Correction of The Claw Hand
Correction of The Claw Hand
Correction of The Claw Hand
Claw Hand
Anthony Sapienza, MDa,*, Steven Green, MDb
KEYWORDS
Intrinsic paralysis Claw hand Tendon transfers
Capsulodesis
Intrinsic paralysis can be the manifestation of plate, spasticity or contracture of the intrinsic
a variety of pathologic entities such as stroke, muscles, intrinsic tendon adhesions at the level
cerebral palsy, Charcot-Marie-Tooth, muscular of the MCP joint, fascial or skin contractures (eg,
dystrophy, leprosy, trauma, cervical disease, and burns, scarring, Dupuytren disease). The observa-
compressive and metabolic neuropathies. tion of such rare cases had initially led Zancolli to
Patients may present with a spectrum of clinical propose his capsulodesis in the treatment of
findings dependent on the cause and severity of claw deformity.4
the disease. The 3 main problems caused by Patients may initially present with subtle findings
intrinsic weakness of the fingers are clawing with such as weakness of pinch or an abducted
loss of synchronistic finger flexion, inability to posture of the small finger. A palsied first dorsal in-
abduct and adduct the digits, and weakness of terosseous muscle affects thumb–index finger
grip. Smith1 in 1987 estimated that the intrinsic pinch, and stabilization of the index finger is
musculature contributes up to 60% to grip usually accomplished by bracing it against the
strength. Kozin2 in 1999 simulated low median or middle finger. On some occasions a patient
low ulnar nerve lesions in healthy individuals via requires surgery to restore index finger abduction,
nerve blocks and determined that the average especially when considering transfers to restore
decrease in grip strength was 38% after ulnar thumb-index pinch (see Lee and Wisser elsewhere
nerve block and 32% after median nerve block. in this issue for further exploration of this topic).
Clawing is defined as hyperextension of the meta- Pinch may also be affected by weakness of the
carpophalangeal (MCP) joints and flexion of the adductor pollicis. In these cases, acute flexion of
interphalangeal (IP) joints (Figs. 1 and 2). The the IP joint via the flexor pollicis longus allows
Zancolli classification3 distinguishes between the extensor pollicis longus to exert an adduction
intrinsic paralysis with and without claws. Intrinsic moment on the thumb because the IP extensor
paralysis without claw can occur when the ex- action is blocked (Froment sign,5 Fig. 3). The
trinsic muscles are also paralyzed (as seen in thumb MCP joint may hyperextend during pinch
high ulnar nerve palsy involving the flexor digito- (Jeanne sign6) if there is thumb volar plate laxity
rum profundus (FDP) to the ring and small fingers) and both heads of the flexor pollicis brevis are
or conservation of the activity of the corresponding paralyzed.
finger lumbrical (as seen with the median nerve Chronic abduction of the small finger results
innervated lumbricals of the index and middle from the inability of the palsied third palmar
fingers in ulnar nerve palsy). There may be other interossei to counteract the force of the extensor
rarer causes, which prevent hyperextension of digiti quinti (EDQ). This extrinsic extensor to the
the MCP joint: congenital shortness of the volar small finger exerts an MCP joint extension force
a
Hand Surgery Division, Department of Orthopedics, Bellevue Hospital Center, NYU Hospital for Joint
Diseases, 301 East 17th Street, New York, NY 10003, USA
b
2 East 88th Street, New York, NY 10128, USA
* Corresponding author.
E-mail address: anthony.sapienza@nyumc.org
The motor end plates die off by around 18 months, extended and are therefore indicated only if the
so even in the presence of an improving neurologic Bouvier test is positive. These procedures include
condition, the likelihood that the intrinsics will MCP joint arthrodesis, bone block,15,16 tenodeses,
be reinnervated in a timely fashion must be and volar plate capsulodesis. MCP joint arthrod-
determined. esis of the fingers is rarely performed to prevent
clawing because there are other static procedures
that can inhibit hyperextension and still permit joint
SURGICAL TREATMENT OPTIONS flexion.
Surgical treatment of a claw hand can involve
Capsulodesis
either static or dynamic procedures. The appro-
priate choice of procedure should take into In the original Zancolli capsulodesis4 procedure,
account the patient’s complaints, goals, and the volar capsule of the MCP joint is approached
ability to comply with a rehabilitation program. through a longitudinal incision centered over the
Static procedures have the advantage of being A1 pulley of each involved digit. We recommend
simple and do not require significant postoperative using a transverse incision to improve visualization
therapy. The disadvantage of a static procedure is when more than 1 finger requires treatment. The
that it cannot correct weakness. Static procedures A1 pulley is incised (like a trigger finger release)
are designed to prevent MCP joint hyperextension and the flexor tendons reflected laterally to expose
or flex the MCP joint so that the IP joints can be the origin of the volar plate on the metacarpal neck
(Fig. 10).
In Zancolli’s original description the volar plate is
then sharply incised and advanced proximally in
a “vest over pants” imbrication technique. Late
stretching of the capsulodesis and recurrence
of MCP joint hyperextension led to several modifi-
cations of the procedure. A more reliable
technique involves detaching the volar plate off
the metacarpal neck and advancing it proximally.
The volar plate is sharply released from its origin
Srinivasan tenodesis
Srinivasan21 described “the extensor diversion graft
operation” for correcting claw deformity and
reducing the disability of the intrinsic minus fingers
seen in leprosy. The procedure was designed to re-
balance the extrinsic extensor dominance at the
MCP joint to improve hyperextension and to allow
the PIP joints to remain moderately extended
when the extrinsic flexors exerted their action on
the fingers. Conceptually, this would allow a more
synchronous grasp by allowing the MCP joints to
flex with the IP joints instead of after as seen with
intrinsic palsy. The procedure inserted a free tendon
graft, which was attached to the extrinsic extensor
just proximal to the MCP joint, passed volar to the
transverse metacarpal ligament, and distally
attached to the lateral bands. The surgery had to
be performed under local anesthetic to set the
Fig. 12. Schematic Riordan tenodesis. One-half of
tension on the graft. One or 2 test stitches were in-
ECRL and one-half of ECU are used (A) and split into
serted and the patient was asked to extend the
a total of 4 tails. Each tail is then routed volar to the
deep transverse metacarpal ligament and attached
finger. If the claw deformity was undercorrected
to the lateral band (B). (Reprinted from Riordan DC. then the finger went into hyperextension at the
Tendon transplantations in median and ulnar-nerve MCP joint and flexion at the IP joint. If the deformity
paralysis. J Bone Joint Surg Am 1953;35:317; with was overcorrected then the finger assumed an
permission.) intrinsic-plus position, with deficient flexion at the
Correction of the Claw Hand 59
MCP joint and full extension at the IP joint. Although Dynamic Transfers
the concept of rebalancing the extensor apparatus
Dynamic tendon transfers involve transferring
was novel, and most cases did have a correction
functional muscle-tendon units to restore another
of their claw deformity, the investigator noted that
by transferring the working unit to a new location.
it was not possible to predict the functional effect
The transfer should involve sacrificing an expend-
of the operation on the intrinsic minus hand.
able muscle-tendon unit (eg, 1 wrist extensor
donor, extensor carpi radialis brevis [ECRB];
Smith sling tenodesis whereas 2 remain, ECRL and ECU) so that hand
Smith22 described a sling tenodesis in which a graft function remains balanced. Dynamic procedures
was passed around the deep transverse meta- have the disadvantage of being more complex
carpal ligament and sutured to the lateral bands than static procedures. The advantages of
of adjacent fingers. The lateral bands are ap- dynamic procedures involve correction of the
proached through midaxial incisions on the claw deformity, improving grip strength, restora-
opposing sides of the ring and small or middle tion of power pinch (see the article by Lee and
and index fingers. A tendon graft is passed proxi- Wisser elsewhere in this issue for further explora-
mally through one of the midaxial incisions and tion of this topic), and restoring the synchronistic
dorsal to the deep transverse metacarpal liga- flexion of the fingers. There have been 2 proposed
ment. A curved hemostat is then placed in the tendon transfer routes. The volar route involves
other digital incision to retrieve the graft so that it passing the tendon transfer through the carpal
loops around volar to the deep transverse meta- canal and volar to the deep transverse metacarpal
carpal ligament. The graft is sutured into one of ligaments. This technique has been described by
the lateral bands. The MCP joints are flexed to Brand23–25 using a wrist extensor and Bunnell26
30 , whereas the IP joints are extended and the using a flexor digitorum superficialis (FDS). Brand
graft is secured to the other lateral band while also described his transfer via a dorsal route that
under tension (Fig. 14). This tenodesis produced places the tendon transfer though the intermeta-
PIP joint extension as MCP joint extension carpal spaces, then volar to the deep transverse
occurred but did not have a significant impact on metacarpal ligaments and through the lumbrical
synchronous finger flexion and did not augment canals.
grip strength. There have been 4 described tendon insertion
sites (Fig. 15). Brand and Bunnell attached the
transferred tendon to the lateral band of the
extensor apparatus. Zancolli lassoed his tendon
transfer around the A1 pulley, and Omer27 modi-
fied the procedure to loop around the A2 pulley.
Burkhalter and Strait28 fixed the transferred
tendon to the proximal phalanx via bone tunnels
(Fig. 16).
In deciding which insertion site to use the
surgeon needs to revisit the Bouvier test. If the
Fig. 16. (A–C) 2.0-mm drill hole is used for both cortices, with the near cortex further enlarged with a 2.7-mm
drill. (Reprinted from Hastings H. Ulnar nerve paralysis. In: Strickland JW, Graham TJ, editors. Master techniques
in orthopaedic surgery: the hand. 2nd edition. Philadelphia: Lippincott Williams & Wilkins; 2005. p. 224; with
permission.)
Bouvier test is positive then by definition has the potential of inhibiting FDP gliding because
the extensor mechanism is competent to extend of the increased bulk within the sheath because the
the IP joints and the surgeon can consider insert- FDS tendon is folded back on itself at the level of
ing the tendon transfer into the pulleys of the the Camper chiasm. Another pitfall is that some
tendon sheath or directly into the bone of the prox- patients have significant joint laxity and have hy-
imal phalanx. The advantage of these insertion perextensible PIP joints. In these individuals, if
sites is that it is easier to set the tension of the the FDS tendon is released at its distal insertion
transfer. The usefulness of the bone tunnel inser- on the middle phalanx then the patient may
tion site can also be recognized because it has develop a swan-neck deformity from the unop-
the advantage of a strong bone-tendon interface. posed pull of the extrinsic extensors. In these indi-
If the Bouvier test is negative, then IP joint exten- viduals leaving a stump of the FDS at the level of
sion can be accomplished only if the tendon is the PIP joint allows it to scar down to the sheath
transferred into the lateral bands. and creates a tether to minimize hyperextension,
or the surgeon can suture the stump directly to
the sheath to ensure its tethering action.
FDS Transfers
Zancolli lasso Stiles-Bunnell transfer
The Zancolli17 lasso procedure creates a function- Stiles in 192231 was the first author to describe
ally dynamic tenodesis in which each FDS is a tendon transfer to the lateral bands to restore
divided at its insertion on the middle phalanx, intrinsic function. Bunnell modified the technique
looped around its corresponding A1 pulley, and by transferring all the FDS tendons to the lateral
sutured back onto itself to provide flexion of the bands of both sides of each clawed digit.26,32 He
MCP joints (Fig. 17). By definition this is a dynamic found that this transfer was too powerful and
transfer, but because it involves rerouting the inser- caused swan-neck deformities. Littler33 further
tion of a finger flexor, no change in grip strength modified the technique to use 1 FDS tendon to
occurs.29 This procedure is good for diffuse paral- motor 2 to 4 digits. Midaxial incisions on the radial
ysis or if limited donor tendons are available. The border of each digit are used to expose the lateral
procedure improves the appearance and function band and flexor sheath. A window in the A3 pulley
of a claw hand only if the Bouvier test is positive. is used to divide the middle or ring FDS tendon
A modification of the Zancolli lasso uses only distally. The tendon is then retrieved through
one-half of the FDS tendon of the middle finger.30 a midpalmar incision, split longitudinally into 2 to
Omer27 also modified the procedure to loop the 4 tails, and each tail is passed through the lumbr-
tendon around the A2 pulley. The Zancolli lasso ical canal volar to the deep metacarpal ligament
Correction of the Claw Hand 61
Fig. 17. The Zancolli lasso procedure: the FDS tendon is released from its insertion (B) and sutured back to itself
over the A1 pulley (A, C). (Reprinted from Tse R, Hentz VR, Yao J. Late reconstruction for ulnar nerve palsy. Hand
Clin 2007:23(3):383; with permission.)
and attached to the lateral bands (Figs. 18 and 19). Tension on the graft is set by using 50% of the
A strong muscle that was previously the prime available excursion with the wrist neutral, the
flexor of the PIP joint now becomes the prime MCP joints flexed to 60 , and IP joints extended.
extensor of that same joint and leaves the FDP After transfer into the lateral bands, the wrist
as the only digital flexor. The sublimus and profun- is splinted in neutral with MCP joints flexed
dus no longer act synergistically, and reeducation to 60 and IP joints extended for 1 month. If the
for them to act reciprocally can be difficult. Bouvier test is positive then the tendon can be
sutured into either the A2 pulley34 or inserted into
a bone tunnel on the radial aspect of the proximal
phalanx and tied over a button.28 If the transfer is
into the proximal phalanx or A2 pulley then the IP
joints are allowed to immediately mobilize,
whereas the wrist and MCP joints remain splinted
Fig. 18. Middle FDS split into 2 tails and passed down
the lumbrical canals of ring and small fingers. Fig. 19. FDS tendon transfer into the lateral bands.
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