite increased
technical requirements and length of operation, free
flap reconstruction often results in fewer postoperative
complications due to better vascularization, which is
important when early postoperative mobilization or
adjuvant therapy is required.
Often, extensor tendon exposure, lacerations, or tendon
loss will require coverage with well-vascularized tissue
to promote proper tendon healing and early mobiliza­
tion. Adequate coverage also helps minimize any sub­
sequent scarring, in an environment that is already
prone to significant adhesions and contracture forma­
tion. Therefore, it behooves the reconstructive hand
surgeon to provide well-vascularized tissue with either
an intrinsic, locoregional, or distant free flap to provide
stable soft tissue coverage. The dorsal skin of the hand
has many qualities that allow flexion and extension of
the digits. The increased skin laxity, pliability, and thin­
ness also make the dorsum of the hand an excellent

372
Section 4:  Extensor Tendon Repair and Reconstruction
helps minimize any risk of infection due to the presence
of residual necrotic tissue (Figure 35-1).
TIMING OF RECONSTRUCTION
Reconstruction should be attempted as early as possible
once adequate débridement is achieved. Advantages of
early reconstruction include primary wound closure,
coverage of vital structures, shorter hospitalization
course, avoidance of multiple procedures and multiple
painful dressing changes, and early rehabilitation and
mobilization. An absolute indication for immediate
primary reconstruction includes exposure of recon­
structed or native arteries and veins. Contraindications
for immediate reconstruction include an unstable
patient that cannot tolerate a prolonged operative pro­
cedure, and patients in whom amputation and pros­
thesis would provide a better functional result than
reconstruction.
If delayed reconstruction is selected or necessary,
then all joints must be actively or passively mobilized
to maintain motion. Prolonged use of negative pressure
wound therapy dressings in the hand without passive
and active mobilization is to be condemned as this can
lead to severe stiffness and fibrosis.
SOFT TISSUE COVERAGE AND
RECONSTRUCTION
Intrinsic Flaps
Clearly, if paratenon is available over the exposed exten­
sor tendon, a simple form of coverage can involve either
additional tissue loss from desiccation due to prolonged
dressing changes. Early débridement and reconstruction
also help to achieve the ultimate goal of early mobiliza­
tion and return to function, which is critical in the upper
extremity.
The general assessment is done, ideally, in the operat­
ing room under tourniquet control. The upper extremity
is exsanguinated and a tourniquet is elevated and used
to provide a blood-free field, so as to better expose and
identify potentially devitalized tissue. All devitalized
tissue is then débrided and the wound is extirpated very
much like a tumor from the periphery towards the center
and within well-defined natural tissue planes. The
wound bed is resected entirely thus converting it from
a contaminated to a noncontaminated wound. Follow­
ing wound débridement, and once the extensor tendons
have been either grafted or repaired, healthy coverage
can be provided with either an intrinsic, locoregional,
or free flap, as needed. A major prerequisite is adequate
wound débridement to minimize any risk of infection,
wound breakdown, and flap loss. Any initial wound
that cannot be débrided thoroughly is best débrided
serially after 24 or 48 hours. A negative pressure dressing
can be applied temporarily using a white sponge over
exposed extensor tendons so as to minimize any risk of
desiccation. Note that negative pressure therapy should
be used sparingly and only as a temporizing measure
prior to definitive closure, which should be performed
ideally within the first week. The upper extremity is
very sensitive to the timing of reconstruction, and any
prolonged immobilization will have a definite negative
impact on final range of motion due to progressive
stiffness, joint contracture, and swelling. Early coverage
allows patients to enter an aggressive rehabilitation
program to maximize their range of motion.
Once the wound has been properly débrided, the
tourniquet is released and all nonbleeding and nonvi­
able tissue is reexcised. Wound edges are inspected for
bright red bleeding, and the wound is irrigated with a
bulb syringe only. Pulse lavage is not used and can lead
to extensor tendon friability and additional soft tissue
trauma. Therefore, we only use triple antibiotic saline
with bulb irrigation.
Choice of extensor tendon coverage, working from
distal to proximal, will be based on the level of injury
as well as the availability of nontraumatized soft tissue
in the proximity of the wound. Clearly, replacing like
with like is the ideal condition. All defects that are
replaced with local tissue of similar color, texture, pli­
ability, and sensation will provide a better outcome than
non loco-regional flaps. The resulting defect, following
radical débridement, will also be much larger than the
initial wound size. Knowing that stable soft tissue cover­
age can be provided regardless of defect size should be
impetus for providing aggressive initial débridement.
This not only serves to expedite reconstruction but also
Figure 35-1  Dorsal hand soft tissue defect following
first-stage radical débridement, under tourniquet control.
This wound was clean enough to be covered.

373
Chapter 35:  Soft Tissue Coverage for Extensor Tendon Reconstruction
a split- or full-thickness skin graft, which is harvested
from the either the forearm, the hypothenar region or
groin. Note that skin grafts harvested further from the
defect will be less cosmetically matched compared to
more local skin graft options. Skin grafts harvested from
the hand or from the forearm would provide better skin
match compared to more distant skin grafts such as the
proximal forearm, or groin.
Turnover and Distally Based Adipofascial Flap
If the exposed extensor tendon is devoid of paratenon,
then a skin graft is not an option. A simple form of
reconstruction can include a turnover adipofascial flap,
which can be used to cover small-to-moderate sized
defects. These are then covered with a split-thickness
skin graft. Adipofascial flaps can be very useful for resur­
facing small exposed extensor tendon defects in the
digits as well as the dorsum of the hand. These can flaps
can be based off of small perforators from the dorsal
metacarpal arteries when covering defects in the hand
or dorsal digital branches when covering dorsal digital
defects. These can be wide based and are simply turned
over under elevated skin flaps and skin grafted to provide
well-vascularized coverage over the exposed extensor
tendons. Turnover adipofascial flaps need to be widely
based to maximize perforator incorporation into the
flap, as well as subcutaneous veins. When covering
digital defects, the flap is distally based and incorporates
a maximal amount of arterial perforators and subcuta­
neous veins for venous outflow. Closure of the skin flaps
that have been elevated should not be performed under
any tension, so as to minimize any risk of venous con­
gestion of the adipofascial turnover flap. These flaps are
simple to elevate, provide quick and easy coverage
options for small defects with exposed tendons, and
offer minimal morbidity to the donor site.
Reverse Cross-Finger Flap
Extensor tendon exposure in zones 1 through 4 can be
covered with reverse cross-finger flaps. The reverse cross-
finger flap, first described by Pakiam in 1978, is an
excellent local flap for soft tissue coverage of exposed
extensor tendons in the dorsal digit. Its vascular supply
is provided by the dorsal digital branches of the digital
arteries, as well as small subcutaneous veins and venae
comitantes from the dorsal digital branches. Subcutane­
ous veins from the cross-finger flap can also be used as
venous flow through veins for replants to bridge both
recipient and donor veins. The reverse cross-finger flap
is then covered with either a split- or full-thickness skin
graft for definitive coverage. The flap is elevated as
follows: The adjacent donor digit is used for a cross-
finger flap. The mid-axial skin incision is made proximal
to the defect, and the skin flap is elevated just above the
subcutaneous tissue in a direction that is opposite the
side of the defect. The adipofascial flap is then harvested
down through paratenon in the opposite direction of
the elevation of the overlying skin flap. This is taken
from mid-axial line to mid-axial line. Care is taken to
not damage any of the dorsal branches of the digital
artery when harvesting this flap. The flap is then turned
over to cover the adjacent digit dorsal defect and provide
good coverage for the exposed extensor tendon. The
cross-finger adipofascial flap is covered with a split-
thickness skin graft and the donor site is closed primar­
ily with its hinged skin flap. The hand is immobilized
for 2 to 3 weeks, preferably 3 weeks, and the division
and inset of the flap is performed after 2 to 3 weeks,
with revisions to the donor or recipient site as needed.
The patient is splinted in a position of function for 3
weeks to minimize any contractures. In compliant
patients, the patient can begin light active range of
motion after the surgery but needs to be very compliant
(Figure 35-2).
Metacarpal Artery Island Flaps
The dorsal aspect of the hand represents an invaluable
and expendable donor site for dorsal digital coverage of
exposed extensor tendons. A sound knowledge of the
vascular anatomy of the hand and digits’ dorsal skin has
led to many innovative flap designs for this area. This
knowledge is an important prerequisite for the safe
application of these flaps. The blood supply to the
dorsal skin of the hand and digits is provided by (1) the
dorsal metacarpal arteries, which vascularize the proxi­
mal portion of the hand and (2) the dorsal perforating
metacarpal arterial branches from the deep palmar arch,
which supply the distal hand and proximal phalanx.
These two major arterial systems form the basis for
direct and reverse dorsal metacarpal artery (DMA) flaps.
First Dorsal Metacarpal Artery Flap
The first dorsal metacarpal artery flap (FDMA flap, i.e.,
kite flap), described by Foucher and Braun,1 provides two
major applications in hand reconstruction: (1) dorsal
hand wound coverage and (2) thumb reconstruction.
In Foucher’s anatomical study of 30 injected cadav­
eric hands, the FDMA originated from the radial artery
in 28 of 30 specimens and from the dorsalis superficialis
antebrachialis artery in 2 of 30 cases. From there, it
courses distal to the extensor pollicis longus tendon,
and proximal to the radial artery’s entry between both
heads of the first dorsal interosseous (DIO) muscle. The
FDMA travels parallel to the dorsal surface of the second
metacarpal, and superficial to the first DIO muscle
fascia, with some fibers occasionally covering the vessel.
The FDMA then continues distally and anastomoses
at the level of the metacarpal neck with dorsal perfor­
ating branches from the palmar metacarpal arteries
of the deep palmar arch. These perforator branches
form the basis of the reverse flow FDMA island flap.
They anastomose with three different arterial systems:

374
Section 4:  Extensor Tendon Repair and Reconstruction
(1) distally with the dorsal branches of the proper
palmar digital arteries, (2) proximally with branches of
the DMA, and (3) laterally with adjacent DMA perforat­
ing branches (Figure 35-3).
The FDMA flap is designed over the dorsum of the
index finger’s proximal phalanx along the mid-radial
and mid-ulnar lines of the finger (see Figure 35-3).
Distal and proximal limits include the proximal inter­
phalangeal (PIP) joint and metacarpophalangeal (MCP)
joint, respectively; however, an extended flap can also
be harvested by including skin from the dorsum of the
middle phalanx. Inclusion of the dorsal skin of the MCP
joint can make dissection of the pedicle safer because
the layer of subcutaneous tissue is very thin at this level.
A lazy S, or Bruner-type incision, is marked from the
head of the second metacarpal bone to the apex of the
first interosseous web space. This design allows for gen­
erous exposure and an en block dissection of the pedicle
without skeletonization and undue risks of vascular
damage.
Elevation of the FDMA flap begins distally by incising
the flap outline over the dorsal proximal phalanx in a
radial to ulnar direction, just above the paratenon layer.
The lazy S, or zigzag incision, is made and the lateral
skin flaps are raised subdermally to develop a subcuta­
neous pedicle. Sensory branches of the radial nerve and
one or more subcutaneous veins are identified proxi­
mally and included in the pedicle. The radial border of
the second metacarpal bone is then exposed and dissec­
tion continues deeper to include the first dorsal inter­
osseous muscle fascia. This fascia is sharply incised
and carefully dissected off the interosseous muscle in a
radial direction, until the ulnar border of the first meta­
carpal bone is reached. The FDMA lies just superficial
to the first dorsal interosseous fascia, thus requiring
inclusion of the latter during flap elevation to prevent
damage to the pedicle. For this same reason, some
authors even advocate raising a cuff of first dorsal inter­
osseous muscle in case the FDMA lies deeper. Pedicle
dissection continues in a proximal direction and all
small perforating branches penetrating the interosseous
fascia are coagulated to yield a maximal pedicle length,
which can vary from 6 to 8 cm. The pedicle is raised
with a generous cuff of subcutaneous fibrofatty tissue
without skeletonization. If required, tunneling is created
by undermining subcutaneous skin, and the flap is
transferred into the defect without tension, compres­
sion, or kinking. Nevertheless, when harvesting an
FDMA flap, an overlying skin bridge over the pedicle
should also be harvested so as to avoid tunneling and
possible pedicle compression. We perform this for all
intrinsic pedicle flaps. The arc of rotation of the FDMA
flap allows it to reach the thumb tip, volar second MCP
joint, distal antebrachial region, and fifth MCP joint.
The donor site is covered with a full-thickness skin graft
(see Figure 35-3).
Figure 35-2  Step-by-step description of a reverse cross-
finger flap elevation. Either a thin split-thickness or full-
thickness skin graft can be used to cover the wound.
Intact
skin
island
Defect
Reversed flap covering
recipient defect and
reconstructing avulsed
eponychial defect
Thin
full-thickness
skin graft
Elevated thin
full-thickness
skin flap
Elevated
full-thickness
subcutaneous
flap with intact
skin island
A
B
C
Originally elevated
thin full-thickness
skin flap covering
donor defect

375
Chapter 35:  Soft Tissue Coverage for Extensor Tendon Reconstruction
entire second web space for reconstruction of thumb
degloving injuries.
The SDMA generally runs along a line joining the
anatomical snuffbox and second web space. In 23 of
29 (79%) cadaveric hands studied by Early and Milner,
the SDMA originated from the dorsal carpal arch. In the
remaining six specimens, the SDMA originated from the
deep palmar arch, the FDMA, the anterior interosseous
artery, or the radial artery. The SDMA passes deep to the
extensor digitorum and extensor indicis muscles of the
index finger, and superficial to the second dorsal inter­
osseous muscle fascia. As the SDMA reaches the second
The first dorsal interosseous muscle fascia must be
included in flap elevation to avoid inadvertent injury
to the FDMA. The pedicle should not be skeletonized
and should be raised with a generous cuff of fibrofatty
tissue.
Second Dorsal Metacarpal Artery Flap
The second dorsal metacarpal artery (SDMA) flap is a
reliable sensate flap with a wide arc of rotation.2-4 Like
the FDMA flap, it serves as a useful and reliable tool for
coverage of hand and thumb defects. This flap can be
combined with the FDMA island flap to harvest the
Figure 35-3  A, Dorsal tissue defect of left thumb with exposed phalanges and loss of extensor pollicis longus tendon.
B, Harvest of a 3.0 × 5.5-cm flap based on the dorsal metacarpal artery with a skin island kept over the pedicle to avoid
tunneling the flap and compression to the flap and vascular compromise. C, The FDMA flap was harvested over the first and
second interosseous muscle with incorporation of the fascia to not injure the pedicle. A wide base of subcutaneus tissue of
the flap was harvested to maximize arterial inflow and venous outflow. The skin paddle can be extended passing the PIP joint
for a longer flap, and this flap can also be made sensate by including a dorsal branch of the ulnar or radial digital nerve, or the
digital nerves of the thumb. D, Final inset of the FDMA flap with well-vascularized coverage over the thumb. Note that the
FDMA flap is not tunneled. The donor site is covered with a full-thickness skin graft.
A
B
C
D

376
Section 4:  Extensor Tendon Repair and Reconstruction
are elevated in a subdermal plane with appropriate
superficial veins and branches of the radial nerve. Dis­
section is deepened along the ulnar aspect of the
index extensor tendons. After radial retraction of these
tendons, the SDMA can be seen coursing over the second
dorsal interosseous muscle and fascia. The SDMA
pedicle is dissected from the second dorsal interosseous
muscle much like the FDMA (i.e., with a generous cuff
of fascia and muscle), until the flap safely reaches its
intended destination. The donor site is closed primarily
or with a full-thickness skin graft.
As in the dissection of the first dorsal metacarpal
artery flap, the second dorsal interosseous fascia should
be included during the elevation of an SDMA flap to
avoid inadvertent injury to the SDMA. In addition, the
pedicle should not be skeletonized and should be
raised with a generous cuff of fibrofatty tissue to mini­
mize risks of venous congestion, vasospasm, and vascu­
lar injury.
Perforator-Based DMA Flap
As described by Quaba and Davidson,5 the reverse flow
dorsal metacarpal flap can be harvested without incor­
porating the DMA. Dissection of the flap proceeds from
proximal to distal, and is carried above the dorsal inter­
osseous fascia without including the DMA. The flap may
be raised on the second, third, or fourth intermetacarpal
space and is designed as an ellipse, which can extend
from the MCP joint to the wrist crease (Figure 35-4).
web space, one or more large perforators can be found
between the second and third metacarpal heads in the
second intermetacarpal space. These perforators origi­
nate from the deep palmar arch and pass dorsally to
communicate with the SDMA to supply the dorsal skin.
The perforators arise at the level of the metacarpal necks
and give off distal branches, which anastomose with the
dorsal cutaneous branches of the PPD arteries. These
perforator vessels form the basis of the extended SDMA
flap and the reverse flow SDMA flap.
The SDMA runs in an oblique line between the ana­
tomical snuffbox and the center of the second web
space, between the heads of the second and third meta­
carpal bones. Depending on defect size and location,
the flap can be designed over the second intermetacar­
pal space, over the proximal phalanx of the middle
finger, or over the superficial web space. The proximal
intersection of the extensor tendons to the index and
middle fingers can be considered the pivot point of
the flap.
The flap is incised circumferentially and dissected off
the extensor tendon paratenon of the proximal phalanx.
Dissection is performed in a distal-to-proximal fashion.
When the second web space is reached, the communi­
cating perforator from the palmar metacarpal artery
must be identified and ligated. An S-shaped incision is
then made from the base of the flap and carried proxi­
mally over the SDMA toward the anatomical snuffbox
until the required pedicle length is obtained. Skin flaps
Figure 35-4  A, Soft tissue defect in the right long finger with exposed extensor tendon following repair. This defect is an
excellent indication for a perforator-based metacarpal artery flap. In this cased, an SDMA perforator-based flap “Quaba flap”
was used. The same flap can be raised from the third and fourth DMA perforators. B, The axis of the flap was designed parallel
to the third metacarpal and extends from the intermetacarpal head space, to the distal wrist crease, and not beyond this
point. A pinch test is used to estimate the maximal width of the flap. A larger flap can be harvested but the donor site will
require a skin graft.
A
B

377
Chapter 35:  Soft Tissue Coverage for Extensor Tendon Reconstruction
Thumb Dorsal Radial Artery Flap
A thumb dorsal radial artery flap can be used for smaller
defects in the dorsum of the thumb. This is based on
recurrent branches from the radial digital artery. Vascu­
larity is ensured by the communication between both
the ulnar and radial digital arteries of the thumb via
dorsal branches of the digital artery and communicating
branches along the dorsum of the thumb. The flap is
elevated on the dorsal radial aspect of the thumb overly­
ing the MCP joint and is dissected from proximal to
distal, leaving a wide base of fibrofatty tissue along the
pedicle (Figure 35-5). Inset is performed under minimal
tension, and the donor site is either closed primarily or
closed with a skin graft. Any exposed pedicle that cannot
be covered with primary closure should be skin grafted
to minimize any compression. This skin graft can be
excised at a later date, but often the swelling and soft
tissue contracture will minimize any need for revisions
in the future.
Local Flaps
Dorsal hand defects can be either covered with local,
regional, or distant flaps. Many dorsal hand defects with
exposed extensor tendons can be covered with either
The flap width and length can vary from 1 to 3.5 cm
and 2 to 9 cm, respectively. This flap is an excellent
option for dorsal digital coverage. It will easily cover
defects involving exposed MCP joint, proximal phalanx,
and even the PIP joint (see Figure 35-4). This flap is
elevated suprafascially from proximal to distal with the
overlying skin and subcutaneous tissue from the dorsum
of the hand. The axis of the flap is parallel to the meta­
carpals, and dissection is stopped just distal to the junc­
turae tendinum, where a major cutaneous perforator
can be found originating from the dorsal metacarpal
artery. The recurrent cutaneous perforator branch of the
DMA, which communicates with the deep carpal arch
or metacarpal artery at the level of the metacarpal neck,
is found just distal to the intertendinous connections
and represents the pivot point of the flap. The arc of
rotation varies from 0° to 180° and can cover the
dorsum of the metacarpal bone, web space, and dorsal
proximal and middle phalanges, up to the distal inter­
phalangeal (DIP) joint. This modification converts the
standard axial type reverse flap into a reverse perforator
flap via this recurrent branch. The advantages of this
modification include ease of elevation and thinner cov­
erage for dorsal digital defects.
Karacalar and Özcan6 have described a modified
version of the reverse flow dorsal metacarpal flap. Their
flap had an extended arc of rotation and covered the
distal phalanx in five patients. It is based on the
second and third intermetacarpal spaces as well as
connections between the dorsal branches of the digital
artery and the terminal branches of the DMA at the level
of the proximal phalanx. The largest flap size measured
7 × 3 cm. Flap survival rate was 100%. Dissection is
similar to dissection of the Quaba reverse flow dorsal
metacarpal flap but is carried more distally. The perfo­
rating recurrent branch of the dorsal metacarpal artery
is ligated and a pedicle is developed based on connec­
tions between the dorsal branches of the digital artery
and the terminal cutaneous branches of the DMA over
the proximal phalanx. Pedicle skeletonization should
be avoided and a generous cuff of fibrofatty tissue
should be harvested with the flap. Angiographic studies
by Yang and Morris confirm the anatomical basis of this
flap modification.7 This modification allows coverage of
more distal defects at the level of the distal phalanx,
which could not be treated with a standard reverse flap
design.
Care must be taken to harvest the flap while respect­
ing integrity of the paratenon if a skin graft is antici­
pated. The flap inset is performed under minimal
tension. The flap should preferably not be tunneled to
minimize any risk of congestion and ischemia, and
sutures are taken out 2 weeks later, and light active range
of motion is begun after 1 to 2 weeks. This flap is an
excellent option for all exposed extensor tendons within
the digit from the MCP joint to the DIP joint.
Figure 35-5  A, Soft tissue defect in the right thumb with
landmarks drawn for a dorsal radial thumb flap. B, Harvest
of the flap with a large cuff of subcutaneous tissue kept
surrounding the pedicle.
A
B

378
Section 4:  Extensor Tendon Repair and Reconstruction
for exposed defects on the ulnar and dorsal aspect of
the hand.
The flap is raised as an island flap subfascially, and
dissection is started from the ulnar side of the wrist and
forearm from proximal to distal. The pedicle is exposed
by retracting the flexor carpi ulnaris tendon radially and
the major perforator pedicle can be seen emerging from
ulnar artery 2 to 5 cm proximal to the pisiform. The
dorsal ulnar artery is dissected down to the origin of the
ulnar artery to allow rotation of the flap 180° and to
prevent inadvertent pedicle kinking and twisting. For
smaller flaps, the donor site can be closed primarily; if
not, then a split-thickness skin graft is used for closure.
Free Flaps
Free flap reconstruction is now well established for pro­
viding a safe and reliable means of obtaining wound
closure and composite structural repair. With current
success rates of over 95%, and the availability of mul­
tiple donor sites, free flaps offer virtually unlimited
freedom in complex reconstruction of the dorsum of the
hand. Key requirements for soft tissue reconstruction
include provision of a stable bony framework, adequate
recipient vessels outside the zone of injury, adequate
blood supply of tissue adjacent to the recipient site, a
stable patient, and a surgeon experienced in microsur­
gery. Free tissue transfer for extensor tendon coverage is
indicated when local pedicle flaps cannot be harvested
outside the zone of injury or when soft tissue defects are
extensive.
Several key features favor the use of free flaps over
pedicled or local flaps, including avoiding additional
donor site burden or surgical trauma to an already com­
promised region, including avoiding sacrifice of a major
blood vessel, and providing ample well-vascularized
tissue to promote wound healing, minimize infection,
and enable coverage of larger wounds. A composite
reconstruction using vascularized bone, tendon, and
nerve is also generally easier to design. The structural
complexity and aesthetic demands of a recipient site
may also dictate that a graded approach using the recon­
structive ladder is not always appropriate. In these cir­
cumstances, free flap soft tissue reconstruction should
always be considered early in the treatment algorithm if
a better end result can be anticipated. Despite increased
technical requirements and length of operation, free
flap reconstruction often results in fewer postoperative
complications due to better vascularization, which is
important when early postoperative mobilization or
adjuvant therapy is required.
Free flap reconstruction is contraindicated in pati-
ents with significant comorbidities. Diabetes, cigarette
smoking, corticosteroids, and immunosuppressants
may lead to wound healing complications. Presurgical
angiography may be required following high-energy
injuries to the upper extremity where vascular injury is
a pedicle radial forearm flap, posterior interosseous
artery flap, or dorsal ulnar artery flap. These are three
very good options when the forearm has not been
compromised.
Radial Forearm Flap
The flap provides excellent thin and pliable skin
coverage for reconstruction of soft tissue defects of the
dorsal hand. It may be harvested with a vascularized
segment of radius for reconstruction of metacarpal
bone defects and with palmaris longus tendon for
extensor tendon defects. Additional composite recon­
struction is also possible by incorporating antebrachial
cutaneous nerve.
The flap is supplied by the multiple septocutaneous
perforating branches of the radial artery in the forearm,
and flap territory extends from lower third of the volar
aspect of the arm proximally to the flexion crease dis­
tally. Distal width is from the extensor pollicis longus
tendon radially to the extensor carpi ulnaris tendon
ulnarly and proximally from lateral to medial epicon­
dyles. The diameter of the artery is approximately
2.5 mm, and that of the concomitant veins 1.3 to
2.5 mm. The typical radial forearm flap creates rather
marked scar in exposed forearm and need sacrifice of
a main artery truck,8 which became less used than
before, because a myriad of other options are currently
available.
Alternatively, for small to medium-sized defects, a
perforator-based radial forearm flap can also be used
without sacrifice of the radial artery. At least one major
radial artery perforator can be found within 2 cm from
the radial styloid.
Posterior Interosseous Artery Flap
The posterior interosseous flap is also a very credible
option for dorsal coverage. The pedicle can be found
from the lateral epicondyle to run in between the ECU
and the EDQ. Dissection proceeds from proximal to
distal, and identification of the posterior interosseous
artery is found with perforators emanating from the
septum between both the previously mentioned
muscles. Pivot point is just proximal to the distal radio­
ulnar joint, and care must be taken to protect the pos­
terior interosseous nerve during dissection. This flap
will cover small to moderate-sized defects of the dorsum
of the hand and is a viable option when the radial
forearm flap is not available.
Becker Flap (Ulnar Artery Dorsal Perforator Flap)
The dorsal ulnar artery fasciocutaneous flap was first
described by Becker and Gilbert in 1988, which is vas­
cularized by the ascending branch of the dorsal ulnar
artery without sacrifice of the ulna artery.9 The Becker
flap is in essence a pedicle perforator flap based of
the ulnar artery and can provide excellent coverage

379
Chapter 35:  Soft Tissue Coverage for Extensor Tendon Reconstruction
nerves of the arm and forearm. During dissection the
posterior cutaneous nerve of the forearm is usually
sacrificed.
Scapula/Parascapular Flap
The scapula and parascapular flaps afford consistent
vascular anatomy, an easily accessible vascular pedicle,
good vessel diameter and length, and flap safety and
reliability. The flap is also useful for dorsal hand cover­
age hand reconstruction and can also be combined with
the latissimus dorsi or serratus muscle on the same
subscapular system for additional coverage.
Anterolateral Thigh (ALT) Flap
The ALT flap includes a large and reliable adipocutane­
ous territory, minimal donor site morbidity, capability
for sensory neurorrhaphy, long vascular pedicle, and the
potential for flap thinning in the primary or secondary
setting to improve flap contour.10 Multiple components
can be raised on different perforators from the lateral
femoral circumflex artery, including separate skin
paddles, the vastus lateralis muscle, and iliac crest,
enabling accurate reconstruction of complex three-
dimensional multicomponent defects.
The flap is based on the descending branch of the
lateral femoral circumflex artery, located between the
rectus femoris and vastus lateralis muscles, with a per­
forator almost always found at the midpoint of a line
between the anterior superior iliac spine and the supero­
lateral aspect of the patella. The perforator is musculo­
cutaneous in approximately 80% of cases. The pedicle
can be up to 15 cm in length with an average arterial
external diameter of 2 to 3 mm (Figure 35-8).
Flaps in excess of 40 cm in length have been safely
harvested based on only one perforator. Primary closure
can be achieved if the flap width does not exceed 8 to
Figure 35-6  Schematic demonstrating the major
landmarks and pedicle for the lateral arm flap.
Ant. radial
collateral a.
Brachialis m.
Brachioradialis m.
Radial
collateral a.
Radial n. Triceps m.
Posterior radial
collatral a.
Lower lateral
cutaneous n.
of the arm
suspected or in patients with extensive atherosclerotic
disease.
The availability of free flap donor sites is extensive
and selection should involve not just coverage but
should be tailored and individualized to meet the recip­
ient site requirements. Consideration should also be
given to the function and aesthetics of both the recipient
and donor sites. There are now a myriad of free flap
options for dorsal hand coverage, and ultimately the
choice of flap is determined by both patient donor site
characteristics and surgeon preference. The following
should be evaluated in the recipient site: dimensions,
the color and texture of the tissues surrounding the
defect, structures needing reconstruction, available
recipient vessels, level of contamination, and the need
to restore sensation. Following radical débridement the
wound is often much larger and deeper than antici­
pated, and the microvascular anastomosis must be
placed well out of the zone of injury. It is therefore
desirable to choose a flap with a large and reliable cuta­
neous territory and a long pedicle of large caliber,
enabling anastomosis out of fields of trauma, thus
reducing the risk of vessel spasm and thrombosis at the
anastomosis. Available flaps include lateral arm flap,
scapula/parascapular flap, anterolateral thigh flap, tho­
racodorsal artery perforator flap, etc.10,17
Fasciocutaneous flaps provide excellent coverage for
dorsal hand defects and provide an excellent gliding
surface for tendons and joints in the hand. The ability
to easily and quickly reelevate fasciocutaneous flaps is
a definitive advantage when staged reconstruction of
bone, nerve, or tendon is anticipated under the flap.
Lateral Arm Flap
The lateral arm flap is excellent for providing thin cover­
age for small to medium defects of the hand. It can be
harvested as a composite flap, incorporating a segment
of up to 10 cm in length of the humerus or a segment
of vascularized triceps tendon for extensor tendon
reconstruction (Figure 35-6).
The flap is located on the lateral aspect of the upper
arm, centered on a line drawn from the insertion of the
deltoid to the lateral epicondyle, and spans the distal
half of the lateral arm and the proximal third of the
dorsolateral forearm. The pedicle is the posterior radial
collateral artery and venae comitantes, which is 0.75 to
2.0 mm in diameter and varies from 6 to 8 cm in length
(see Figure 35-6).
The flap can be designed with a 6- to 8-cm width,
which allows primary closure of the wound. If the width
is larger, the donor site requires skin grafting. It can also
be harvested as a pure fascial flap with split-thickness
skin grafting, which provides excellent coverage of
exposed extensor tendons when ultra-thin flap coverage
is required (Figure 35-7). This flap also can be designed
as a sensate flap based on the antebrachial cutaneous

380
Section 4:  Extensor Tendon Repair and Reconstruction
10 cm. The flap may be harvested in the suprafascial
or subfascial plane. There is a reduced incidence of
muscle herniation with suprafascial dissection, although
a 5-cm radius cuff of deep fascia should be preserved
around the perforator. A sensate flap can be achieved by
incorporating the lateral femoral cutaneous nerve (see
Figure 35-8 and Figure 35-9).
Other options for dorsal hand coverage also include
muscle flaps. Keep in mind that we prefer to use skin
flaps for dorsal hand coverage in the event that second­
ary reconstruction or revisions are required in the form
of tenolysis. If tenolysis is anticipated in the future, or
capsulotomy, it is much easier to reelevate a fasciocuta­
neous flap rather than a muscle flap, although muscle
flaps will atrophy very nicely and provide excellent
cosmesis and coverage. This is preferentially reserved
for patients that do not have any extensor tendon loss
or defects and have simply only exposed extensor
tendons.
Adipofascial flaps, such as the temporoparietal fascial
flap, are also a viable option for extensor tendon recon­
struction. We prefer to use an ALT adipofascial flap or
an ALT flap as opposed to a temporoparietal flap due to
Figure 35-7  A, Contracture of the dorsum of the left hand in a 50-year-old male patient due to extensive burn. B, Defect
size following resection of burn scar, tenolysis, and MCP joint capsulotomies. C, Lateral arm flap skin paddle design based on
size and geometry of defect template. D, Flap inset following microanastomosis of posterior radial collateral artery end-to-side
to radial artery and vena comitans end-to-end to dorsal vein.
A
B
C
D
ease of dissection, large flap size potential, and minimal
donor site morbidity.
SECONDARY PROCEDURES
Secondary procedures may be required following the
initial flap coverage, and these may involve, for example,
flap debulking, tenolysis, capsulotomy, tendon grafting
following Hunter rod removal, etc. One major advan­
tage of using a fasciocutaneous flap for extensor tendon
coverage is the ability to easily reelevate the flap at a
later stage for tenolysis or other procedures. This can
even be performed under local anesthesia using a “wide-
awake” approach to better judge the effects of surgery.
If the flap requires debulking we prefer to wait at least
3 months postoperatively before performing liposuc­
tion. Peripheral incisions and excess skin removal are
performed an additional 3 months later to ensure ade­
quate vascularity.
SUMMARY
Soft tissue coverage of extensor tendons in the hand
and digits that have either been primarily repaired or
grafted is of paramount importance to promote proper

381
Chapter 35:  Soft Tissue Coverage for Extensor Tendon Reconstruction
Figure 35-8  A, Extensive degloving injury, following a motor vehicle accident, of the dorsal right hand, with bone, extensor
tendon, and soft tissue defects. Note complete loss of EDC tendons on the dorsum of the distal forearm and hand. B, A
fasciocutaneous ATL flap was selected for coverage instead of a muscle flap in anticipation for future secondary surgeries and
need to reelevate the flap. C, ALT flap harvest with extension of fascia lata showing well vascularized tissue. D, Long extensor
tendon grafts harvested from the leg for primary extensor tendon reconstruction. E, Flap coverage after tendon grafting to
reconstruct the EDC tendons.
A
B
C
D
E

382
Section 4:  Extensor Tendon Repair and Reconstruction
gliding, minimize adhesion, and maximize function.
The reconstructive surgeon needs to have a wide arma­
mentarium of flap options for exposed extensor tendon
coverage. Any extensor tendon devoid of adequate soft
tissue will be at high risk for delayed wound healing,
tendon desiccation, contracture, stiffness, and potential
loss of hand function. The combination of adequate
débridement and well-vascularized coverage will allow
patients to start early active range of motion and reha­
bilitation to maximize function. Significant defects
often require more intricate reconstructions to maxi­
mize function. Therefore surgeons should not hesitate
to use a more direct “reconstructive elevator” approach
to provide the best outcome.
References
1. Foucher G, Braun JB: A new island flap transfer from the
dorsum of the index to the thumb, Plast Reconstr Surg 63:344–
349, 1979.
2. Earley MJ, Milner RH: Dorsal metacarpal flaps, Br J Plast Surg
40:333–341, 1987.
3. Dautel G, Merle M: Dorsal metacarpal reverse flaps. Anatomi­
cal basis and clinical application, J Hand Surg (Br) 16:400–
405, 1991.
4. Dautel G, Merle M: Direct and reverse dorsal metacarpal flaps,
Br J Plast Surg 45:123–130, 1992.
5. Quaba AA, Davison PM: The distally-based dorsal hand flap,
Br J Plast Surg 43:28–39, 1990.
6. Karacalar A, Akin S, Ozcan M: The second dorsal metacarpal
artery flap with double pivot points, Br J Plast Surg 49:97–102,
1996.
7. Yang D, Morris SF: Vascular basis of dorsal digital and meta­
carpal skin flaps, J Hand Surg (Am) 26:142–146, 2001.
8. Lutz BS, Wei FC, Chang SC, et al: Donor site morbidity after
suprafascial elevation of the radial forearm flap: A prospective
study in 95 consecutive cases, Plast Reconstr Surg 103:132–
137, 1999.
9. Becker C, Gilbert A: The cubital flap, Ann Chir Main 7:136–
142, 1988.
10. Wei FC, Jain V, Celik N, et al: Have we found an ideal soft-
tissue flap? An experience with 672 anterolateral thigh flaps,
Plast Reconstr Surg 109:2219–2226, 2002.
11. Angrigiani C, Grilli D, Siebert J: Latissimus dorsi musculocu­
taneous flap without muscle, Plast Reconstr Surg 96:1608–
1614, 1995.
12. Kim JT: Latissimus dorsi perforator flap, Clin Plast Surg
30:403–431, 2003.
13. Kim JT: Two options for perforator flaps in the flank donor
site: latissimus dorsi and thoracodorsal perforator flaps, Plast
Reconstr Surg 115:755–763, 2005.
14. Scheker LR, Langley SJ, Martin DL, et al: Primary extensor
tendon reconstruction in dorsal hand defects requiring free
flaps, J Hand Surg (Br) 18:568–575, 1993.
15. Sundine M, Shecker LR: A comparison of immediate and
staged reconstruction of the dorsum of the hand, J Hand Surg
(Br) 21:216–221, 1996.
16. Harpf C, Papp C, Ninkovic´ M, et al: The lateral arm flap:
review of 72 cases and technical refinements, J Reconstr Micro­
surg 14:39–48, 1998.
17. Gosain AK, Matloub HS, Yousif NJ, et al: The composite
lateral arm free flap: vascular relationship to triceps tendon
and muscle, Ann Plast Surg 29:496–507, 1992.
Figure 35-9  A, Hand motion and cosmetics 6 months postoperatively following coverage of a dorsal hand with an ATL flap,
which is in the case shown in Figure 35-8. B, Flap appearance after liposuction performed 3 months postoperatively.
A
B

383
CHAPTER
36 
TREATMENT OF BOUTONNIÈRE
AND SWAN-NECK
DEFORMITIES
Fraser J. Leversedge, MD, and Felicity G.L. Fishman, MD
The boutonnière and swan-neck deformities of the
digits are differentiated as being the sequelae of trauma,
or as a part of the spectrum of rheumatoid disease.
POST-TRAUMATIC DEFORMITY
Post-Traumatic Boutonnière Deformity
Post-traumatic boutonnière (or “buttonhole”) deformi­
ties, characterized by hyperextension of the meta­
carpophalangeal (MCP) joint, flexion of the proximal
interphalangeal (PIP) joint, and hyperextension of the
distal interphalangeal (DIP) joint, are caused by disrup­
tion of the central slip. Attenuation of the triangular
ligament allows the lateral bands to migrate volar to the
PIP joint axis of rotation, transforming the lateral bands
into a flexion force at the PIP joint and extension force
at the DIP joint (Figure 36-1).
Traumatic injuries to the central slip can be divided
into two groups: (1) Closed injuries: Typically, avulsion
of the central slip from its insertion occurs due to a
hyperflexion injury or volar dislocation of the PIP joint.
An associated avulsion fracture from the dorsal base of
the middle phalanx may be present. (2) Open injuries:
Lacerations to the dorsal digit can disrupt the central
slip directly.
Often, patients present with complaints of “jamming”
or spraining the affected digit and the clinician should
be suspicious of a central slip injury particularly in the
presence of localized swelling, ecchymosis, and/or ten­
derness to the dorsal PIP joint and a loss of full active
PIP joint extension; a lack of motion should not be
disregarded as a consequence of swelling or pain. Early
diagnosis may be complicated by the delayed develop­
ment of the deformity, often 2 to 3 weeks following
initial injury.
Physical examination findings supportive of an acute
central slip injury include: (1) A 15° to 20° extension
lag at the PIP joint with the wrist and MCP joint held
in full flexion.1 (2) Absence or weakness of resisted
active extension of the PIP joint with the PIP joint
OUTLINE
The treatment of boutonnière and swan-neck deformi­
ties of the digits is guided by the etiology and staging
of the condition, primarily differentiated as being the
sequelae of trauma or as a part of the spectrum of
rheumatoid disease. A thorough evaluation should
include consideration for the current or potential
pathology of adjacent joints, the active and passive
motion of involved joints, subjective concerns for pain
or instability, and radiographic assessment. Careful
assessment of the deformity is critical to the decision
on an appropriate and individualized treatment strat­
egy. The primary goals of treatment of boutonnière
and swan-neck deformities are to alleviate pain and
to improve function. Treatment ranges from splinting
and therapy to operative intervention. The surgical
procedures include ligament repair or reconstruction
and tenodesis or arthrodesis. Long-standing and severe
deformities are difficult to correct and consequently
full function of the digits may not be achieved. Patient
selection is critical to achieving successful surgical
outcomes.
The intricate and coordinated functions of the hand and
digits rely extensively on the complex but balanced
interactions between the extrinsic and intrinsic muscu­
lature of the hand. Alterations in the relationships
between these extrinsic and intrinsic systems due to
trauma or secondary to the effects of systemic disease
may cause the development of functional deformities
such as a boutonnière or swan-neck deformity. Such
changes may be acute or chronic in nature. Treatment
for these conditions should be guided by a comprehen­
sive evaluation of the patient, a consideration for associ­
ated injuries or structural deficiencies, the timing of
injury, and the severity of the deformity. Importantly, a
functional assessment and recognition of the patient’s
activity requirements and expectations are critical for
creating a plan of care.

384
Section 4:  Extensor Tendon Repair and Reconstruction
Post-Traumatic Swan-Neck Deformity
Post-traumatic swan-neck deformity is characterized by
the inability of the terminal slip to extend the DIP joint
combined with laxity of the PIP volar plate resulting in
hyperextension of the PIP joint and flexion of the DIP
joint. Attenuation of the transverse retinacular ligament
coupled with hyperextension of the PIP joint leads to
dorsal migration of the lateral bands in relation to the
PIP joint axis of rotation, thereby exerting an extension
force on the PIP joint and a flexion force on the DIP
joint.
Laxity or incompetence of the volar plate can be
caused by dorsal dislocation of the PIP joint. Recurrent
injury may lead to chronic dorsal instability of the PIP
joint. Conversely, terminal tendon avulsion from its
insertion at the base of the distal phalanx may cause an
imbalance in the extensor mechanism, resulting in
hyperextension of the PIP joint.
Patients may present with a history of acute injury
or recurrent dorsal PIP hyperextension injuries cul­
minating in progressive subluxation or dislocations,
often unrecognized. Patients presenting with a chronic
“mallet” deformity should arouse suspicion for PIP
hypermobility. On physical examination, the affected
digit will exhibit PIP joint hyperextension and DIP joint
flexion posturing, often with MCP joint flexion. For
patients with flexible PIP and DIP joint deformities,
active and passive motion of the PIP joint should be
assessed and a Bunnell’s intrinsic tightness test should
be performed.
Bunnell’s intrinsic tightness test: Increased resistance to
passive PIP joint flexion with the MCP joint in extension
compared with flexion indicates a relative shortening of
the intrinsic muscle–tendon units.
The post-traumatic swan-neck deformity may prog­
ress through four characteristic stages7:
1. Full passive PIP joint range of motion
2. Intrinsic tightness secondary to prolonged hyper­
extension of the PIP joint
3. Fixed hyperextension of the PIP joint regardless of
MCP position due to attenuation and contraction
of the transverse retinacular ligament and dorsal
subluxation of the lateral bands
4. Articular degeneration and fixed hyperextension
deformity of the PIP joint
RHEUMATOID DEFORMITY
Rheumatoid Boutonnière Deformity
of the Fingers
Rheumatoid boutonnière deformities occur due to pro­
gressive erosion of the central slip, transverse retinacular
ligaments, and the triangular ligament by the destructive
synovitis characteristic of rheumatoid arthritis. As the
restraints provided by triangular ligament are lost, the
lateral bands migrate in a volar direction, transforming
starting in 90° of flexion.2,3 (3) Elson test: The patient
attempts to extend actively the PIP joint of the involved
finger against resistance from a 90° starting position
over the edge of a table. The absence of extension force
at the PIP joint accompanied by fixed extension of the
DIP joint confirm disruption of the central slip as exten­
sion forces are being transferred to the DIP joint by the
lateral bands.4,5 (4) Boyes test: A positive test may be
found in progressive stages of boutonnière deformity
but is not reliable for the diagnosis of acute central slip
injuries.5 Loss of active flexion of the DIP joint with the
PIP joint held in passive extension due to tension across
the lateral bands following disruption of the central
slip. Active flexion of the DIP is possible with the PIP
joint flexed.
After a traumatic injury to the central slip, the bou­
tonnière deformity generally progresses through five
stages6:
1. Disruption of the central slip results in resting
flexion of the PIP joint and weak extension of the
middle phalanx via the lateral bands
2. Absent active PIP joint extension combined with
attenuation of the triangular ligament and con­
tracture of the transverse retinacular ligaments
results in the volar migration of the lateral bands
3. Extension forces are transmitted through the
lateral bands, causing hyperextension at the DIP
joint
4. Progressive contracture of the PIP joint volar plate
and the oblique retinacular ligament causes fixed
flexion contracture at the PIP joint
5. Progressive articular degeneration occurs after pro­
longed and untreated pathology
Figure 36-1  Lateral view of the digit demonstrating the
volar subluxation of the lateral bands (clb) in a simulated
boutonniere deformity (central slip [CS]). (Reprinted with
permission: © 2004 Leversedge FJ, Goldfarb CA, Boyer MI.)
CS
clb

385
Chapter 36:  Treatment of Boutonnière and Swan-Neck Deformities
 Type III—Decreased PIP joint motion in all posi­
tions of MCP joint flexion and extension
 Type IV—Fixed extension contracture of the PIP
joint with degeneration of PIP joint articular
cartilage
Rheumatoid Thumb Deformity
Thumb deformity associated with rheumatoid disease
may be classified based on changes specific to the car­
pometacarpal (CMC), MCP, and interphalangeal (IP)
joints, as outlined by a modified classification system of
six types initially proposed by Nalebuff.9,10
The most common rheumatoid thumb deformity is
the type I (boutonnière) deformity. This is characterized
by IP joint hyperextension and MCP joint flexion
without primary involvement of the CMC joint. Typi­
cally, the type I deformity begins with proliferative syno­
vitis within the MCP joint, which leads to attenuation
of the extensor pollicis brevis (EPB) tendon insertion
and expansion of the extensor hood. Concurrently, the
collateral ligaments become attenuated and the exten­
sor pollicis longus (EPL) is displaced ulnar and volar to
the MCP joint axis of rotation. Subsequently, the proxi­
mal phalanx becomes subluxed palmarly relative to the
metacarpal head and the altered pull of the intrinsics
and the EPL leads to IP joint hyperextension and MCP
joint flexion. Radial abduction of the thumb metacarpal
can occur in compensation for MCP joint flexion. Type
I deformities are further divided into stages: (1) stage I,
or mild: PIP joint synovitis and mild fully correctable
extensor lag; (2) stage II, or moderate: marked flexion
deformity of PIP joint, flexible or fixed; and (3) stage
III, or severe: PIP articular destruction.
The second most common rheumatoid thumb defor­
mity is the type III (swan-neck) deformity (Figure
36-2).9,11 CMC joint synovitis leads to erosion of the
articular surface and capsular attenuation, which con­
tributes to the dorsal and radial subluxation of the CMC
joint. An adduction contracture of the metacarpal devel­
ops due to the alteration in forces across the CMC joint
with daily activities such as pinch and grasp. Compensa­
tory MCP joint hyperextension and IP joint flexion,
characteristic of a type III swan-neck deformity, is poten­
tiated as functional compensation for the progressive
adduction contracture.12
METHODS OF TREATMENT
Post-Traumatic Boutonnière Deformity
Nonoperative Management
Generally, non-surgical management is indicated for
closed injuries within 8 to 12 weeks from the time of
injury. This treatment is appropriate when the anatomi­
cal length relationship between the central slip and the
lateral bands is restored after correction of the defor­
mity. Nonoperative treatment can also be attempted in
them into a flexion force at the PIP joint. The continued
flexion deformity of the PIP joint results in contractures
of the oblique retinacular ligament, the volar plate, and
the collateral ligaments; progression from a flexible to
a fixed deformity of the PIP joint occurs with time. The
classic boutonnière deformity involves flexion of the
PIP joint and hyperextension of the DIP and MCP joints
and evolves through three stages.8 Stage I is considered
a mild, involving PIP joint synovitis and a passively cor­
rectable flexion deformity of the PIP joint. Stage II, or a
moderate deformity, involves a flexion contracture of
the PIP joint and concomitant MCP joint hyperexten­
sion. Stage III involves a fixed contracture of the PIP
joint and destruction of the articular surfaces.
Rheumatoid Swan-Neck Deformity
of the Fingers
Swan-neck deformities associated with rheumatoid
disease are characterized by hyperextension of the PIP
joint and concurrent MCP and DIP flexion deformities.
A swan-neck deformity may be caused by primary
pathology affecting the MCP, the PIP, or the DIP joint.7
 MCP joint pathology: The characteristic rheumatoid
digital deformity of flexion and ulnar drift leads
to imbalance of the extensor mechanism. The PIP
is hyperextended by the extension force exerted
across the PIP by the dorsal shift of the lateral
bands. The MCP joint component of a swan neck
deformity is flexion, which can be secondary to
chronic synovitis with degeneration of the sagittal
bands, intrinsic tightness, and/or articular destruc­
tion resulting in volar subluxation of the MCP
joint.
 PIP joint pathology: The volar plate of the PIP joint,
the collateral ligaments, and the insertion of the
flexor digitorum superficialis (FDS) tendon can
become attenuated in rheumatoid disease, result­
ing in PIP hyperextension. Also, progressive atten­
uation of the transverse retinacular ligaments
results in a loss of the normal restraints to the
dorsal migration of the lateral bands, leading to
PIP joint hyperextension.
 DIP joint pathology: Synovitis of the DIP joint may
cause attenuation and eventual rupture of the ter­
minal extensor tendon. Subsequently, the extensor
forces are concentrated at the PIP joint, resulting
in a hyperextension deformity of the PIP joint.
Nalebuff classified rheumatoid swan-neck deformities
into four distinct types7:
 Type I—Fully mobile and flexible PIP joint, regard­
less of MCP joint position
 Type II—Active and passive PIP joint motion is
limited with MCP joint held in extension due to
intrinsic tightness

386
Section 4:  Extensor Tendon Repair and Reconstruction
considered. As PIP joint flexion and grip strength are
compromised rarely with a boutonnière deformity, the
surgeon should avoid trading active digital flexion for
improved extension.
Post-Traumatic Swan-Neck Deformity
Nonoperative Management
Although nonoperative treatment is rarely effective in
treating post-traumatic swan-neck deformities, a small
subset of patients with flexible deformities who are
capable of actively initiating PIP joint flexion may
benefit from a trial of figure-of-eight ring splinting to
maintain the lateral bands in their anatomical position
and to prevent PIP joint hyperextension (Figure 36-3).
the cases with a volar dislocation or central slip avulsion
fracture if the PIP joint is stable and acceptable joint and
fracture reductions are achieved.
PIP joint extension splinting is applied when full
passive extension and congruent reduction of the PIP
joint is maintained. Supplemental transarticular Kirsch­
ner wire fixation can be considered. If a flexion contrac­
ture of the PIP joint is present, progressive static splinting
or serial casting, or dynamic extension splinting is uti­
lized in the attempt to restore a supple joint.
The splinting is maintained at all times for 6 to 8
weeks to completely immobilize the PIP joint. After this
period, following reevaluation to confirm stable reduc­
tion, the patient is transitioned to buddy straps during
the day and night-time extension splinting for an addi­
tional 4 to 6 weeks. Throughout the duration of the PIP
joint splinting, the patient is instructed for active and
passive DIP joint range of motion exercises.
Operative Management
Surgical intervention should be considered for patients
who have failed 3 months of conservative treatment,
such as extension splinting, and for open injuries or
patients with fixed deformity and associated degenera­
tive joint changes. Full passive extension of the PIP joint
should be sought prior to surgical reconstruction.
Burton and Melchior emphasized that boutonnière
reconstructions are generally more successful in patients
with flexible joints and that a first-stage joint contrac­
ture release, followed by an exercise and splinting
program, can sometimes obviate the need for further
procedures.13 If arthritic changes are present, a soft tissue
reconstruction may not yield a satisfactory outcome
and, therefore, PIP joint reconstruction with arthrodesis
or arthroplasty with extensor reconstruction should be
Figure 36-3  A figure-of-eight ring splint (Silver Ring Splint;
Charlottesville, VA) used to prevent PIP joint hyperextension
in a mild, flexible swan-neck deformity. (Reprinted with
permission: © 2004 Leversedge FJ, Goldfarb CA, Boyer MI.)
Figure 36-2  A, Palmar and lateral clinical photograph of a swan-neck deformity of the thumb; B, lateral radiograph of
the thumb demonstrating a swan-neck deformity involving CMC joint subluxation, metacarpal adduction contracture,
hyperextension of the MCP joint, and thumb IP joint flexion. (Reprinted with permission: © 2004 Leversedge FJ, Goldfarb CA,
Boyer MI.)
A
B