Phẫu Thuật Tạo Hình Grabb & Smith’s (Bản Cập Nhật – Kevin C. Chung)

ECRL to FPL
Flexor carpi ulnaris split to flexor carpi radialis and flexor carpi ulnaris for wrist balance
Transfer of the PL tendon with an extension of palmar aponeurosis, also known as a Camitz transfer, is
often utilized in patients with severe carpal tunnel syndrome and advanced thenar atrophy. 28 The
primary advantages of this transfer are its ease of harvest, as it lies in the same surgical field as a carpal
tunnel release, and the lack of functional deficit. However, the tendon may be damaged in traumatic
median nerve palsy owing to its superficial location; it is a weak muscle; and its vector of pull is not ideal
for producing true opposition. It is, however, useful in providing palmar abduction in patients with
severe thenar atrophy to aid in grasp.
The FDS opponensplasty was originally described in 1938 by Royle. 29 This transfer typically involves
dividing the ring finger FDS tendon distally—in part or whole—and retrieving it through the carpal
tunnel before rerouting it to the APB insertion. The original description, which passed the tendon
through the sheath of the FPL was later modified by Bunnell, who proposed rerouting the tendon
through a pulley created by a strip of FCU tendon to improve its vector of pull. 30 Thompson later
advocated tunneling the tendon subcutaneously to reach the thumb. 31 The primary disadvantage of the
FDS opponensplasty is that it can only be used when the median nerve injury has occurred distal to the
innervation 
 of the FDS.
The abductor digiti minimi (ADM) can be transferred from the hypothenar musculature, providing an
excellent vector for opposition and restoring muscular bulk to the thenar eminence (Figure 79.3). This
transfer is synergistic to opposition and provides good strength and excursion but has limited ability to
produce palmar abduction. This technique, known as the Huber transfer, has been relegated mostly to
children with hypoplastic thumb deformity or when other options are not available. The ADM muscle
belly provides improved cosmetic appearance of the thenar region in children with hypoplastic thumb
deformity, which is one benefit despite its functional limitations.
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FIGURE 79.3 Huber transfer. The abductor digiti minimi muscle is isolated on its neurovascular pedicle and freed from its
attachments to the pisiform and the hypothenar eminence. It is rotated across the palm and tunneled subcutaneously to the
abductor tubercle or abductor pollicis brevis tendon.
Lastly, the EIP opponensplasty is an excellent option that can be used in high or low median nerve palsy
and, when routed around the ulnar aspect of the wrist, provides an ideal vector for opposition (Figure
79.4). Although the EIP is not a strong muscle, it is sufficient to position the thumb in opposition. This
transfer is advantageous due to its ease of harvest, availability in high and low palsies, and minimal
functional deficit. In high median nerve palsy, the EIP transfer is most commonly used.
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FIGURE 79.4 Extensor indicis proprius (EIP) opponensplasty. A,B. Incision markings for harvest of EIP tendon and
tenorrhaphy site at the abductor pollicis brevis tendon. C. EIP tendon is divided over the metacarpophalangeal joint. D. EIP is
routed subcutaneously around the ulnar border of the hand. E. Planned path of the tendon transfer (note the position of the
pisiform marked with dotted line). F. Tendon passed subcutaneously to the abductor pollicis brevis tendon using a curved
tendon passer. G. EIP tendon transferred to the APB to hold the thumb in abduction (photograph of different patient).
With high median nerve palsy, all of the musculature of the forearm flexor compartment, with the
exception of the ulnar-innervated FCU and FDP to the ring and small fingers, are paralyzed. Therefore,
many of the workhorse muscles for tendon transfer (i.e., FDS, FCR, PL) are unavailable. Only the EIP
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opponensplasty and Huber transfer are available, and the EIP is typically selected. In addition to
restoring opposition, these patients must also regain flexion of the index and long fingers as well as the IP
joint of the thumb. In our experience, FDP function to the long finger is often preserved, although may be
weak, presumably due to cross-innervation by the ulnar nerve. The only muscles remaining for restoring
these functions are the ECU, BR, and ECRL. Some reports of ECU harvest have demonstrated radial
deviation wrist deformities in these patients and severe grip weakness. 32 Therefore, the BR is typically
selected to restore FPL function, and the ECRL is used for index finger flexion when needed. In most
instances, however, adequate index and long finger flexion can be achieved with a side-to-side transfer to
the functioning ring and small finger profundus tendons.
The lack of forearm pronation resulting from denervation of the PT and pronator quadratus does not
always require treatment, as shoulder abduction can position the forearm in a pronated position. If this
deficit is a problem, or if shoulder function is abnormal, a biceps rerouting can be performed, which
converts the biceps from a supinator into a pronator. 33
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Ulnar Nerve Palsy
Anatomy
Unlike the median and radial nerves, the ulnar nerve has very few motor branches proximal to the hand,
innervating only the FCU and the FDP muscles to the ring and small fingers in the proximal forearm.
Approximately 7 to 8 cm proximal to the wrist, the ulnar nerve gives off the dorsal sensory branch,
providing cutaneous innervation to the dorsal and ulnar hand. The ulnar nerve continues through the
Guyon canal at the volar-ulnar wrist, where it again branches into sensory and motor components. At this
level, the ulnar nerve provides motor innervation to the hypothenar muscles, palmaris brevis, all of the
interosseous muscles, the lumbricals to the small and ring fingers, and the adductor pollicis.
Approximately 80% of the time, the ulnar nerve also innervates the deep head of the FPB. Notably,
anomalous innervation patterns (i.e., Martin-Gruber and Riche-Cannieu) are not uncommon, and clinical
presentations may vary in these patients. 34,35 In such cases, electromyography may be useful to help
determine which muscles are available for transfer.
The ulnar nerve is tremendously important to hand function, and a number of clinical manifestations are
seen with ulnar nerve palsies (Table 79.4). With resisted pinch, weakness of the first dorsal interosseous
muscle and adductor pollicis (AP) will result in thumb IP joint flexion as the FPL attempts to substitute
for a weak pinch, known as Froment sign. Intrinsic function can also be evaluated by asking the patient to
abduct and adduct the fingers, to cross their index and middle fingers, or to perform the Pitres-Testut test
—placing the hand flat on a table with the fingers fully abducted and moving the long finger side to side.
The small finger may be abnormally abducted, a finding known as Wartenberg sign, which results from
third volar interosseous weakness and the unopposed pull of the EDQ muscle.
TABLE 79.4
Dynamic Tendon Transfers for Claw Deformity Caused by Ulnar Nerve Palsy
Technique
Description
Comments
Dynamic tenodesis
Wrist
tenodesis
(Fowler and
Tsuge)
Free tendon graft attached to central extensor retinaculum and passed
from dorsal to palmar, deep to deep transverse metacarpal ligaments
(DTMLs) and inserted into lateral bands
Tenodesis loosens with time
Extrinsic finger
flexors
Flexor
digitorum
superficialis
(modified
Stiles-
Bunnell)
Long finger flexor digitorum superficialis split into four slips, routed
through lumbrical canal of each finger volar to the DTMLs, sutured to
the lateral band of the extensor apparatus
Insertions
sites
modified
several times:
Lateral
bands
(Stiles,Bunnell)
Phalangeal
insertion
(Burkhalter)
Pulley
insertion
(Riordan, Zancolli)
Interosseous insertion
(Zancolli, Palande)
PIP extensor lag can occur in
donor finger
Finger-level
extensors
Extensor
indicis
proprius and
extensor
digiti minimi
Extensor indicis proprius and extensor digiti minimi tendons are
transferred to lateral bands
May
produce
excessive
tension
in
extensor
mechanism
(intrinsic-plus
deformity)
and
reverse
metacarpal arch
Does not add grip strength
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(Fowler)
Wrist-level motor
transfers
Dorsal route
extensor
carpi radialis
brevis
(Brand)
Extensor carpi radialis brevis lengthened by free tendon graft (split into
four tails); passed through intermetacarpal spaces, deep to DTMLs, and
attached to radial lateral bands long finger, ring finger, small finger, and
ulnar lateral band of index finger
Uses free tendons for length
(adhesions)
Does
not
improve
metacarpal
arch
or
grip
strength
Extensor
carpi
radialis
longus (ECRL) can also be
used
Flexor
carpi
radialis
(FCR)
(Riordan)
FCR is augmented with free tendon graft brought dorsally around the
forearm and then routed in similar fashion to dorsal Brand transfer
Removes FCR, which is a
strong wrist flexor
Flexor route
ECRL
(Brand)
Free tendon graft is passed through the carpal tunnel (split into four
tails), and ECRL is used as the motor and brought around the forearm to
the volar side
Uses free tendons for length
(adhesions)
Requires extensive therapy
postoperatively
Possible crowding of carpal
tunnel can occur
Clawing of the digits and loss of coordinated digital flexion is the most disabling aspect of ulnar nerve
injury and results from intrinsic muscle paralysis in the presence of functioning extrinsic digital flexors
and extensors. Loss of the lumbricals and interossei to the ring and small fingers, which normally
function to flex the MCP joints and extend the PIP and DIP joints, results in hyperextension at the MCP
due to the unopposed pull of the extrinsic digital extensors. Furthermore, the unopposed pull of the FDP
tendons produces flexion at the DIP and PIP joints, which results in the characteristic claw position: MCP
joint hyperextension and IP joint flexion of the ring and small fingers.
An additional and functionally devastating complication of intrinsic muscle paralysis is the loss of
coordinated finger flexion. A normal grasp begins with MCP flexion, initiated by the lumbricals which
arise from the tendons of the FDP, and is followed by IP joint flexion. With clawing, the lumbricals are
nonfunctional, and grasp is initiated by the extrinsic digital flexors. As a result, flexion begins distally at
the DIP joint and is often coupled with MCP hyperextension (from the radial nerve), which results in
objects being pushed out of the hand instead of encircled by the digits.
Patients with high ulnar nerve palsy will experience loss of sensation of the dorsal-ulnar hand, loss of
FDP function to the ring and small fingers, and FCU paralysis. Paradoxically, clawing is less severe in
high ulnar nerve palsy as the FDP paralysis lessens the flexion forces on the PIP and DIP joints of the ring
and small fingers. Although sensory nerve transfers have been described for the dorsal-ulnar hand, these
are not routine, as the sensory deficit is not as disabling as that seen with median nerve 
 injuries. 4,36
The primary functional losses with ulnar nerve palsy are key pinch and grasp, due to both clawing and
loss of coordinated finger flexion. Patients with high ulnar nerve palsy will also lack active DIP joint
flexion in the ring and small fingers. Wrist flexion is typically preserved through the FCR, and the
functional losses from inability to abduct and adduct the digits are minimal. As previously discussed, the
FCU paralysis does not result in demonstrable grip weakness. 26 Therefore, the goals of reconstruction in
ulnar nerve palsy are as follows:
DIP joint flexion in ring and small fingers (high palsy only)
Thumb adduction (key pinch)
Correct clawing/restored digital flexion
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With high ulnar nerve palsy, restoring active DIP joint flexion in the ring and small fingers is easily
accomplished with a side-to-side tenodesis of these tendons to the functional FDP tendons of the long
finger. This extrinsic transfer should typically be performed before correcting clawing to enable the
patient to make a strong, full fist after correcting the intrinsic paralysis. It should be noted that this
transfer will worsen clawing due to the pull of the FDP tendons until the intrinsic muscle function can be
restored with an intrinsic tendon transfer.
Key pinch is a combination of thumb adduction through the AP and index finger abduction through the
first dorsal interosseous muscle. Procedures to restore key pinch (adductorplasty) only need to restore
thumb adduction as the index finger can be stabilized against the adjacent digits, obviating the need for
active index finger abduction. Many donor muscles have been described to restore thumb adduction,
including wrist flexors, digital flexors and extensors, and the BR. The ECRB 37 and BR are both commonly
used to restore thumb adduction; both must be lengthened with free tendon grafts and passed from
dorsal to volar in the third intermetacarpal space, using the second metacarpal as a pulley and orienting
the vector of pull in a line parallel to the AP (Figure 79.5). The FDS tendons to the long and ring fingers
have also been used for adductorplasty. 38 These are divided distally in the digit, retrieved in the palm,
and routed in the retroflexor space to reach the AP insertion. Although the FDS tendons have good
independent control and excursion, this vector does not mimic that of the AP as well as the ECRB or BR
do. Furthermore, the sacrifice of an FDS tendon may weaken grip in these patients who already suffer
from a loss of grip strength and can sometimes lead to PIP joint hyperextension. Importantly, the ring
finger FDS must never be sacrificed in a patient with high ulnar nerve palsy, as this will leave them
without an extrinsic flexor to the ring finger. Digital extensors, including the EIP, EDC-index, and EDQ
have also been described as transfers to restore thumb adduction, but these are often weak motors with
suboptimal vectors of pull.
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FIGURE 79.5 Extensor carpi radialis brevis adductorplasty. The extensor carpi radialis brevis is extended with a free tendon
graft and passed around the third metacarpal (pulley) before inserting into the abductor tubercle or APB tendon.
Physical examination is critical in selecting the appropriate procedure to correct the clawed hand. The
Bouvier test involves passively flexing the MCP joints and asking the patient to actively extend the IP
joints. If the patient is able to fully extend the IP joints through the extrinsic digital extensors with the
MCP joints flexed, the Bouvier test is positive and the clawing is considered simple (static). In these cases,
only the MCP joint hyperextension deformity must be corrected. If the extrinsic extensors are unable to
extend the IP joints with the MCP joints passively flexed, the Bouvier test is negative and the clawing is
considered complex (dynamic). In these cases, the central slip is attenuated, and a tendon transfer must
provide IP joint extension in addition to correcting the MCP joint hyperextension deformity.
In the case of simple clawing, several static procedures have demonstrated clinical success in preventing
MCP hyperextension, including osseous blocks on the dorsal metacarpal head, 39 volar (Zancolli) MCP
joint capsulodesis, 40 and free tendon grafts from the deep intermetacarpal ligament, passed through the
lumbrical canal, and secured to the extensor mechanism. 41 Fowler and Tsuge popularized a dynamic
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tenodesis procedure, where a tendon graft is looped through the extensor retinaculum of the wrist, and
each end is split in half. The four free ends are then routed along the lumbrical canals and inserted into
the lateral bands to provide MCP joint flexion and IP joint extension with wrist flexion 42,43 (Figure 79.6).
These procedures are best reserved for patients with a positive Bouvier test (simple clawing).

FIGURE 79.6 Dynamic tenodesis for claw hand correction. A free tendon graft is anchored in the extensor retinaculum and
each of four slips is passed through the lumbrical canal to insert into the lateral bands.
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Transfers of the FDS can be used to correct both simple and complex clawing. In both cases, the tendons
are divided distally, retrieved in the palm, and split into four tails that are passed to the fingers via the
lumbrical canals (Figure 79.7). If only MCP hyperextension is to be corrected (simple clawing), the
transfers can be inserted into the A1 or A2 pulleys 44 or into the proximal phalanx itself 45 (Figure 79.8). If
a superficialis transfer must also provide IP joint extension, the modified Stiles-Bunnell procedure
describes insertion into the lateral band. 46 It should be noted that in this procedure, sacrifice of the FDS
tendon—the primary flexor of the PIP joint—and simultaneous increase in the extension force on the PIP
joint by inserting into the lateral bands can increase the risk of PIP joint hyperextension and swan neck
deformity. This risk can be minimized by suturing one of the distal slips of the FDS remnant across the
PIP joint to act as a checkrein to prevent hyperextension or by only performing this procedure in patients
with stable joints that cannot be passively hyperextended. The primary drawback to all superficialis
transfers is that they may further diminish grip strength.
FIGURE 79.7 Brand flexor carpi radialis tendon transfer for ulnar nerve palsy. A. A free tendon graft is harvested and divided
into four equal slips. B. The radial lateral bands are identified and isolated with vessel loops and the free tendon grafts are laid
out in the position of the transfer. C. A curved tendon passer is used to deliver the tendons through the lumbrical canal of each
finger to perform the distal tenorrhaphy first. D. The tension of the transfer is set using a rolled towel to simulate a functional
grasp position.
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FIGURE 79.8 Classic insertion sites for flexor digitorum superficialis tendon transfers to correct clawing: lateral band (A),
proximal phalanx (B), and flexor tendon sheath (C).
In an effort to integrate MCP and IP joint flexion while maintaining—or even improving—grip strength,
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several authors have described transfers utilizing wrist flexors and extensors as donor muscles to correct
clawing (Figure 79.9). 47–49 In a similar fashion, these donors are all lengthened with a tendon graft that is
split into four tails distally and routed through the lumbrical canals to reach their insertion on the lateral
bands. The ECRL, ECRB, FCR, or BR muscles may be used for this transfer, although the wrist extensors
provide a higher degree of synergy by coupling wrist extension with grasp. In addition to improving grip
strength, the preservation of the FDS tendons in these procedures also minimizes the risk for PIP joint
hyperextension deformity.
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FIGURE 79.9 Transfer of elongated extensor carpi radialis longus to the radial lateral bands of the ring and small fingers for
dynamic correction of clawing.
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Tendon Transfers for Combined Palsies and Other Injuries
Patients with combined nerve injuries present a much more difficult problem as the muscles available for
transfer become more limited. These patients require an individualized approach that addresses their
specific functional priorities. It is often necessary to combine tendon transfers with adjunctive measures,
including splinting, tenodesis, nerve transfer, free functional muscle transfer, or selective arthrodesis, to
improve function in these patients. Tendon transfers can also be used to restore function in patients with
brachial plexus injury or tetraplegia, but such procedures are beyond the scope of this chapter. Interested
readers are referred to several excellent review articles available on these subjects. 10,50
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Postoperative Management
Tendon transfers must be allowed sufficient time to heal before formal therapy can begin.
Postoperatively, patients are immobilized in a cast or splint for 4 weeks before transitioning into a
removable orthosis, at which time gentle mobilization exercises are initiated. Passive- or active-assisted
exercises are continued for an additional 4 weeks, and patients may gradually begin strengthening
exercises at 8 weeks postoperative. By 12 weeks, the tendons should be fully healed, and a gradual return
to full activity is advocated. The amount of reeducation necessary will depend on several factors,
including the timing and nature of injury, age of the patient, specific transfers performed, and patient
motivation.
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Questions
1. A patient with high ulnar and median nerve palsy needs an opponensplasty to improve thumb
function. The most appropriate tendon transfer is:
a. EIP
b. EPL
c. EDQ
d. Ring finger FDP
e. ADM
2. Tendon transfers that attempt to replicate the function of which muscle provides the best thumb
opposition?
a. FPL
b. Opponens pollicis (OPP)
c. FPB
d. APB
e. AP
3. A patient with known ulnar nerve palsy is unable to actively extend the proximal IP joint of the
small finger and exhibits clawing. During physical examination, the MCP joint is stabilized in neutral
(0°). The patient is then able to extend the proximal IP joint. What muscle acts alone to extend the
proximal IP joint in this circumstance?
a. Lumbrical
b. Dorsal interosseous
c. Volar interosseous
d. EDC
e. ADM
4. A 44-year-old man undergoes an elbow arthroscopy and immediately postoperatively, the patient
is unable to extend his thumb and fingers. These functions never recover, and tendon transfers are
planned. Which of the following tendon transfers would be preferred for this patient?
a. PT to ECRL, FCR to EDC, PL to EPL
b. FCR to ECRB, PL to EPL
c. FCU to ECRB, FCR to EPL
d. FCR to EDC, PL to EPL
e. PT to ECU, FCR to EDC, PL to APL
5. Which one of the following muscles has a similar relative strength to the FCU?
a. BR
b. ECU
c. ECRL
d. APL
e. FPL
6. Which surgical procedures will improve hand function in a patient with high median nerve palsy?
a. Ring finger FDS transfer for thumb opposition, BR to the flexor pollicis longus, and FDP of the
ring and small fingers side by side to the long and index fingers
b. EIP to APB for thumb opposition, BR to flexor pollicis longus, and FDP of ring and small
fingers side by side to the long and index fingers
c. Flexor carpi ulnar transfer prolonged with a PL graft for thumb opposition, thumb IP joint
arthrodesis, and extensor carpi radialis brevis to the FDP of the index and long fingers
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d. Thumb abduction bone block, transfer of the FCU to the FDP, and BR to flexor pollicis longus
e. BR transfer prolonged with a PL graft for thumb opposition, extensor carpi radialis brevis to
the FDP of index and long fingers, and arthrodesis of the thumb IP joint
1. Answer: a. The EIP transfer is appropriate for opponensplasty in patients with a supple hand. The
EIP opponensplasty produces good results in restoration of thumb opposition. The EIP is expendable
with minimal donor site morbidity, is of sufficient length, and has an optimal line of pull to provide a
superior mechanical advantage and a favorable torque when compared with FDS. EPL and EDQ are
not suitable for this clinical situation. The remaining alternatives are not available with the high
ulnar and median nerve palsies that this patient has.
2. Answer: d. Opposition of the thumb results from the abduction, flexion and rotation of the
carpometacarpal joint of the thumb and abduction of the MCP joint. The APB, OPP, and superficial
head of the FPB produce thumb abduction, and their simultaneous action on both the thumb CMC
joint and MCP joint produces thumb opposition. The APB is the primary mover of the thumb as it
provides the correct direction of action and proper insertion to produce full thumb opposition. The
OPP is an important but less effective muscle in opposition. The FPB is a stronger flexor than the
abductor and together they provide for strong key and tip pinch. Based on muscle excursion and
tension fraction, the best muscles to use in transfer for thumb opposition are the FDS of the long
finger, ECU, FDS of the ring finger and ECRL. A pulley in the area of the pisiform restores the
necessary direction of action.
3. Answer: d. Bouvier’s maneuver is a clinical sign of ulnar nerve dysfunction. It allows the isolation
of the components of clawing in a hand with severe intrinsic dysfunction. Patients with a positive
test are unable to use their extensor digitorum to extend the PIP joint because of intrinsic weakness
and the relative shortening of the length over which the extensor digitorum must act. By stabilizing
the MCP joint in neutral to slight flexion, the EDC is then able to extend the PIP joint from its flexed
position.
4. Answer: d. The patient most likely has a PIN injury distal to the innervation of the ECRB and
ECRL, preserving wrist extension. Thus, the primary defects are finger and thumb extension. The
best answer for treatment of these deficits includes FCR to EDC and PL to EPL.
5. Answer: a. When designing tendon transfers, matching the relative strength of muscles is helpful.
Although not always possible, matching a muscle deficit with a muscle transfer of similar relative
strength is preferred. The strengths of the muscles in the forearm have been compared to the FCR
which was given a relative strength of one. The FCR, ECRL, ECRB, ECU, PT, FPL, FDS, FDP, and
APL all have a relative strength of one. The FCU and BR have a relative strength of 2. The strength is
related to the cross-sectional area of the muscle.
6. Answer: b. This patient has a classic high median nerve lesion. The missing functions that need to
be restored are thumb opposition and flexion of the thumb, index, and long fingers. The best set of
transfers listed is the rerouted EIP into the APB for thumb opposition, BR to FPL, and FDP side to
side of ring/small to index/long finger. When there are enough available transfers to restore the
missing function, a tendon transfer is better than an arthrodesis. A thumb abduction block does not
provide for thumb opposition, and a transfer for opposition is better. The BR prolonged with a graft
would not provide the correct line of pull for thumb opposition unless it were routed more ulnarly
through the hand. Option a would be reasonable, but it is better to sacrifice a wrist extensor than the
superficialis to the ring finger for thumb opposition, especially because the ring profundus is now
going to have to provide flexion for the long and index along with the side-to-side transfer.
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Chuinard, RG, Boyes, JH, Stark, HH, Ashworth, CR. Tendon transfers for radial nerve palsy: use of superficialis tendons for digital
extension. J Hand Surg. 1978;3(6):560-570.
Raskin, KB, Wilgis, EF. Flexor carpi ulnaris transfer for radial nerve palsy: functional testing of long-term results. J Hand Surg. 1995;20(5):737-
742.
Chadderdon, RC, Gaston, RG. Low median nerve transfers (opponensplasty). Hand Clin. 2016;32(3):349-359.A thorough and in-depth discussion
of thumb mechanics and the various options available for opponensplasty.
Foucher, G, Malizos, C, Sammut, D, et al. Primary palmaris longus transfer as an opponensplasty in carpal tunnel release: a series of 73 cases.
J Hand Surg (Edinb). 1991;16(1):56-60.
Royle, ND. An operation for paralysis of the intrinsic muscles of the thumb. JAMA. 1938;111(7):612-613.
Bunnell, S. Opposition of the thumb. J Bone Joint Surg Am. 1938;20A:269-284.
Thompson, TC. A modified operation for opponens paralysis. J Bone Joint Surg Am. 1942;24A:632-640.
Wood, VE, Adams, J. Complications of opponensplasty with transfer of extensor carpi ulnaris to extensor pollicis brevis. J Hand Surg.
1984;9(5):699-704.
Zancolli, EA. Paralytic supination contracture of the forearm. J Bone Joint Surg Am. 1967;49(7):1275-1284.
Cliffton, EE. Unusual innervation of the intrinsic muscles of the hand by median and ulnar nerve. Surgery. 1948;23(1):12-31.
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Leibovic, SJ, Hastings, H II. Martin-Gruber revisited. J Hand Surg. 1992;17(1):47-53.
Ozkan, T, Ozer, K, Gulgonen, A. Restoration of sensibility in irreparable ulnar and median nerve lesions with use of sensory nerve transfer:
long-term follow-up of 20 cases. J Hand Surg. 2001;26(1):44-51.
Smith, RJ. Extensor carpi radialis brevis tendon transfer for thumb adduction: a study of power pinch. J Hand Surg. 1983;8(1):4-15.
Hamlin, C, Littler, JW. Restoration of power pinch. J Hand Surg. 1980;5(4):396-401.
Mikhail, IK. Bone block operation for clawhand. Surg Gynecol Obstet. 1964;118:1077-1079.
Zancolli, EA. Claw-hand caused by paralysis of the intrinsic muscles: a simple surgical procedure for its correction. J Bone Joint Surg Am.
1957;39A:1076-1080.
Parkes, A. Paralytic claw fingers: a graft tenodesis operation. Hand. 1973;5(3):192-199.
Riordan, DC. Tendon transplantations in median-nerve and ulnar-nerve paralysis. J Bone Joint Surg Am. 1953;35A:312-320.
Tsuge, K. Tendon transfers in median and ulnar nerve paralysis. Hiroshima J Med Sci. 1967;16(1):29-48.
Hastings, H II, McCollam, SM. Flexor digitorum superficialis lasso tendon transfer in isolated ulnar nerve palsy: a functional evaluation. J
Hand Surg. 1994;19(2):275-280.
Burkhalter, WE, Strait, JL. Metacarpophalangeal flexor replacement for intrinsic-muscle paralysis. J Bone Joint Surg Am. 1973;55A:1667-1676.
Bunnell, S. Surgery of the intrinsic muscles of the hand other than those producing opposition of the thumb. J Bone Joint Surg Am. 1942;24A:1-
31.
Burkhalter, WE. Restoration of power grip in ulnar nerve paralysis. Orthop Clin North Am. 1974;5(2):289-303.
Enna, CD, Riordan, DC. The Fowler procedure for correction of the paralytic claw hand. Plast Reconstr Surg. 1973;52(4):352-360.
Brand, PW. Tendon grafting. J Bone Joint Surg Br. 1961;43B:444-453.
Bednar, MS. Tendon transfers for tetraplegia. Hand Clin. 2016;32(3):389-396.
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C H A P T E R 8 0
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Ligament Injuries of the Hand
Aviram M. Giladi and Kevin C. Chung
Key points
If a proximal interphalangeal (PIP) fracture/dislocation remains reduced and congruent when
splinted at 30° of flexion or less, it is considered stable and can be treated closed.
Many unstable PIP fracture/dislocation injuries, historically treated with open fixation, are now
amenable to treatment with dynamic external fixation, facilitating earlier range of motion and
improving long-term outcomes.
For failed primary treatment of unstable PIP fracture/dislocation injuries with destruction of the
volar base of the middle phalanx, or for those that present more than 4 to 6 weeks after injury, the
hemihamate arthroplasty is a reliable option for joint reconstruction.
An acute boutonniere deformity, with DIP extended and PIP flexed, raises concern for a central slip
rupture. This can be tested with Elson’s test.
Avoid longitudinal traction when attempting reductions of metacarpophalangeal dislocations—this
can entrap the metacarpal head and prevent a successful reduction.
Maintain suspicion for finger carpometacarpal (CMC) joint dislocation in a patient with trauma,
pain, and swelling over the CMC region even if the X-rays are difficult to evaluate. If dislocation is
suspected but cannot clearly be seen on X-rays, CT scan may be required to evaluate.
Hand ligament injuries are common and present in a variety of ways. Although some of these injuries are
associated with fractures or obvious dislocations, many ligament injuries in the hand are subtle.
Appropriate diagnosis and management of these injuries require in-depth knowledge of anatomy and
biomechanics, along with thoughtful evaluation and careful examination. In this chapter, we review
many of the more common hand ligament injuries, and present the associated anatomy, biomechanics,
related pathology, and treatment options for each.
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Proximal Interphalangeal Joint Injuries
Proximal interphalangeal joint (PIPJ) injuries are common and fall in to three major categories 1,2 :
Dislocations
Avulsions
Fracture-dislocations
Postinjury stiffness is a substantial problem and is often made worse by improper or prolonged
immobilization even within the first 2 weeks after injury. Early treatment is critical.
The PIPJ is a bicondylar hinge with an arc of motion of 110° in a single plane. It accounts for 20% of the
total arc of motion of the finger. The major soft tissue contributors to joint stability are the volar plate and
the collateral ligaments (Figure 80.1). The collateral ligaments on the ulnar and radial side are composed
of two segments, an accessory collateral ligament (more volar) and a proper collateral ligament (more
dorsal). The extensor system provides the least amount of support, which makes the joint inherently less
stable to dorsal forces. As a result, dorsal dislocations are most common, with the middle phalanx being
driven dorsally and then proximally. Lateral and volar dislocations are much less common.
FIGURE 80.1 Anatomy of the PIP joint. Note the volar and lateral stabilizing structures, especially the volar plate and the
collateral ligaments. The proper collateral ligament attaches to the middle phalanx and the accessory collateral ligament
attaches to the volar plate.
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PIPJ Dislocation
Generally, the approach to PIPJ dislocations is as follows:
Reduction
Evaluate postreduction for joint congruency through the arc of motion
Assess stability
If the joint is stable following reduction, nonoperative treatment is generally the best option, and early
hand therapy should be used to minimize stiffness. Unstable joints, including those that frankly
redisplace after reduction as well as those that do not maintain congruency through the arc of motion,
often require operative management. 3,4
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Evaluation
A thorough history will help clarify the mechanism and direction of forces.
Radiographs are done to assess for any associated fractures or avulsion fragments (which may represent
ligamentous avulsions) and to see the resting joint congruency:
True lateral view of the involved finger
Anteroposterior or posteroanterior (PA) view of the involved finger
If evaluating an acute injury that is in need of reduction:
Perform a sensory exam.
Provide a digital block to make the reduction maneuver less painful and more likely to succeed.
Perform the reduction.
The reduction maneuver includes hyperextension of the PIPJ following by gentle pressure on the
base of the middle phalanx along with axial traction.
Use fluoroscopic guidance when available.
Avoid multiple attempts at closed reduction.
Irreducible dislocation can be caused by interposed soft tissues, and repeated attempts can
create additional tissue and/or articular injury.
For dorsal dislocations, the volar plate is most often interposed, although the profundus
tendon or part of the extensor mechanism can become entrapped and block reduction.
In these cases, open reduction is indicated.
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If Closed Reduction Is Successful:
Assess for tendon function and joint stability.
Repeat radiographs after reduction to evaluate for congruency and for any subtle fractures that may
have been missed.
Palpate the ligamentous structures to help identify focal areas of pain and potential injury (remember
this may be altered by local anesthesia).
It is important to passively stress the joint with radial/ulnar pressure and volar/dorsal translation, as well
as to test stability through active motion. Of note, radial/ulnar stressing to test collateral ligament stability
should be done with the finger extended to test the accessory collateral, and with the PIPJ at 30° to test the
proper collateral. Evaluating joint congruency under fluoroscopy during active motion is the optimal way
to test active stability. If the joint is stable after reduction, buddy straps/taping to facilitate early motion
with some protection is the optimal treatment, rather than immobilization. If the subluxation or
dislocation recurs with active motion, splinting in a position of stability—15° to 30° of flexion—may be
required to facilitate ligament healing before allowing motion.
Dorsal PIPJ dislocation: This is the most common PIPJ injury, often occurring because of
hyperextension with axial loading (Figure 80.2).
Type I (hyperextension): Hyperextension results in avulsion of the volar plate from the proximal
phalanx. However, some contact is usually maintained between the head of the proximal phalanx
and the base of the middle phalanx, facilitated by the stable collateral ligaments. This is not a
complete dislocation.
Type II (dorsal dislocation): Volar plate avulsion along with separation between the accessory and
proper collateral ligaments, allowing complete dorsal dislocation of the middle phalanx that then
tends to pull proximally into a bayonet configuration. The proper collateral often remains intact. As
long as they can be reduced, type I and II injuries rarely require surgical treatment.
Type III (fracture-dislocation): An additional component of impaction fracture at the volar base of the
middle phalanx makes these types of injuries more complicated. Generally, the lip fragment remains
attached to the volar plate and collateral ligament, whereas the rest of the middle phalanx dislocates
dorsally. Additional X-rays of the finger after reduction can help evaluate subtle bony injuries.
Stability of these injuries is largely dependent on the amount of the joint surface that is involved with
the fracture, and some mild flexion may be needed to restabilize the joint.
Stable fractures tend to involve 30% or less of the articular surface.
Some fractures between 30% and 50% will have stability although many will not.
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FIGURE 80.2 Dorsal PIP dislocation types (Eaton classification). Type I represents a hyperextension that results in volar plate
injury with associated minor tear between the collaterals; however, the joint remains congruent. Type II completely disrupts the
volar plate along with a complete tear between the collateral ligaments. The middle phalanx will shift dorsal and the joint is no
longer congruent. Type III involves a fracture and dislocation component. The volar plate, as well as accessory and proper
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collateral ligaments, is damaged, and the volar lip fracture segment stays with these soft tissue elements as the rest of the
middle phalanx shifts dorsally and proximally.
The stable fracture-dislocations tend to have the proper collateral on the middle phalanx shaft segment,
facilitating postreduction stability, whereas those with more articular surface involvement often have
both collateral segments on the broken lip segment, which confers no stability to the reduced middle
phalanx. Some of these injuries are obviously unstable after reduction and easily redislocate; however,
subtle findings of instability during joint motion—including the dorsal V sign (Figure 80.3)—must be
evaluated before accepting the reduction as stable. As long as the joint exhibits stability at 30° of flexion
or less, it can be considered stable.
FIGURE 80.3 Dorsal V sign. A. X-ray of a reduced fracture/dislocation injury demonstrating persistent instability with resultant
dorsal V sign. This PIP is hinging, rather than maintaining appropriate congruent alignment and gliding. B. Illustration of the
dorsal V, indicating persistent PIP instability.
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Treatment
No matter the treatment, the pain, swelling, and stiffness from these injuries may last for months. The
unstable injuries, especially the unstable fracture-dislocations, are prone to long-term stiffness, flexion
contracture, and functional limitations. The patient should be counseled about these issues early to help
guide expectations.
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Stable PIPJ
Almost all type I and II injuries are stable after reduction and can be treated nonoperatively with buddy
straps. For patients with stability but substantial discomfort, extension block splinting, preventing full
extension of the joint, may be helpful.
Active motion therapy should begin within 2 or 3 days of injury.
Beginning this range of motion therapy within the splint maintains reduction while preventing
painful full extension.
For stable joints with more structural injury requiring mild flexion to reach full stability, mostly fracture-
dislocation injuries of 30% to 40% or less, extension block splinting may be needed for up to 4 weeks. 5
Initiate early range of motion within the splint.
The splint can be set to start at 30° of flexion to provide stability and be adjusted into extension
progressively (e.g., 10° per week) so that the patient slowly gets to full extension over 4 weeks while
maintaining range of motion in flexion within the splint.
If the fracture component risks instability with early extension, the splint can be maintained in the
flexed position for longer, but no longer than 3 weeks at 20° to 30° to avoid flexion contracture.
In some cases, extension block pinning may be used. 6 This requires passing a Kirschner wire (K-wire)
through the proximal phalanx head to structurally block full proximal interphalangeal (PIP) extension.
Although this does prevent dorsal translation of the middle phalanx, the downsides are a surgical
procedure with complication risks that is not amenable to progressive straightening. Therefore, splinting
tends to be a better option if the patient can tolerate it and comply with the protocol.
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Unstable PIPJ
These injuries—most often fracture-dislocations with greater joint surface area involvement—are difficult
to treat. Outcomes are often disappointing even with optimal treatment. The goal of treatment is to
restore congruity and facilitate early active motion. There are numerous options:
Dynamic external fixation/dynamic skeletal traction 7-9 : The traction from the fixator system creates
tension in the soft tissue envelope that helps hold fracture fragments in reduction and stable, and the
dynamic component allows for range of motion while traction is maintained (Figure 80.4).
Open reduction and internal fixation: If the volar fragment is not comminuted and is large enough for a
screw, it may be amenable to direct repair with a lag screw.
K-wire fixation: A single K-wire is driven across the fracture site and then across the PIPJ with joint at
20° to 30° of flexion. Pin is removed at 3 weeks.
Volar plate arthroplasty: Especially useful when the fracture is comminuted and restoring joint surface
is not feasible. This technique uses the volar plate and anchors it in the fracture defect to resurface
the middle phalanx base. 10 This holds the PIPJ in mild flexion, and although it does restore stability,
the risk of flexion contracture is high.
Hemihamate osteochondral arthroplasty: When the volar base of the middle phalanx is comminuted and
unstable, but the dorsal base remains intact, reconstruction of the PIPJ is possible using a
nonvascularized osteochondral graft taken from the dorsal distal articular surface of the hamate. This
technique can also be useful for fractures that may have been amenable to dynamic external fixation
or open reduction and internal fixation (ORIF) but did not present acutely. The articulation between
the hamate and the small and ring finger metacarpal bases, notable for having a dorsal central ridge
that is an excellent anatomic match to the volar base of the middle phalanx, can be contoured to fit
the defect and recapitulate the PIPJ (Figure 80.5). The graft is secured with screws, and range of
motion can be started 1 week after surgery. Long-term outcomes of this procedure have an average
range of motion between 50° and 75° of PIP flexion, with many patients having a persistent flexion
contracture even if active range of motion has improved overall. 11,12
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FIGURE 80.4 Dynamic external fixator. A. Unstable fracture/dislocation of left ring finger PIP joint. B. Dynamic external fixator
placed using K-wire and rubber band construct. C. Traction via dynamic fixator improves joint alignment and facilitates early
motion.
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FIGURE 80.5 Hemihamate arthroplasty of the ring finger PIP joint. A. Chronic unstable fracture-dislocation of the ring finger
PIP joint. B. Reconstruction of the volar base of the ring finger middle phalanx using a hemihamate autograft, recreating PIP
articular architecture
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Volar PIPJ Dislocation and Central Slip Injuries
Volar PIPJ dislocation is rare. If a volar PIPJ dislocation is identified, it is usually facilitated by either
rupture of the central slip of the extensor tendon or torsion force causing volar-directed rotatory
subluxation of the middle phalanx. A central slip rupture may be associated with an avulsion fracture of
the dorsal base of the middle phalanx, but some slip ruptures occur without a fracture and therefore
cannot be seen on X-rays.
If the volar PIPJ dislocation was from a rotatory mechanism, only one of the collateral ligaments may be
injured, whereas a dislocation after central slip rupture often injures both collateral ligaments. Although a
volar dislocation also injures the volar plate and extensor mechanism, closed reduction is usually
attainable with longitudinal traction and extension. However, especially with rotatory injuries, the
condyle of the proximal phalanx can get interposed between the central slip and the lateral band, making
reduction difficult. In this situation, flexing the PIPJ to relax the lateral band (rather than pulling traction)
is necessary before recreating the rotational force to facilitate reduction.
Confirm adequate reduction with X-ray. Test active extension to evaluate the integrity of the central slip.
An acute boutonniere deformity, with extensor lag at the PIPJ and hyperextension of the distal
interphalangeal joint (DIPJ), indicates central slip rupture. Elson’s test can be used to evaluate. This is
performed by holding the PIP in flexion and having the patient attempt to extend the middle phalanx
against resistance—if the DIPJ tightens into extension a central slip rupture has likely occurred. If the
DIPJ remains lax, the central slip is intact.
With no central slip injury, these dislocations should be splinted for approximately 2 weeks and then put
into buddy straps to facility early motion. In the setting of a central slip rupture, 6 weeks of splinting with
the PIPJ in full extension is needed. Even if the central slip rupture is associated with a small avulsion
fragment, closed treatment with 6 weeks of splinting is usually adequate. As long as any finger deformity
associated with the central slip injury is passively correctable, splinting is often adequate even with a
subacute presentation. In the setting of a larger intra-articular fracture fragment that is displaced, ORIF
may be required. If the deformity (i.e., boutonniere) is not passively correctable, surgical intervention is
needed. 13,14
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Lateral PIPJ Injuries
Forced radial or ulnar deviation of the PIPJ puts stress on the contralateral collateral ligament, which may
sustain a partial injury or complete rupture. Often a rupture occurs at the site of the proximal attachment
on the proximal phalanx. This creates joint instability, and due to the force of the injury the PIPJ may
dislocate. More severe injuries can also disrupt the volar plate. Longitudinal traction is usually adequate
for reduction. Once reduced, test for stability through the flexion/extension arc and to lateral stress (as
described earlier). If the reduction is stable, splinting in extension for 7 days followed by protected active
range of motion with buddy straps is the appropriate treatment.
If reduction cannot be accomplished (often due to interposition of soft tissues), or the joint is persistently
unstable, operative intervention is needed. This involves approaching the PIPJ through a midaxial
approach, clearing any entrapped tissues, and reconstructing the collateral ligament by attaching it to the
phalanx with suture anchors. 15,16
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Outcomes and Complications
PIPJ injuries are notorious for causing some amount of stiffness long term, and it is important to counsel
patients about this early. Even for injuries that recover well, the time to recovery can be many months of
edema and pain before resolution. Stiffness and flexion contracture are commonly encountered problems
after these injuries, especially the more severe types with fracture components or complete dislocations
(and associated soft tissue disruption). 17
Collateral stiffness is the most common etiology for loss of range of motion as well as flexion contracture.
Volar plate stiffness contributes as well. First-line treatment for these findings is early aggressive therapy
to restore range of motion. If this is not successful, joint release by releasing the collateral ligaments, and
perhaps also the volar plate, may be required. Even after joint release, range of motion does not return to
preinjury levels. For PIPJ that remain painful and stiff, conversion to arthroplasty or arthrodesis is then
considered.
Long-term instability, although less frequent, can occur due to unrepaired collateral ligament rupture,
persistent collateral ligament laxity, persistent central slip injury, or volar plate laxity. Instability from any
cause can precipitate early degenerative arthritis. Additionally, chronic hyperextension from volar plate
laxity can lead to swan-neck deformity. Unrepaired central slip injuries can result in extensor lag, and if
untreated can progress to boutonniere deformity.
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Finger Distal Interphalangeal Joint/Thumb Interphalangeal Joint
Injuries
The DIPJ is similar to the PIPJ in that it is a hinge joint with strong lateral stabilizers. In addition to volar
and dorsal support structures seen at the PIPJ (e.g., volar plate), the DIPJ benefits from added volar
stability from the insertion of the flexor digitorum profundus (FDP) tendon at the base of the distal
phalanx. The thumb interphalangeal joint (IPJ) is structurally similar, with the flexor pollicis longus (FPL)
tendon providing the added volar structural stability. Even with the support from the tendon insertion,
the finger DIPJ have added hyperextensibility compared to the PIPJ (and IPJ) due to shorter and more
laterally positioned checkrein ligaments. DIPJ/IPJ arc of active motion is about 60°, with an additional 10°
to 15° of passive hyperextension possible for DIPJ.
DIPJ and thumb IPJ dislocations are rare. Often when these dislocations do occur they are associated with
flexor or extensor tendon insertion injuries, which are covered in the flexor and extensor tendon injury
sections. If an isolated DIPJ dislocation occurs, it is almost always a dorsal dislocation. Closed
dislocations can be reduced with longitudinal traction. If successfully reduced, splint for 1 week and then
begin protected active motion in a dorsal blocking splint for an additional 3 weeks. Dorsal dislocations
with an associated dorsal laceration are common and should be irrigated thoroughly before reduction
and closure. If reducible, the same splinting regimen as reducible closed injuries is the appropriate
treatment.
Dorsal DIPJ or thumb IPJ dislocations may be irreducible due to interposition of soft tissue (volar plate,
flexor tendon) or sesamoid bones. 18-20 These cases require operative intervention for open reduction but
are often stable enough to be treated with splinting after the reduction. If not stable, K-wire pinning may
be required. Volar plate arthroplasty is an alternative option, although the potential for flexion
contracture is increased with this approach.
Small fractures of the phalangeal base may occur with dislocation or hyperextension injuries of the DIPJ
and thumb IPJ. Fractures with small fragments that do not destabilize tendon insertions or joint congruity
are generally left alone; however, if the fragment is large and associated with tendon insertion or large
part of the articular surface, operative fixation may be required.
Stiffness and even fusion of the DIPJ and thumb IPJ is much better tolerated than at the PIPJ. Most
surgical procedures required after a DIPJ or thumb IPJ dislocation, and even reduction and splinting
treatments, will result in some stiffness. However, if persistently painful, conversion to a fusion is
tolerated well overall and provides pain relief.
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Finger Metacarpophalangeal Joint Injuries
The finger metacarpophalangeal joints (MCPJ) is a diarthroidal joint and has a complex stabilization
system with contributions from unique bony anatomy, intrinsic components, and extrinsic structures.
The metacarpal head is volarly offset from the shaft. As a result, the arc of rotation moves the articulation
further from the shaft as the joint surface progresses volarly (Figure 80.6). This is a cam mechanism. The
MCPJ intrinsic stabilizers include a volar plate as well as radial and ulnar accessory and collateral
ligaments. Due to the unique bony anatomy of the metacarpal, the collateral ligaments are progressively
tightened as the MCPJ flexes and the proximal phalanx base is moved further volarly compared to the
ligament attachment on the metacarpal. As a result, the joint is relatively lax in extension, and can glide in
abduction and adduction, yet loses much of that lateral gliding as the MCPJ flexes. The MCPJ is therefore
more stable, with the collaterals tight, in full flexion. The volar plate is stout distally but much thinner
proximally. Different from the PIPJ, there are no checkrein ligaments on the MCPJ volar plate. This
facilitates some hyperextension of the MCPJ. The extrinsic stabilizers include flexor tendons, the extensor
mechanism, the sagittal bands, and the transverse intermetacarpal ligament that connects across the volar
plates.

FIGURE 80.6 Anatomy of the metacarpal head, illustrating greater lengths from the center of rotation as the arc progresses
volarly.
Because of these stabilizing components around the metacarpal head, major ligamentous injuries and
dislocations of finger MCPJ are less common than PIPJ. However, this complex anatomy can contribute to
difficulties in management of MCPJ injuries when they do occur.
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Sagittal Band Injuries
Sagittal bands contribute to MCPJ and extensor tendon stability. They attach dorsally to the extensor
hood and run palmar to insert on the volar plate. They function as the primary lateral stabilizer for the
extensor tendon over the MCPJ. Sagittal band rupture results in subluxation or complete dislocation of
the extensor tendon during MCPJ flexion and extension. Injury is often identified by subluxation and
associated localized pain and edema. The diagnosis is usually made clinically, but ultrasound or MRI can
provide confirmation in unclear cases.
For injuries with pain and minimal tendon instability, 4 to 6 weeks of conservative treatment in a splint
that holds the affected metacarpophalangeal (MCP) neutral or mildly hyperextended is appropriate. If
subluxation or dislocation is identified within 6 weeks of injury, conservative treatment is appropriate
first-line treatment for most patients. Even for patients who present with longer delay, a trial of
conservative management is often still indicated. 21
For athletes and very high demand patients who present with complete dislocation, early surgical
intervention may be appropriate, as this facilitates primary repair of the sagittal band. For most patients,
conservative first-line treatment is appropriate as described earlier; however, if painful subluxation or
dislocation persists, then sagittal band reconstruction is appropriate to correct the abnormality and
decrease pain. 22,23
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Isolated Finger MCPJ Collateral Ligament Injuries
These injuries are rare and when they occur may be associated with a fracture of the base of the proximal
phalanx. 24 Appropriate treatment is important, especially for radial-sided injuries, as the radial collateral
ligament (RCL) is important to stabilize against pinch forces. Visualizing fractures associated with
collateral injuries, especially when they are small avulsion types, can be difficult; a Brewerton view X-ray
may be helpful. Physical examination with stress testing is important, similar to collateral testing of the
PIPJ. For the MCPJ, flex as far as 60° and then test stability against radial and ulnar stress.
If the joint is stable with a firm end point, 4 weeks of dorsal block splinting in 30° to 60° of flexion with
early active motion is appropriate treatment. If the examination identifies a complete tear, or there is an
avulsion fracture associated with an unstable joint, surgical repair is often required.
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Finger MCPJ Dislocations
Finger MCPJ dislocations, when they occur, are usually dorsal or ulnar. They occur most commonly to
the border digits (index or small finger).
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Dorsal MCPJ Dislocations
These injuries often occur after forced hyperextension. This results in injury to the volar plate, at the
thinner proximal segment. Upon presentation, the degree of deformity can indicate the severity of the
injury; however, the more noticeably deformed joints, often with MCPJ held in fixed hyperextension of
60° to 80°, are the result of a simple subluxation. The proximal phalanx base remains in continuity with the
metacarpal head and, as a result, is amenable to closed reduction. The more inconspicuous complete dorsal
dislocation may have a subtle presentation, as the proximal phalanx has completely dislocated into a
bayonet position atop the metacarpal head, leaving the finger in a relatively straight resting position. This
injury is more challenging, and these dislocations can become complex dislocations as the torn volar plate
can interpose between the phalanx and the metacarpal, blocking reduction. 25 Additionally, the
metacarpal head can translate volar and buttonhole between the lumbrical radially and the FDP tendon
ulnarly. This can form a noose around the metacarpal neck.
For the simple dislocation, and even the subluxation, traction should be avoided so that the volar plate is
kept out of the joint space—undue traction can create a complex dislocation. Additionally, any
hyperextension or traction forces used to attempt reduction will make the tendon noose tighter on the
metacarpal neck, preventing reduction. Therefore, closed reduction of a dorsal MCPJ injury should be
done with PIPJ and wrist flexed (to relax the flexor tendons as much as possible), and with volar- and
distal-directed pressure along the base of the proximal phalanx so that it slides over the metacarpal head
without losing contact.
Complex dislocations require operative intervention for open reduction. The approach can be volar or
dorsal, with different risks and benefits. The volar approach is considered higher risk because the volar
displacement of the metacarpal head displaces the neurovascular bundles toward the skin, directly at risk
during the surgical approach. 26 However, the volar approach allows for direct visualization of the tendon
noose around the metacarpal head and facilitates an A1 pulley release that may be all that is needed to
free the metacarpal. 27 The dorsal approach is perceived to be safer and more efficient, and allows direct
visualization of the interposed volar plate, but freeing the tendon noose may be more challenging. 28
After closed or open treatment, radiographically confirm adequate reduction. The patient should then be
placed in a dorsal blocking splint for 4 weeks to prevent MCPJ hyperextension while facilitating early
active range of motion.
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Volar MCPJ Dislocations
Volar MCPJ dislocations are rare, because the volar force required to cause the dislocation is more likely
to fracture the proximal phalanx. However, when these injuries occur, they may be amenable to closed
reduction under sedation. The reduction can be blocked by soft tissue interposition, as dorsal capsule,
distal volar plate, collateral ligament, or junctura can all become entrapped. 29 Open reduction would then
be required.
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Thumb Metacarpophalangeal Joint Injuries
The thumb metacarpophalangeal joint (tMCPJ) has properties of a hinge (ginglymus) joint as well as a
condyloid joint, facilitating movement in a flexion-extension arc as well as some elements of rotation and
abduction-adduction. Natural anatomic variation in the metacarpal head results in a wide range of normal
motion in the population. Most of the tMCPJ stability is from soft tissue. These stabilizing structures
include collateral ligaments and the volar plate. Additionally, the adductor pollicis inserts into the ulnar
sesamoid while the flexor pollicis brevis and abductor pollicis brevis insert into the radial sesamoid.
These sesamoid attachments are at the distal margin of the volar plate, and provide volar stability to the
tMCPJ. These muscular attachments also have fibrous connections to the extensor mechanism, thereby
providing lateral stability as well. Dorsal stability is less stout, provided mostly by the extensor pollicis
longus and brevis tendons passing over the joint, along with some strength from the joint capsule itself.
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Acute Thumb MCPJ Ulnar Collateral Ligament Injuries
Ulnar collateral ligament (UCL) tear is the most common injury to the tMCPJ. 30-32 It occurs due to
hyperabduction and forced radial deviation of the proximal phalanx. Examination will reveal pain and
edema along the ulnar border, particularly over the MCPJ. The most common injury type involves
avulsion off of the distal attachment on the proximal phalanx. In evaluating these injuries, it is important
to discern a partial from a complete tear, identify any fractures, and evaluate for a Stener lesion
(described below). Always remember to examine the uninjured thumb as well, as many patients have
laxity in these joints/ligaments at baseline.
Partial tears and small avulsion fractures that are stable can be treated conservatively in a thumb spica
splint for 4 to 6 weeks. 33 MCP should be ulnarly deviated in the splint, and IPJ can be left free. 
 A
complete tear should be repaired. However, it is important to discern if a Stener lesion is present. A
Stener lesion occurs when the UCL is torn away from the distal attachment on the proximal phalanx and
mobilizes enough to allow the adductor pollicis aponeurosis to interpose between the ligament and the
insertion site. Stener lesions can occur with an associated avulsion fracture or with the ligament alone.
Considering all of this, UCL evaluation involves an important series of steps. 34 Collateral ligament testing
is similar to as described above for PIPJ injuries, with examination in full extension as well as 30° of joint
flexion (Figure 80.7). Pain, as well as adductor pollicis spasm, can make the examination difficult, so a
local anesthetic block may be helpful.
Valgus stress is placed on the joint, evaluate the amount of gapping or angulation that can be
created; this is where a comparison to the normal side is important.
If there is a firm endpoint, it is likely a partial tear; if there is no resistance, the ligament is likely
completely torn.
If the joint can be stressed to >35° of angulation, complete ligament tear is likely.
If this occurs with joint flexed, it is a proper collateral tear.
If this occurs with joint fully extended, it is an accessory collateral tear.
If the joint can be stressed >15° more than contralateral, a complete tear is likely.
If a mass is palpable proximal to the tMCPJ, this may indicate a Stener lesion. However, the absence
of this finding does not rule it out.
Evaluate X-rays because avulsion fractures are common.
Is the avulsion displaced?
More than 2 mm of displacement?
Is it proximal to the level of the adductor hood? If so, this is likely a bony Stener lesion
(Figure 80.8).
Is 20% or more of the joint surface involved?
Is the UCL unstable?
Is advanced imaging necessary? 35
Ultrasound
MRI
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FIGURE 80.7 Thumb MCP anatomy. Note that the proper collateral ligament (P) is tight in 30° of flexion, while the accessory
collateral (A) is tight in full extension. This is why when testing for a collateral ligament injury one must check the joint fully
extended and flexed to 30°. This relationship is the same for finger PIP collateral ligaments.
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FIGURE 80.8 Stener lesion. A. X-ray of a thumb with instability and pain on testing of the ulnar collateral ligament. Note the
small fracture fragment proximal to the joint line (red arrow). B. MRI of the same thumb with avulsed ulnar collateral ligament
(yellow arrow) retracted proximal to the adductor aponeurosis (blue arrow).
If a complete UCL tear is diagnosed (aka Skier’s thumb), open repair of the ligament is warranted. 36
These injuries usually involve detachment off of the distal site, but proximal tears and midsubstance tears
do occur as well. Small minimally displaced (<2 mm) avulsion fractures can be treated conservatively,
similar to partial tears. Larger or displaced fractures likely require open reduction and fixation; however,
advanced imaging may be warranted to clarify whether a UCL injury has also occurred, as the
examination may not be adequate for diagnosis of the combined bony and ligamentous injury. Stener
lesions require operative intervention.
Operative approach is via a lazy-S incision over the ulnar border of the thumb, taking care not to violate
the webspace with the incision. Midsubstance tears can be primarily repaired with permanent suture,
whereas ligament avulsions are treated with bone anchors. If the distal avulsion donor site is not clear,
aim to affix the ligament 3 mm distal to the articular surface and 3 mm dorsal to the volar cortex. If the
avulsion is off of the metacarpal, aim to anchor at or dorsal to bony midline. Most surgeons advocate
holding the tMCPJ in ulnar deviation and passing a K-wire across the joint to stabilize it during the acute
recovery period.
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Chronic Thumb MCPJ UCL Injuries (aka Gamekeeper’s Thumb)
This injury presents as symptomatic chronic UCL pain and laxity. This can occur due to chronic overuse
(i.e., game keepers) or, more commonly, inadequately treated acute UCL injuries. Confirm that there is no
substantial tMCPJ arthritis before attempting to reconstruct the joint—if there is, fusion may be the
proper treatment. If there is no arthritis, surgical repair with anchoring of the UCL can be attempted 37 ;
however, often the ligament is scarred and contracted, and a formal reconstruction is required to stabilize
the joint. 38
Static reconstruction options are most commonly used, involving harvesting a free tendon graft and
using it to recreate the ligament via bone tunnels and tenodesis screw fixation.
Dynamic reconstruction options include transfer of adductor pollicis or extensor pollicis brevis
insertion to the base of the proximal phalanx to create ulnar pull.
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Thumb MCPJ Radial Collateral Ligament Injuries
RCL injuries are more likely to occur from an axial load force and often present later than UCL injuries
because RCL instability is not as functionally limiting as UCL instability. Also, in contrast to the UCL, the
RCL most commonly ruptures off of the proximal attachment. Additionally, the abductor pollicis brevis
inserts more distally on the radial side, covering the RCL and generally preventing a Stener-type lesion.
39,40 One case report presents an exception. 41
Presentation is similar to UCL injuries, with pain and edema along the radial side of the tMCPJ. The
examination should be the same as with UCL injuries, evaluating degree of angulation on joint stressing
along with other details reviewed above. Because the radial-sided structures contribute more to dorsal
joint stability, also check for palmar subluxation when evaluating RCL injuries, as 3 mm or more of
palmar subluxation is an indication of a complete tear.
Partial injuries should be treated conservatively with thumb spica splinting and IP left free. Management
of a complete tear is controversial. Because a Stener-type lesion does not occur with RCL injury, some
advocate splinting/casting similar to partial injuries. However, concern that thenar muscle ulnar
deviation force is too strong to oppose with splinting has led others to advocate surgical repair of
complete tears. If surgical repair of an acute tear is pursued, recommendations include fixating the joint
in 30° of flexion with a K-wire, so the ligament repair is done on maximal tension and the adductor
pollicis pull is prevented. Chronic injuries likely require ligament reconstruction.
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Thumb MCPJ Dislocations
Most tMCPJ dislocations are dorsal, often the result of hyperextension that ruptures the volar plate, joint
capsule, and at least part of the collateral ligaments.
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