Paralytic Hand - Clinical Tree

Sensation, mobility, and strength are required for the highly adaptive functions of pinch, grasp, and hook. Positional changes and delicate movements also are made possible by the many joints of the 29 hand, wrist, and forearm bones and by the 50 muscles that act as motors and stabilizers. To be purposeful, motion must be controlled, and joints crossed by moving tendons must be stabilized by balanced antagonistic muscles.

The normal upper extremity can rhythmically position the hand through varied concerted extrinsic and intrinsic phasic muscle activity. Muscle activities are controlled at the unconscious and conscious level and become patterned by repetition. Some patterns of muscle group movement act in such endless coordinated repetition that they are said to be synergistic or working together ( Fig. 71.1 ). The wrist extensors, finger flexors, and digital adductors act together with ease and are synergistic; similarly, the wrist flexors, finger extensors, and digital abductors are synergistic. Beginning with the wrist flexed and the fingers extended and abducted, the wrist can be extended and the fingers can be flexed, and then the original position can be resumed with ease. With the wrist and fingers extended, however, flexing the wrist and fingers and then resuming the original position involves slower, more awkward movements that must be directed consciously.

When a major hand muscle is paralyzed, hand balance is disrupted. Unopposed antagonist muscle contraction often leads to fixed contractures. Although contractures may increase the stability of the hand, they usually increase its disability.

A common imbalance resulting in predictable contractures follows a low ulnar nerve paralysis leading to a clawhand deformity ( Fig. 71.2 ). Paralysis of the intrinsic metacarpophalangeal joint flexors and intrinsic interphalangeal joint extensors (interossei and lumbricals) leads to characteristic deformities of the fingers, wrist, and thumb. In clawhand the extrinsic digital extensors and flexors are unopposed. The metacarpophalangeal joints extend and the interphalangeal joints flex at the fingers. The wrist is pulled into flexion by the strong finger flexors, which, by a tenodesis effect, worsens the metacarpophalangeal joint hyperextension. Even the thumb may assume a typical deformity.

The extensor pollicis longus adducts the thumb as it is unopposed by the intrinsic muscles of opposition and abduction. This adducted position is accompanied by extension of the carpometacarpal joint and flexion of the interphalangeal joint.

The hand position just described is known as the intrinsic minus or clawhand deformity . Whether the loss of intrinsic function is caused by disease or trauma, the results of dynamic muscle imbalance are the same. Sensation in clawhand varies according to the cause of imbalance. In poliomyelitis, sensation is normal; in peripheral nerve lesions, sensory deficits depend on the nerve lesion and level; in Hansen disease, sensation is absent, sometimes in a glovelike distribution; and in syringomyelia, sensation is partly absent.

Muscle spasticity also can disrupt hand balance, and muscle tension may not be controlled and balanced effectively by the opposing normal muscles. Such a situation is sometimes seen in cases of cerebral palsy, and it can cause overstretching of muscles and dislocation of joints.

Principles of Tendon Transfer

Tendon transfers are useful in restoring hand and upper extremity functions. Some basic principles must be followed if transfers are to be successful and if an increase in imbalance and deformity is to be avoided. After these principles are discussed, some specific tendon transfers are suggested for patterns of functional loss.

Planning Tendon Transfer

Regardless of the cause of the imbalance (traumatic, congenital, infectious, or vascular) the extremity must be evaluated in terms of function lost, function retained, and function possible through reconstruction. Muscles to be transferred must be expendable and have sufficient strength and appropriate amplitude of excursion. Moreover, the muscle should be synergistic, have appropriate alignment, and perform one function. Ideal timing of tendon transfers should consider the condition of the soft tissue and the mobility of adjacent joints. Transfers are best performed after reaching favorable soft-tissue conditions (not in the context of severe swelling or scarring) and after restoring passive motion of adjacent joints. Sometimes it is helpful to list in one column functions that are needed and in an opposite column the muscles available for transfer. Transfers can be planned with more ease and accuracy by matching these columns.

Evaluating Muscles for Tendon Transfer

The two most important points in considering a muscle for transfer are its expendability and its strength. Restoring one major function, such as finger extension, is contraindicated if done at the expense of another major function, such as finger flexion. The strength of a muscle is graded from 0 to 5 as follows:

- 0, zero—no contraction
- 1, trace—palpable contraction only
- 2, poor—moves joint but not against gravity
- 3, fair—moves joint against gravity
- 4, good—moves joint against gravity and resistance
- 5, normal—normal strength

A muscle usually loses strength by one grade when transferred and should be good or normal if the transfer is to be satisfactory. In addition to expendability and strength, the synergy and the amplitude of excursion of its tendon should be considered. Rehabilitation of a muscle whose tendon has been transferred is less difficult when the transfer is synergistic (e.g., a wrist flexor transfer to restore finger extension). The amplitude of excursion of the tendon should be sufficient for satisfactory function, although it may not be as great as that of the tendon or tendons it is to replace. The brachioradialis, an expendable muscle for transfer, is capable of pulling its tendon through only a short excursion, but sometimes it can be useful, if not ideal, as a transfer to the long thumb flexor because even limited flexion of the interphalangeal joint of the thumb is useful.

The excursion of the brachioradialis can be increased by dissecting its tendon proximally and freeing all of its fascial attachments. The muscle is not useful as a transfer for finger flexion because its excursion cannot be increased enough.

Timing of Tendon Transfer

The transfer of tendons is the final step in rehabilitation of the hand. It should not be done until scar tissue has been satisfactorily replaced because transferred tendons must be surrounded by fat to prevent them from adhering to raw bone or subcutaneous scar; consequently, a flap or graft containing fat is necessary to replace scar. A satisfactory range of passive joint motion is also necessary before the transfer; proper splinting or ligamentous release is done as needed. Stiffness or contracture of joints cannot be corrected by tendon transfers alone; if left uncorrected, stiffness or contracture prevents a transferred tendon from moving at the proper time after surgery, so the tendon becomes permanently adherent to the surrounding tissues. Malalignment of bone must be corrected by osteotomy, and any necessary bone grafting must be accomplished before transfer. Necessary operations to restore any loss of sensibility should also precede tendon transfer.

In poliomyelitis, some recovery of muscle power can be expected until 18 months after the acute stage of the disease, and consequently this much time must pass before an accurate evaluation is possible; any further recovery cannot be expected to improve muscle strength more than one grade, if at all. During this waiting period, parts must be splinted properly to improve available muscle function and to prevent fixed deformity. In congenital anomalies, the relative muscle strength does not change. In syringomyelia, weakness may increase even after transfer. Peripheral nerve injuries must be considered individually; in division of the radial nerve at the midhumerus, transfers for finger and thumb extension and for thumb abduction should be delayed for 6 months or longer after neurorrhaphy. Certain nerve transfers also may be useful to restore function either alone or concomitantly with tendon transfers (see Chapter 62 ). Early transfer to restore wrist extension should be considered an internal splint for the wrist; this immediately improves the function of the hand. Transfer of the pronator teres to the extensor carpi radialis brevis is recommended. In high median nerve lesions, some function should return in the most proximal muscles in 4 months (3 months in low median nerve lesions); if it has not, the nerve should be explored, or tendon transfers should be considered.

Technical Considerations for Tendon Transfer

Although the strength of a muscle is evaluated clinically before surgery, its color at the time of tendon transfer provides a further check. A muscle suitable for transfer is dark pink or red, indicating satisfactory nutrition and the presence of normal muscle fibers. A weak or paralyzed muscle is pale pink and is smaller than normal, and its amplitude of excursion ( Table 71.1 ) is less than normal when tested at surgery; such a muscle is unsuitable for transfer ( Fig. 71.3 ). Muscles that do not contract with a stimulus (pinch or electrocautery) are probably nonfunctional and should not be chosen as active donor muscles.

TABLE 71.1

Amplitude of Excursion

From Curtis RM: Fundamental principles of tendon transfer, Orthop Clin North Am 2:231, 1974.

Tendons	Amplitude (mm)
Wrist tendons	33
Flexor profundus	70
Flexor sublimis	64
Extensor digitorum communis	50
Flexor pollicis longus	52
Extensor pollicis longus	58
Extensor pollicis brevis	28
Abductor pollicis longus	28

FIGURE 71.3, Power of muscle transfer. A, Working capacity of muscle. W = F × d, where F (force) = absolute muscle power, 3.65 × cm 2 of physiologic cross section, and d (distance) = amplitude or displacement. B, Working capacity of muscle in mkg (meter-kilograms). C, Muscle amplitude in millimeters.

A muscle that has been detached from its insertion some time before transfer will have developed a contracture, and consequently its tendon should be anchored under more tension than usual because it will stretch and regain some of its excursion. A muscle and its tendon should not make an acute angle between the origin of the muscle and the new attachment of the tendon—the straighter the muscle, the more efficient its action. If an acute angle is necessary, a pulley must be created, but efficiency of the muscle is diminished by friction at the pulley. In freeing a muscle for transfer, care must be taken to avoid stretching or otherwise damaging the neurovascular bundle, which usually enters the proximal third of the muscle belly. A transferred tendon cannot be expected to glide properly when it crosses raw bone, passes through fascia without a sufficient opening, or is buried within scarred tissue; with a few exceptions, transferred tendons should be passed subcutaneously. Should it be necessary to split a transferred tendon and anchor it to two or more separate points, the muscle acts primarily on the slip of tendon under greatest tension; great care must be taken to equalize tension on the slips at the time of attachment.

The more distal to a given joint a tendon is anchored, the more power the muscle can exert across the joint, but also the more excursion is required of the tendon to provide normal motion. The greater the angle of approach of a tendon to bone, the greater the force the muscle can exert on the bone and across the joint. Most muscles lie almost parallel to the bones whose joints they act on, and few approach a bone at close to a right angle; the pronator quadratus and the supinator are notable exceptions.

Restoration of Pinch

Restoration of Thumb Opposition

Thumb opposition is necessary for pinch. Frequently, opposition is either partially or totally lost in poliomyelitis or median nerve palsy. Opposition depends primarily on function of the thumb intrinsic muscles, especially the abductor pollicis brevis. Extrinsic muscles also are necessary to stabilize dynamically the thumb metacarpophalangeal and interphalangeal joints, or these joints must be stabilized by arthrodesis or tenodesis. At the same time, the thumb carpometacarpal joint must be freely movable, unrestricted by contracture of the joint capsule or other structures of the thumb web.

Thumb opposition is a complex motion made by coordination of (1) abduction of the thumb from the palmar surface of the index finger, (2) flexion of the metacarpophalangeal joint, (3) internal rotation or pronation, (4) radial deviation of the proximal phalanx, and (5) thumb motion toward the fingers (see Fig. 71.13 ). Although opposition is the result of coordinated function of all of the long and short muscles that act on the thumb, the abductor pollicis brevis is the most important single muscle that participates in this complex movement; it rotates internally and abducts the thumb away from the index metacarpal, internally rotates and abducts the proximal phalanx of the thumb on its metacarpal, and assists the extensor pollicis longus in extending the interphalangeal joint of the thumb. For these reasons, in restoring opposition by tendon transfer, the transferred tendon can be inserted into the tendon of the abductor pollicis brevis.

Correction of Thumb Deformity

To restore thumb function properly, deformities or disabilities of the digit other than those corrected by the operation designed primarily to restore opposition frequently must be corrected either before or during such surgery. As a substitute for opposition, adduction of the thumb by the long thumb extensor may have become a habit; in these instances, adduction and extension of the thumb occur as a single function in which the flexed tip of the thumb is brought against the base of the proximal phalanx of the index finger by the pull of the long thumb extensor toward Lister’s tubercle. Pinch occurs at the base of a finger instead of at its tip, and to pick up an object, the point of contact between the thumb and the finger must be rotated downward; this is accomplished by pronating the wrist, elevating the elbow, and abducting the shoulder. As the substitution patterns become more firmly established after paralysis of the intrinsic muscles of the thumb, the long thumb extensor tendon, acting as an adductor, gradually migrates into the web space between the thumb and index finger.

Any fixed adduction and external rotational deformity of the thumb must be corrected; this usually can be accomplished by dividing the fascia in the web space between the index and thumb metacarpals and by subperiosteal stripping of the ulnar side of the first metacarpal. If the deformity is severe, a Z-plasty of the web also may be required (see section on restoration of adduction of the thumb); if the deformity is so severe that it cannot be corrected by rotational osteotomy and release of the web space, arthrodesis of the first carpometacarpal joint may be indicated. A tendon transfer for opposition still may be useful after such an arthrodesis because the more proximal joints may allow some motion. If mobility is more desirable than stability, however, excising the trapezium may release the soft tissues enough to make arthrodesis unnecessary.

Tendon transfers to the long thumb flexor, long thumb extensor, or long thumb abductor may be necessary to stabilize the thumb dynamically if the transfer to restore opposition is to function satisfactorily. Arthrodesis of the metacarpophalangeal joint of the thumb may be necessary if available muscle power is insufficient to stabilize it dynamically, or if the joint is made unstable by relaxation of its ligaments or capsule. (Arthrodesis of this joint also may be indicated after tendon transfer to restore opposition when the tendon has been anchored in an incorrect location and hyperextends or hyperflexes the joint.) The joint is arthrodesed in 15 degrees of flexion and slight internal rotation to allow pinch between the thumb and index fingertip. Arthrodesis of the thumb interphalangeal joint is indicated occasionally for a fixed flexion contracture; it is arthrodesed in 20 degrees of flexion.

Tendon Transfers to Restore Opposition

Multiple tendon transfer techniques to restore elongated pinch in paralytic hands have been devised. Common to all techniques is the selection of one extrinsic, expendable, healthy muscle-tendon unit motor and its transfer to a suitable point and angle to pull the thumb into opposition. The direction in which the transferred tendon approaches the thumb usually has been from the ulnar side of the wrist or palm; sometimes the tendon has been brought around a pulley to provide this direction. A pulley often is needed, and some authors prefer a static pulley created by making a loop at the distal end of the flexor carpi ulnaris tendon, whereas others prefer a dynamic pulley formed by looping the transfer around this tendon.

A proper muscle for a motor is selected after carefully evaluating the strength of available units. The ring finger flexor digitorum sublimis usually is the muscle of choice and often is used if it is strong enough to function as the transfer and if its associated flexor digitorum profundus is strong enough alone to flex the finger satisfactorily; the second choice is the sublimis to the middle finger. If the preferred flexor tendons of the digits are unsuitable for transfer, the extensor indicis proprius is an acceptable alternative. All other muscles require tendon grafting to reach the point of attachment on the thumb. The extensor carpi ulnaris is the next choice, followed by the palmaris longus or extensor carpi radialis longus. A wrist extensor should be transferred, however, only if the other wrist extensors are strong and have not been or will not be transferred elsewhere.

Transfer of the Sublimis Tendon

Technique 71.1

(RIORDAN)

▪
Expose the ring finger sublimis tendon through an ulnar midlateral incision over the proximal interphalangeal joint and divide the tendon at the level of the joint or just proximal to it.
▪
Divide the chiasm, separating the two slips of tendon at the level of the joint so that they pass around the profundus and can be withdrawn easily at the wrist.
▪
Expose the flexor carpi ulnaris tendon through an L-shaped incision that proximally extends along the flexor carpi ulnaris tendon and distally turns radialward parallel to the flexor creases of the wrist. To make a pulley, cut halfway through the flexor carpi ulnaris tendon at a point approximately 6.0 cm proximal to the pisiform ( Fig. 71.4 ).
▪
Strip the radial half of the tendon distally almost to the pisiform and create a loop large enough for the sublimis tendon to pass through easily; carry the radial segment of the flexor carpi ulnaris through a split in the remaining half of the tendon, loop it back, and suture it to the remaining half.
▪
Make a wide C-shaped incision on the thumb as follows: Begin on the thumb dorsum just proximal to the interphalangeal joint and proceed proximally and volarward around to the radial aspect of the thumb. At a point just proximal to the metacarpophalangeal joint, curve the incision dorsalward in line with the major skin creases of the thenar eminence. On the dorsoradial aspect of the thumb, preserve the fine sensory nerve from the superficial branch of the radial nerve. Expose and define the extensor pollicis longus tendon over the proximal phalanx, the extensor aponeurosis over the metacarpophalangeal joint, and the abductor pollicis brevis tendon.
▪
At the wrist, identify the ring finger sublimis tendon and withdraw it into the forearm incision. Pass the tendon through the loop fashioned from the flexor carpi ulnaris.
▪
With a small hemostat or preferably a tendon carrier, pass the tendon subcutaneously across the thenar eminence in line with the fibers of the abductor pollicis brevis.
▪
Make a small tunnel for insertion of the transfer by burrowing between two small parallel incisions in the abductor pollicis brevis tendon.
▪
Split the end of the sublimis tendon for approximately 2.5 cm, or more if necessary, and pass one half of it through the tunnel.
▪
Separate the extensor aponeurosis from the thumb proximal phalanx periosteum, make a small incision in it 6 mm distal to the first tunnel, and pass the same strip of sublimis through it. Bring the slip out from beneath the aponeurosis through a small longitudinal slit in the long extensor tendon about 3 mm proximal to the interphalangeal joint.
▪
Determine the proper tension for the transfer. Grasp the two slips of sublimis with small hemostats and cross them. With the thumb in full opposition and the wrist in a straight line, place the two overlapping slips of sublimis under some tension. Releasing the thumb and passively flexing the wrist should completely relax the transfer so that the thumb can be brought into full extension and abduction; extending the wrist 45 degrees should place enough tension on the transfer to bring the thumb into complete opposition and the tip of the thumb into complete extension.
▪
If the tension is insufficient, increase it and repeat the test.
▪
When the correct tension has been determined, suture the slips of sublimis together with the cut ends buried ( Fig. 71.4 ).
▪
Anchor the transfer and the tendon of the abductor pollicis brevis to the joint capsule with a single nylon or wire suture so that the transfer passes over the middle of the metacarpal head; this prevents later displacement of the tendon toward the palmar aspect of the joint during opposition.
▪
Close the wound with nonabsorbable sutures and immobilize the hand in a pressure dressing and a dorsal plaster splint as follows: place the wrist in 30 degrees of flexion, the fingers in the functional position, and the thumb in full opposition with the distal phalanx extended; place a few layers of gauze between the individual fingers to prevent maceration of the skin.

Postoperative Care

At 4 weeks, the dressing and splint are removed and active motion is begun, but the thumb is supported with an opponens splint for an additional 6 weeks. Many patients can oppose the thumb as soon as the splint is removed. When the ring finger sublimis has been used for the transfer, as in the Riordan technique, training in its use can be facilitated by asking the patient to place the tip of the thumb against the ring finger; this maneuver produces flexion of the ring finger and an automatic attempt to oppose the thumb with the transferred sublimis. In patients with weak quadriceps muscles who habitually rise from a sitting position by pushing up with the flattened hands or in patients who use crutches, the transfer must be protected for 3 months or longer or it will be overstretched and cease to function.

Transfer of the Sublimis Tendon

Technique 71.2

(BRAND)

▪
Expose and divide the ring finger sublimis tendon and make the incision over the thumb as just described in the Riordan technique.
▪
Withdraw the sublimis tendon through a small transverse incision about 5 cm proximal to the flexor crease of the wrist.
▪
Make a small longitudinal incision just to the radial side of and about 6 mm distal to the pisiform. Deepen this incision until the quality of fat changes from the fibrous superficial type to a soft, loose, free type that bulges into the wound. This change in the fat marks the entry into a tunnel that runs proximally and contains a branch of the ulnar nerve.
▪
In this loose fat, make a tunnel in the proximal direction to the forearm incision, grasp the end of the sublimis tendon, and pull it through into the palmar incision. The tunnel is superficial to the hook of the hamate, and the fibrous septa in the fat compose the pulley.
▪
Pass the tendon to the thumb metacarpophalangeal joint and attach it proximal and distal to the joint after splitting its end; attach the proximal slip of the tendon to the ulnar side of the joint and the distal slip to the tendons of the abductor pollicis brevis and the extensor pollicis longus ( Fig. 71.5 ). This dual insertion of the tendon may prevent the tendon from shifting in position as it crosses the metacarpophalangeal joint. (If an unsplit tendon shifts dorsally over the metacarpophalangeal joint, it is likely to hyperextend the joint; if it shifts anteriorly from the radial side of the joint, it is likely to flex the joint.)

Postoperative Care

Postoperative care is similar to that described after the Riordan technique (see Technique 71.1).

If the ring or long finger sublimis is unsuitable for transfer, the extensor indicis proprius can be rerouted around the ulnar aspect of the wrist to provide opposition, as described by Burkhalter et al. (see Technique 71.3). For high median nerve palsy or brachial plexus paralysis, a technique described by Groves and Goldner (see Technique 71.4) employing the flexor carpi ulnaris as a motor for a transferred sublimis tendon unit can be used.

Transfer of the Extensor Indicis Proprius

Technique 71.3

(BURKHALTER ET AL.)

▪
Through a short, curved incision on the radial side of the dorsum of the index metacarpophalangeal joint, identify the extensor indicis proprius tendon.
▪
Divide its insertion and a small portion of the extensor hood by sharp dissection and repair the hood with interrupted suture ( Fig. 71.6A ).
▪
If necessary, make a short incision over the midportion of the dorsum of the hand to withdraw the extensor tendon.
▪
Make a longitudinal incision about 2 cm long proximal to the wrist crease on the ulnar aspect of the forearm, and through it extract the tendon ( Fig. 71.6B ).
▪
Cut the fascia as necessary to reroute the muscle.
▪
Make another small incision in the area of the pisiform bone and pass through it the tendon unit, creating a gradual curve from the dorsum of the forearm to this point. From the pisiform area, pass the tendon unit subcutaneously to the tendinous portion of the abductor pollicis brevis just proximal to the metacarpophalangeal joint ( Fig. 71.7A ).
▪
Make another incision over the palmar side of the radial aspect of the metacarpophalangeal joint to expose the site of attachment.
▪
At this distal insertion, employ the technique of Riordan by splitting the tendon, or simply pass it into the tendinous portion of the abductor pollicis brevis and suture it with several interrupted sutures ( Fig. 71.7B ).
▪
Suture the tendon under maximal tension with the thumb in full abduction but with the wrist in only slight volar flexion.

Postoperative Care

Postoperative care consists of maintaining the wrist in flexion with a splint for a minimum of 4 weeks.

Transfer of the Flexor Carpi Ulnaris Combined with the Sublimis Tendon

Technique 71.4

(GROVES AND GOLDNER)

▪
Make volar and ulnar incisions at the wrist as shown in Figure 71.8A –C. The volar incision exposes the flexor sublimis tendon to the ring finger and the flexor carpi ulnaris, and the ulnar incision exposes the extensor carpi ulnaris.
▪
Divide the ring finger sublimis tendon insertion from the middle phalanx and bring it out at the wrist.
▪
Sever the flexor carpi ulnaris tendon, leaving a distal segment of this tendon sufficiently long to bring around the extensor carpi ulnaris tendon to create a pulley.
▪
Pass the sublimis tendon through this pulley and continue it subcutaneously to the proximal end of the proximal phalanx of the thumb. Insert one split portion of this tendon into the bone with a pull-out wire and another into the bone by direct attachment ( Fig. 71.8D ).
▪
Suture the proximal functioning segment of the flexor carpi ulnaris and its tendon into the sublimis tendon unit under sufficient tension that dorsiflexion of the wrist provides full thumb opposition ( Fig. 71.8E ).

Transfer of the Palmaris Longus Tendon to Enhance Opposition of the Thumb

Transfer of the palmaris longus tendon to enhance opposition of the thumb has been recommended if the abductor pollicis brevis has weakened and atrophied from a partial median nerve palsy, which may accompany severe carpal tunnel syndrome. An advantage of the operation is its close proximity to the median nerve, which may require repair or release that can be done at the same time without much additional surgery. It does not produce true opposition but rather elevates the thumb toward the flexed and abducted position. Presence of a palmaris longus must be confirmed before this procedure. This transfer is not a viable option for high median nerve palsies.

Technique 71.5

(CAMITZ)

▪
Make a curved incision parallel to the base of the thenar crease and extend it proximally 4 cm up the forearm.
▪
Isolate the palmaris longus tendon in the distal forearm and preserve its insertion on the deep palmar fascia.
▪
Dissect the palmar fascia fibers in continuity with the palmaris longus tendon to obtain a strip of fascia long enough to reach the distal part of the abductor pollicis brevis tendon.
▪
Pass the lengthened tendon into a small skin incision made over the thumb metacarpal and suture it to the tendon of the abductor pollicis brevis under appropriate tension with the thumb in full opposition and the wrist in neutral position.

Muscle Transfer (Abductor Digiti Quinti) to Restore Opposition

If other motors are unavailable or must be transferred elsewhere, the abductor digiti quinti muscle can be utilized to restore opposition. Such transfer has been described by Huber and by Littler and Cooley as presented here. Because its mass and excursion are similar to those of the abductor pollicis brevis, this muscle is an excellent substitute for it. Cosmetically, the transfer is helpful because it fills the space left by the wasted thenar muscles. It does not require a pulley.

Technique 71.6

(LITTLER AND COOLEY)

▪
Make a curved palmar incision along the radial border of the abductor digiti quinti muscle belly extending from the proximal side of the pisiform proximally to the ulnar border of the little finger distally ( Fig. 71.9A ).
▪
Free both tendinous insertions of the muscle, one from the extensor expansion and the other from the base of the proximal phalanx.
▪
Lift the muscle from its fascial compartment and carefully expose its neurovascular bundle. Isolate the bundle, taking care not to damage the veins.
▪
Free the origin of the muscle from the pisiform, but retain the origin on the flexor carpi ulnaris tendon; now the muscle can be mobilized enough for its insertion to reach the thumb ( Fig. 71.9B ).
▪
Make a curved incision on the radial border of the thenar eminence and create across the palm a subcutaneous pocket to receive the transfer.
▪
Fold the abductor digiti quinti muscle over about 170 degrees (like a page of a book) and pass it subcutaneously to the thumb ( Fig. 71.9C ).
▪
Suture its tendons of insertion to the abductor pollicis brevis insertion. Throughout the procedure, avoid compression of and undue tension on the muscle and its neurovascular pedicle.
▪
Apply a carefully formed light compression dressing and a volar plaster splint to hold the thumb in abduction and the wrist in slight flexion.

Restoration of Adduction of the Thumb

Strong pinch requires both thumb opposition and adduction. Opposition is the refined, unique movement that positions the thumb so that its tip can oppose the fingertips throughout their flexion arcs. Once the tips are opposed, especially that of the thumb and index finger, thumb adduction force is necessary for performing work activities. If the adductor pollicis is paralyzed, as in ulnar nerve palsy, firm index and middle finger pinch is impossible, and the thumb cannot be brought across the palm for pinch with the ring and little fingers. The flexor pollicis longus can provide some adduction power when the thumb is held in slight adduction so that the muscle flexes the digit through an arc parallel to the plane of the palm. Eventually, the interphalangeal joint of the thumb becomes hyperflexed as the flexor pollicis longus attempts to produce pulp pinch (Froment sign) and the metacarpophalangeal joint becomes hyperextended secondary to unbalanced extensor forces (Jeanne sign) ( Fig. 71.10 ).

Several transfers have been devised to restore adduction. If adduction alone is absent, the brachioradialis or one of the radial wrist extensors can be lengthened by a graft, transferred palmarward through the third interosseous space, and carried across the palm to the tendon of the adductor pollicis. Such a transfer provides adduction only and this in the direction normally provided by the adductor pollicis. It is most often indicated in ulnar nerve palsy because in this instance restoring thumb abduction is unnecessary; however, it should be combined with some procedure to restore index finger abduction. If adduction and opposition of the thumb are absent, unless some other provision is made to restore adduction, a single tendon transfer to restore opposition should have its pulley located not near the pisiform, but more distally so that some adduction also is restored. One technique meeting this requirement is the Royle-Thompson transfer in which the ring finger flexor digitorum sublimis is carried across the palm and anchored to the adductor pollicis tendon and the transverse carpal ligament serves as a pulley. To restore abduction of the index finger and adduction of the thumb, the sublimis tendon can be split and one slip anchored to the tendon of the adductor pollicis and the other to the insertion of the first dorsal interosseous.

Opposition is only partially restored by Royle-Thompson transfer, and thumb metacarpophalangeal abduction and pronation remain limited. An alternative adductorplasty to correct these deficiencies was described by Brand in which the ring finger sublimis is used as a motor ( Fig. 71.11 ). It traverses the palm superficially and is inserted on the radial aspect of the thumb. The sublimis is sectioned at the proximal phalanx through a short incision and is brought out at the midpalm just ulnar to the thenar crease. This tendon is passed through the natural openings of the fascia between the ring and long fingers at the distal third of the palm. It is passed subcutaneously to be inserted radial and distal to the metacarpophalangeal joint, which pronates the thumb and restores adduction power.

Transfer of the Brachioradialis or Radial Wrist Extensor to Restore Thumb Adduction

Technique 71.7

(BOYES)

▪
Detach the brachioradialis tendon at its radial styloid insertion and carefully free the tendon proximally of all fascial attachments to increase its excursion.
▪
Anchor a tendon graft (plantaris or palmaris longus) to the adductor tubercle of the thumb by a pull-out wire, or suture the graft to the tendon of insertion of the adductor pollicis.
▪
Pass the graft along the adductor muscle belly and through the third interosseous space to the dorsum of the hand ( Fig. 71.12 ).
▪
Pass it subcutaneously in a proximal and radial direction and suture it to the end of the brachioradialis tendon. If a radial wrist extensor is used, pass the tendon graft deep to the extensor digitorum communis tendons and attach it to the wrist extensor. The tension should be set maximally with the thumb in radial and palmar abduction and the wrist in neutral position.
▪
Apply a plaster splint while holding the thumb in adduction and the wrist in extension.

Postoperative Care

At 4 weeks, the splint is removed and active exercises are begun with a removable protective forearm-based thumb spica preventing thumb hyperextension for the next 2 weeks.

Transfer of the Extensor Carpi Radialis Brevis Tendon to Restore Thumb Adduction

Smith described transfer of the extensor carpi radialis brevis tendon to provide strong thumb adduction. To extend the tendon, he used a tendon graft and passed it through the second interosseous space. On average, pinch was reported to have doubled in strength after the transfer ( Figs. 71.13 and 71.14 ).

Technique 71.8

(SMITH)

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Make two dorsal transverse incisions over the extensor carpi radialis brevis tendon proximal to its insertion ( Fig. 71.14A ).
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Divide the tendon near its insertion on the third metacarpal base and withdraw it through the incision proximal to the dorsal retinaculum ( Fig. 71.14B ).
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Make a third incision between the second and third metacarpals and remove a window of tissue from the paralyzed interosseous muscles.
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Make a longitudinal incision on the ulnar side of the metacarpophalangeal joint of the thumb.
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With a curved hemostat, tunnel deep to the adductor pollicis muscle and through the window in the second interosseous space. Secure an appropriate tendon graft (usually the palmaris longus tendon).
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Draw the graft through the tunnel from the thumb to the dorsum of the hand ( Fig. 71.14C ) and suture it to the tendon of the adductor pollicis ( Fig. 71.14D ).
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Pass the proximal end of the graft subcutaneously to the most proximal incision ( Fig. 71.14E ) and suture it to the extensor carpi radialis brevis tendon, taking up all slack but with no tension so that the thumb lies just palmar to the index finger with the wrist in neutral position ( Fig. 71.14F ).
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Dorsiflex the wrist and note that the thumb is pulled into adduction. Flex the wrist and note that the thumb lies firmly against the palm.

Postoperative Care

The hand is immobilized in a cast with the thumb in neutral position and the wrist in 40 degrees of dorsiflexion. The cast is removed in 4 weeks, and active motion is encouraged.

FIGURE 71.13, Adduction and abduction of thumb are in plane perpendicular to palm. Flexion and extension of thumb are in palmar plane. Pronation and supination are rotation of thumb around its longitudinal axis. Opposition is complex of abduction, flexion, and pronation of first metacarpal (and flexion and abduction of proximal phalanx and extension of distal phalanx).

FIGURE 71.14, Smith transfer of extensor carpi radialis brevis tendon. A, Usual incisions ( A and B ) for detaching and withdrawing extensor carpi radialis brevis, channeling tendon graft through second interspace (C) , and attaching graft to tendon of adductor pollicis (D) . B, Extensor carpi radialis brevis is transected distally and withdrawn proximal to dorsal retinacular ligament (“sheath”). C, Tendon graft (palmaris longus or plantaris) is passed deep to adductor pollicis and between second and third metacarpals. D, Tendon graft is sutured to adductor tendon. E, Proximal end of tendon graft is passed subcutaneously to proximal incision. F, Tendon graft sutured proximally to extensor carpi radialis brevis with thumb adducted and wrist at 0 degrees of extension. Extensor carpi radialis brevis is at resting length. Graft is made slightly longer if thenars are paralyzed.

Royle-Thompson Transfer (Modified)

Technique 71.9

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Make a midlateral incision over the ulnar aspect of the ring finger and free the insertion of the flexor digitorum sublimis tendon ( Fig. 71.15 ).
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Bring the tendon out of the palm through a short transverse incision and split it into two slips.
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Make a curved incision on the dorsoradial aspect of the thumb as described earlier for the Riordan transfer (see Technique 71.1). Tunnel the slips of the sublimis tendon radially into this incision.
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Suture one slip to the extensor pollicis longus tendon distal to the metacarpophalangeal joint; tunnel the other slip dorsally over the metacarpal, and suture it on the ulnar side of the thumb to the tendon of insertion of the adductor pollicis.
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Close the wounds and apply a forearm-based thumb splint holding the thumb in adduction and the wrist in moderate flexion.

Postoperative Care

At 4 weeks, the splint is removed and active exercises are begun with a removable protective forearm-based thumb spica preventing thumb hyperextension for the next 2 weeks.

Restoration of Abduction of the Index Finger

The index finger is against which the thumb is brought most frequently in pinch. Strong index finger-thumb pinch relies on stability of the index finger metacarpophalangeal joint. Abduction of the index finger also is especially useful in such activities as playing a piano or using a typewriter or keyboard. In poliomyelitis, abduction of the index finger is lost so frequently that its restoration is considered here separately from that of the intrinsic functions of the other fingers.

A transfer to restore index finger abduction is a substitute chiefly for the first dorsal interosseous muscle and, therefore, the transferred tendon is attached to the first dorsal interosseous tendon insertion, which is primarily on the radial base of the index proximal phalanx. The tendons most frequently transferred are those of the extensor indicis proprius, extensor pollicis brevis, and palmaris longus; any of these when transferred abducts the index finger but does not stabilize it for strong pinch. A sublimis tendon also has been used, but this generally is contraindicated unless the hand is otherwise strong. If thumb opposition also must be restored, the sublimis to the ring finger often is used for this transfer (see Techniques 71.1 and 71.2).

Transfer of the Extensor Indicis Proprius Tendon

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