[Functional study of Swanson's metacarpophalangeal arthroplasties in rheumatoid arthritis].

To validate a functional hand evaluation and to obtain an historical control group in a project of metacarpophalangeal total joint prosthesis, we reviewed our experience over a ten year period of Swanson's metacarpophalangeal joint arthroplasty in rheumatoid arthritis. Forty-nine implants in fourteen rheumatoid arthritis patients were reviewed clinically, radiologically and evaluated by the Arthritic Hand Function Test. The mean follow up was 4.5 years. All patients were ready to repeat the experience except one. The mean metacarpophalangeal joint range of motion was 37 degrees (18 degrees to 55 degrees) with a mean of 7 degrees ulnar deviation. Although their functional performance was 50% of normal, all patients completed the test. The strength was generally greater on the operated side. The low complication rate (6% fracture rate) with the successful functional outcome of Swanson's metacarpophalangeal joint arthroplasty in rheumatoid arthritis will be the gold standard for any new implant to develop.