Rheumatoid Arthritis: Metacarpophlangeal Joint Reconstruction Arthroplasty

73 Rheumatoid Arthritis: Metacarpophalangeal Joint Reconstruction Arthroplasty

R. John Naranja, Jr. and Kevin D. Plancher

History and Clinical Presentation

A 53-year-old right hand dominant woman was originally diagnosed with rheumatoid arthritis 14 years ago. Medical management of her disease process has included chronic oral prednisone. Her primary complaint includes pain and deformity of her hands and decreased function secondary to lack of mobility and strength.

Physical Examination

The patient has ∼25 degrees of ulnar drift at the index through small finger metacarpophalangeal (MP) joints. An extension deficit at the MP measures ∼50 degrees (Fig. 73–1). The arc of motion of the digits at the MP joint is 20 degrees. Key pinch strength is 30 N and grip strength is 70 N at position II using the Jamar dynamometer. There is relative preservation of joint motion at the proximal interphalangeal (PIP) joint and wrist articulations without significant collapse or deformity.

PEARLS

Meticulous detail is necessary when reaming the proximal phalanx of the little finger when there is poor bone stock and especially in patients with juvenile rheumatoid arthritis.
When silicone synovitis and loss of bone stock occur, a resection arthroplasty should be considered.

PITFALLS

Inadequate soft tissue balancing and poor hand therapy can lead to recurrence of the deformities and subluxation of these joints.
Use of silicone implants can lead to an inflammatory response with subsequent erosive changes.

Diagnostic Studies

Radiographs of the hand to include posteroanterior (PA) (Fig. 73–2), lateral, and oblique views demonstrate subluxation and joint destruction of the MP joints in the index through small fingers of the right hand. Though there is relative diffuse osteopenia present, adequate bone stock appears present for potential implant arthroplasty.

Figure 73–1 A classic ulnar drift and extension deficit in a rheumatoid hand seen at the metacarpophalangeal joints. (Illustration courtesy of The Indiana Hand Center and Gary Schnitz.)

Figure 73–2 Posteroanterior (PA) radiograph of metacarpophalangeal (MP) subluxation and joint destruction.

Differential Diagnosis

Degenerative joint disease

Rheumatoid arthritis

Septic joints

Diagnosis

Rheumatoid Destruction and Deformity of the Index through Small Finger Metacarpalphalangeal Joints

The MP joint in the rheumatoid hand is commonly affected by joint destruction and deformity. Typically, the disease process involves bony articular destruction, and ulnar and volar capsular contracture with concordant radial capsular attenuation. This subsequently results in subluxation of the flexor sheath in an ulnar and volar direction in addition to ulnar displacement of the common extensor tendon. Intrinsic tightness contributes to overall dysfunction. Indications for arthroplasty reflect the disease process and include pain and disability with radiographic evidence of joint destruction, limited MP range of motion secondary to contracted myotendinous and ligamentous supports, ulnar drift that has failed other soft tissue procedures, and stiff distal interphalangeal (DIP) or PIP joints. Arthroplasty of the MP joint predictably addresses these processes and maintains function better than arthrodesis or simple resectional arthroplasty in patients with adequate bone stock, soft tissue coverage, and absence of preexisting infection.

Metacarpophalangeal destruction and deformity are often accompanied by PIP joint deformity and wrist collapse. Timing of surgical interventions as well as consideration of other joint involvement (e.g., hip and knee involvement/shoulder and elbow involvement) requiring further load bearing on the diseased upper extremity following surgery must be noted. With associated wrist involvement, reconstruction of the wrist followed by the MP joint is appropriate. The exception is in the face of an extensor tendon rupture with decreased passive MP range of motion. Metacarpophalangeal arthroplasty should be performed first to gain passive motion in association with the extensor tendon repairs at the level of the wrist.