The basal joint of the thumb is exposed through a modified Wagner incision. There is a longitudinal component parallel to the long axis of the thumb metacarpal located in the interval between the glabrous palmar and nonglabrous dorsal skin. The incision is continued transversely in the wrist crease to just ulnar to the FCR tendon (Fig. 1). There is invariably a branch of the dorsal sensory branch of the radial nerve crossing the operative field that should be mobilized and protected throughout the procedure.
The radial edge of the thenar musculature at its insertion on the thumb metacarpal is identified
and the muscle elevated extraperiosteally from the thumb metacarpal, thus exposing the metacarpal base, CMC joint, and trapezium. Most patients undergoing volar ligament reconstruction have normal-appearing CMC joints on radiograph and are symptomatically lax. There is usually no crepitus with motion of the CMC joint. In that situation, it is unnecessary to visualize the CMC joint. If, however, there is any question about the condition of the articular cartilage, a transverse arthrotomy can be made and the joint inspected. The arthrotomy should be closed after exploration.
The skin flaps are elevated sufficiently far dorsally to visualize the dorsum of the metacarpal base. The interval between the extensor pollicis longus (EPL) and EPB tendons is developed, and the dorsal cortex exposed. A hole is made in the base of the thumb metacarpal from dorsal to volar, parallel and approximately 1.0 cm distal to the articular surface. The hole is begun in a plane perpendicular to the axis of the thumbnail, and is made with handheld gouges (Fig. 2). There are three sizes of gouge with progressively larger radii of curvature of the cutting end. The small gouge is carefully driven through the metacarpal base to emerge volarly just distal to the normal insertion of the volar (anterior oblique) ligament. The hole is enlarged with the medium and large gouges sequentially. A 28-gauge stainless steel wire is placed through the hole from volar to dorsal, using the concavity of the gouge as a guide for passage (Fig. 3). The two ends of the wire are clamped in a hemostat.
Attention is then directed to harvesting a slip of the FCR tendon. The sheath of the FCR tendon is identified in the transverse limb of the surgical incision at the level of the wrist crease.
The tendon sheath is opened proximally and distally for approximately 1 cm in each direction. The traditional way to harvest the FCR tendon is through multiple short transverse incisions on the volar forearm, between the incision at the wrist and the level of the musculotendinous junction of the tendon. After it is mobilized proximally, the slip of the FCR tendon is dissected and passed from proximal to distal beneath the skin bridges between the incisions.
It is possible to harvest the slip of FCR through the transverse limb of the incision at the wrist crease and only one incision in the forearm at the musculotendinous junction (Fig. 4). To accomplish this, the plane between the subcutaneous tissue and the FCR tendon sheath is developed. The tendon sheath is incised longitudinally under direct vision proximally and distally. The tendon is mobilized at the musculotendinous junction and delivered into the wound. The tendon is split longitudinally in approximately the midline. The fibers of the FCR spiral, so the fibers that begin
ulnarly terminate radially, and it is this part of the tendon that should be mobilized. Therefore, the ulnar half of the tendon is transected and dissected distally for a few centimeters. The tendon is split longitudinally with a heavy suture placed into the split between the halves of the tendon. To deliver that suture into the forearm wound, the suture must be drawn from the distal incision proximally. A 28-gauge stainless steel wire is bent in half. The apex of the bend is placed into a skin hook and the wire twisted, leaving a small loop on the end. This wire is semirigid, which facilitates its passage. It is placed in the forearm wound and carefully threaded in the subfascial plane toward the wrist along the course of the FCR tendon (Fig. 5). The looped end of the wire is passed into the transverse limb of the Wagner incision, and a 0-prolene suture is placed through the loop and folded onto itself. The two ends of the suture are held in a hemostat at the wrist, and the folded end is drawn into the forearm incision.
The loop of the wire is cut and the wire removed. The folded prolene suture is then placed in the crotch of the split FCR tendon (Fig. 6). The divided end of the tendon is held with the hemostat and the suture is pulled from proximal to distal into the wrist incision, splitting the tendon along its fibers (Fig. 7).
The split in the tendon is further developed distal to the level of the bercle of the trapezium. The end of the FCR tendon slip is secured in a knotted loop of the volar end of the stainless steel wire, previously placed in the hole in the metacarpal base. Using the wire for traction, the tendon graft is delivered through the hole from volar to dorsal. The thumb is reduced in a position of extension and abduction. Tension is set on the tendon by pulling it firmly, and then allowing it to retract 2 or 3 mm as the tension is relaxed. The FCR segment is sutured to the periosteum adjacent to the hole in the dorsal cortex of the metacarpal, using figure-of-eight or mattress sutures of 3-0 braided synthetic suture such as ethibond (Fig. 8). The tendon is placed beneath the APL tendon to which it is sutured (Fig. 9). It is directed volarly, where it is looped around the intact FCR tendon, to which it is also sutured (Fig. 10). Any remaining length of tendon is redirected dorsally, where it is passed beneath and sutured to the abductor pollicis longus tendon.
The stability of the CMC joint should be assessed before closure. The reconstruction is secure, and it is not necessary to transfix the CMC joint with a Kirschner wire, although there is little harm in doing so if it provides the operator an additional sense of security. The thenar musculature is reapproximated with interrupted sutures of 4-0 PDS or vicryl. The skin is closed with
interrupted sutures of 5-0 plain or vicryl rapide, which obviates the need for a cast change to remove sutures. The thumb is immobilized in a short arm-thumb spica cast for a period of 4 weeks, after which it may be immobilized part time in a thumb stabilizer splint, which is removed for range-of-motion exercise.
Several key steps of the procedure are shown in illustrations done by one of the creators of the procedure, Dr. J. William Littler (Figs. 11 and 12) .
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