The rheumatoid hand. Reflections on metacarpophalangeal arthroplasty.

Metacarpophalangeal (MP) implant arthroplasties have been widely used during the past 15 years. It is difficult to evaluate the effectiveness of MP arthroplasty. Patients with rheumatoid arthritis are so varied that meaningful comparisons of results from different series are not possible. However, certain factors influence the results of this operation. Some of these factors are related to the patient's motivation. Others include the condition of the adjacent joints and tendons. Staging of multiple procedures is advisable. The surgical technique is exacting. Postoperative therapy is vital in achieving maximum benefit from MP arthroplasties. Complications of this procedure include infection, prosthetic fracture, recurrent deformity, and limited motion. The concept of the flexible hinged prosthesis acting as a spacer to encourage encapsulation is good and is generally successful in improving hand function while correcting deformity and relieving pain.