Since 1970, 170 knees have been operated upon using the Kodama-Yamamoto knee prosthesis. Of these 127 had the revised Mark-II prosthesis and of this group 91 cases have been followed for more than a year. Interim results suggest that the total knee score has improved. on the average, from 38 points preoperatively to 74 points after one year. A single early complication involved loosening of the prosthesis in a case of knee infection. Except for this case, no loosening and no radiolucent lines have been observed. Methacrylate bone cement is known to be harmful to bone and soft tissues, and our basic and clinical studies reveal that results improve when the total knee replacement is done without using cement.