63: Trapeziometacarpal Fusion

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Procedure 63 Trapeziometacarpal Fusion

Nathan S. Taylor, Kevin C. Chung

See Video 47: Fusion of Thumb Carpometacarpal Joint

Indications

Posttraumatic degenerative osteoarthritis of the trapeziometacarpal (TMC) joint in manual workers who require great stability of the carpometacarpal (CMC) joint, which may not be achieved with trapezium excision and ligament reconstruction

Patients with substantial joint laxity and severe thumb CMC joint deformity that cannot be treated with soft tissue reconstruction alone

The case presented subsequently is such a situation in a patient with lupus in which the ligaments are so lax and the thumb deformity so severe that thumb CMC fusion will provide a stable platform to achieve proper thumb posture and stability.

Examination/Imaging

Clinical Examination

The patient’s thumb should be evaluated for tenderness along the TMC joint.

The grind test is performed with axial compression, flexion, extension, and circumduction of the TMC joint, which should elicit crepitus and pain.

The patient’s thumb metacarpophalangeal (MCP) joint should be assessed during pinch for hyperextensibility that can be corrected with MCP joint capsulodesis.

The Allen test should be performed because the procedure typically requires mobilization of and potential injury to the radial artery.

Imaging

Posteroanterior, oblique, and lateral radiographs of the hand should be obtained to evaluate extent of arthritis, osteophyte formation, and joint subluxation. Figure 63-1A and B demonstrates severe ligamentous laxity and subluxation of the TMC joint.

FIGURE 63-1

Surgical Anatomy

The TMC joint is a biconcave saddle-shaped joint that provides motion in several planes to allow thumb flexion, extension, abduction, adduction, and opposition.

The volar oblique (beak) ligament inserts volarly onto the trapezium from its confluence with articular cartilage on the beak of the thumb metacarpal and is considered the primary stabilizer of the TMC joint. It serves as the main restraint against dorsal translation of the metacarpal on the trapezium, and laxity of the beak ligament increases the risk for degenerative changes seen in the CMC joint due to loss of joint stabilization.

The radial artery traverses the anatomic snuffbox and overlies the dorsal capsule of the CMC joint.

The abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons are within the first extensor compartment.

The radial sensory nerve becomes subcutaneous after exiting through the interval between the brachioradialis and extensor carpi radialis longus (ECRL) muscles.

Positioning

The procedure is performed under tourniquet control with the patient in the supine position and the extremity abducted with the hand on a hand table.

Exposures

A 4-cm dorsal longitudinal incision overlying the TMC joint is made in the interval between the extensor pollicis longus (EPL) and EPB tendons to the level of the dorsal joint capsule (Fig. 63-2). The EPL tendon and radial artery should be retracted to expose the joint capsule.

FIGURE 63-2

Pearls

The radial sensory nerve branches are found within the subcutaneous tissue and should be protected. The radial artery is found in the interval between the EPL and EPB tendons deep to the subcutaneous fat and should be protected.

Procedure

Step 1

Incise the TMC joint capsule followed by the periosteum longitudinally, and sharply elevate radial and ulnar periosteal flaps off the metacarpal and trapezium for later coverage of the implant (Fig. 63-3).

FIGURE 63-3

Step 2

Resect the articular cartilage and subchondral bone between the trapezium and metacarpal using a rongeur.

Step 2 Pearls

Longitudinal traction applied to the thumb helps expose the joint surfaces for articular resection.

Step 3

A 2.3-mm locking T-plate is applied for arthrodesis. The locking plate is particularly helpful for fusion of this joint because the trapezium may be devoid of strong cortical bone for secure screw purchase in the traditional plating system, which relies on the friction between the screw and the bone for stability. The locking plate system locks the screw to the plate, which adds additional stability to the fusion site. After confirming that the plate is in the center of the metacarpal and that the T portion is centered on the trapezium, a locking screw is placed to secure the plate to the metacarpal. The remaining screws are placed in a locking fashion to provide stable fixation.

Step 3 Pearls

Intraoperative fluoroscopy is useful to confirm proper implant placement and screw fixation.

Cancellous bone graft (autologous or cadaveric) placed within any gaps can help augment bony union.

Step 4

The thumb is fixed in a position of function, typically 30 degrees of palmar abduction and 15 degrees of radial abduction (Fig. 63-4A and B).

FIGURE 63-4

Step 5

The periosteal flaps and joint capsule are closed in layers over the implant using 4-0 absorbable braided suture. The tourniquet is released, and all bleeding points are cauterized. Skin is closed using 4-0 permanent monofilament horizontal mattress sutures, and the hand is placed in a thumb spica splint (Fig. 63-5).

FIGURE 63-5

Postoperative Care and Expected Outcomes

Because of the potential for nonunion, the patient’s thumb remains immobilized in a thumb spica splint for 6 weeks to allow bony fusion. After 6 weeks, the patient begins gentle active range-of-motion exercises.

Expected outcomes include improved pain relief and improved hand function with insignificant change in strength despite loss of motion. Patients should be expected to return to their normal activities.

Hartigan BJ, Stern PJ, Kiefhaber TR. Thumb carpometacarpal osteoarthritis: arthrodesis compared with ligament reconstruction and tendon interposition. J Bone Joint Surg [Am]. 2001;83:1470-1478.

The authors retrospectively reviewed 109 patients (141 thumbs) younger than 60 years who were treated with either trapeziometacarpal arthrodesis or trapeziectomy with ligament reconstruction and tendon interposition. Fifty-nine patients (82 thumbs) were available to complete a questionnaire and examination with an average follow-up of 69 months. The arthrodesis group available for follow-up included 29 patients (44 thumbs), whereas the trapeziectomy with LRTI group included 30 patients (38 thumbs). Both groups were similar with regard to age, gender, hand dominance, and duration of follow-up. Additional patients in both groups were available to complete a questionnaire. Their results showed no significant difference with regard to pain, function, and satisfaction. The arthrodesis group had significantly stronger lateral pinch and chuck pinch, although grip strength did not differ. The LRTI group had significantly better range of motion with opposition and the ability to flatten the hand. There was a higher complication rate in the arthrodesis group, with nonunion the most common complication. Despite this, pain improved in all nonunions, and all were satisfied with the outcome. The authors concluded that both procedures had similar results with regard to pain, function, and satisfaction despite minimal differences in strength and motion. (Level III evidence)

Kenniston JA, Bozentka DJ. Treatment of advanced carpometacarpal joint disease: arthrodesis. Hand Clin.. 2008;24:285-294.

The authors present a review of carpometacarpal arthritis and its various treatment options, with special attention to arthrodesis. They include a detailed operative technique, discuss associated complications, and review the results reported in the literature over the past 40 years. They conclude that multiple surgical options are available for those patients who fail nonoperative management. These techniques are largely based on clinical symptoms, radiographic staging, and surgeon and patient preference. Arthrodesis remains an excellent option for patients with isolated CMC arthritis who require a pain-free and strong thumb. (Level III evidence)

Taylor EJ, Deari K, D’Arcy JC, Bonnici AV. A comparison of fusion, trapeziectomy and Silastic replacement for the treatment of osteoarthritis of the trapeziometacarpal joint. J Hand Surg [Br]. 2005;30:45-49.

The authors retrospectively reviewed the outcomes of three surgical treatments for osteoarthritis of the trapeziometacarpal joint. A total of 83 operations were performed (36 fusions, 25 trapeziectomies with [22] or without [3] ligament reconstruction, and 22 silicone trapezial replacements) with average follow-up between 33 and 42 months. The authors evaluated patient satisfaction, pain reduction, range of motion, tip and key pinch, and complication rates. They reported no significant difference in clinical outcomes among the three groups but noted a higher complication and reoperation rate in the fusion group. (Level III evidence)

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