35: Silicone Metacarpophalangeal Joint Arthroplasty

Procedure 35 Silicone Metacarpophalangeal Joint Arthroplasty



Nathan S. Taylor, Kevin C. Chung


imageSee Video 27: Silicone Metacarpophalangeal Joint Replacement Arthoplasty for Rheumatoid Arthritis



Indications




image Finger metacarpophalangeal (MCP) joint contracture or subluxation in rheumatoid arthritis (RA) patients


image MCP joint contracture or dislocation in patients with other rheumatic conditions, such as scleroderma or systemic lupus erythematosus



Examination/Imaging



Clinical Examination




image The patient’s MCP joints should be evaluated for range of motion and stability. If the MCP joints are not dislocated but the fingers are drifted ulnarly, intrinsic transfer may be performed to correct the finger misalignment for the small, ring, and long fingers; the radial sagittal band of the index finger is tightened to centralize its extensor tendon because no ulnar intrinsic tendon is available for transfer.


image With chronic subluxation of the MCP joints, ligamentous contracture around the joints cannot be corrected by soft tissue reconstruction alone. MCP joint arthroplasty is the preferred option in most of these cases.


image The thumb MCP joint laxity should be assessed, which is best treated with MCP joint fusion at the time of silicone MCP arthroplasty (SMPA).


image For patients who have collapse of the wrists and radial deviation of the metacarpals, the wrist problem should be addressed first either by fusion or by arthroplasty. Otherwise, the radial deviation of the metacarpals will cause early postoperative ulnar subluxation of the fingers after SMPA. Realigning the metacarpals by means of the wrist procedures will enhance the outcome of SMPA.



Imaging




image Posteroanterior, lateral, and oblique radiographs of the hand and wrist are essential to identify joint alignment, joint congruity, and bony erosions.



Surgical Anatomy




image The MCP joint is a condylar joint that allows flexion and extension but also radial and ulnar deviation.


image The radial and ulnar sagittal bands stabilize the extensor tendon, keeping it over the dorsal midline of the MCP joint. The sagittal bands are attached to the volar plate.


image The lateral bands pass volar to the MCP joint and dorsal to the proximal interphalangeal (PIP) joint. Contraction of the intrinsic muscles through the lateral bands causes MCP joint flexion and PIP joint extension (Fig. 35-1).


image The cause of tendon subluxation at the MCP joint in RA is joint synovitis altering the ligamentous support in the joint. The hypertrophic synovial tissue distends the ligamentous support of the joint, resulting in stretching of the radial and ulnar sagittal bands. Forceful gripping in daily activity tasks stresses the radial sagittal band, resulting in weakening of the radial support.


image Progressive ulnar subluxation of the extensor tendons causes the ulnar drift seen in RA hands.


image Chronic ulnar subluxation of the extensor mechanism results in ulnar lateral band contracture, which eventually causes fixed contracture of the ulnar lateral bands.


image

FIGURE 35-1



Positioning




image 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




image A transverse incision is made over the head of the metacarpals for wide exposure of all affected joints while preserving the dorsal veins and sensory nerves (Fig. 35-2A and B).

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28: Pronator Teres Rerouting 34: Reconstruction of the Central Slip with the Transverse Retinacular Ligament for Boutonnière Deformity 85: Wrist Denervation 38: Reconstruction for Congenital Thumb Hypoplasia 65: Arthroscopic Treatment for Septic Arthritis 89: Total Wrist Fusion

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Mar 5, 2016 | Posted by in Hand surgery | Comments Off on 35: Silicone Metacarpophalangeal Joint Arthroplasty

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