A long-term follow-up of silicone-rubber interposition arthroplasty for osteoarthritis of the thumb carpometacarpal joint.

There are several surgical options for osteoarthritis (OA) of the thumb carpometacarpal (CMC) joint. This paper presents our long-term clinical and radiographic review of 12 thumbs in ten patients treated by partial trapezial excision and silicone-rubber interposition arthroplasty. The follow-up period averaged 15; three years with a ten-year minimum. Although the procedure provided early pain relief in most thumbs, all but two had mild to severe pain at follow-up. The average range of post-operative palmar abduction was 23 degrees. The average post-operative grip strength was 9.5 kg. Both tip and key pinch between thumb and index finger averaged about 50% that of normal subjects. Dislocation of the implant occurred in two joints and breakages in five. Bony erosions around the implant, which we attributed silicone synovitis, were found in four thumbs. The indications for silicone-rubber interposition arthroplasty for OA of the thumb CMC joint should be severely restricted as these produced unsatisfactory long-term results.