The authors report twenty-one cases in which the Swanson prosthesis was used in the treatment of Kienböck's disease. Eighteen of the patients were followed up after between six months and seven years. The results were good in 94.5 per cent of cases. The operation resulted in all cases in the disappearance or reduction of pain. In many instances it also improved the mobility of the wrist and the strength of the muscles. The prosthesis was found to be well tolerated with time. The results were also good in the advanced stages of the disease.