Thirty-nine patients with Kienböck's disease underwent silicone replacement arthroplasty between 1979 and 1994. The patients were followed-up from 1 to 18 years (mean, 8 years). Sixteen prostheses (41%) have had to be removed, from 1 to 18 years postoperatively (mean, 5.6 years), 15 of them because of pain and silicone synovitis or cysts. It appears that silicone synovitis with cyst formation is an inevitable problem in the wrist after silicone replacement arthroplasty of the lunate, and this procedure is only a temporary solution for Kienböck's disease.