Convex condylar arthroplasty of the basal joint of the thumb: failure under load

Twenty-five convex condylar silicone arthroplasties were done for treatment of arthritis confined to the basal joint of the thumb. The procedure was done in 19 patients with osteoarthritis and in 6 patients with rheumatoid arthritis. The average follow up was 4 1/2 years. This series of condylar arthroplasties is compared with a series of 24 Swanson trapezial arthroplasties, all done for treatment of osteoarthritis, with an average follow up of 5 1/2 years. The convex condylar arthroplasty is associated with a 15% failure rate in patients with osteoarthritis coupled with radiographic findings of significant bone resorption around the stem of the prosthesis in 84% of the remaining patients. The three failures were in the osteoarthritic thumbs and not in the rheumatoid thumbs. Fusion and tendon interposition arthroplasty are described as options for revision. We believe that the Swanson convex condylar hemitrapezium replacement should be reserved for the low-demand rheumatoid thumb.