Eighteen patients who had rheumatoid wrist surgery with resection of the distal ulna, with or without implant arthroplasty, were reviewed at an average follow-up of 32 months. Subjective and objective clinical findings did not confirm any advantage to the routine use of implant arthroplasty of the distal ulna. Moreover, a bone resorptive process, which was identified in all implant cases, may cause clinical symptoms and prosthetic instability and may warrant reoperation. The histologic findings supported a granulomatous reaction to a foreign body as a cause of the resorptive process. Histologic examination showed a synovial type of membrane and the feasibility was raised of an enzymatic cause.