Arthroplasty of the knee in osteoarthritis and rheumatoid arthritis

147 cases of arthroplasty of the knee were reviewed. Three types of prostheses were used, viz., St. Georg, Geomedic and hinge (Shier and Guépar). Pain was the most common indication for the operation which produced complete or almost complete relief in 90% of the cases. In half of the joints with a mobility of less than 80 degrees preoperatively, the range of movement was increased to more than 80 degrees by the operation. Lack of extension, deformity and instability could be largely corrected. Two cases of deep infection were observed, both in patients treated with a hinge prosthesis. In one of them the complication led to amputation above the knee and in the other to arthrodesis.