New knee prosthesis with bisurface femoral component made of alumina-ceramic; its concept and clinical performance

摘要

The alumina ceramic is well known to have good biocompatibility and high wear resistance. In a total hip replacement alumina-ceramic head is used combined with polyethylene socket. However, as to a total knee replacement alumina-ceramic component has scarcely used. We have developed new total knee prosthesis with alumina ceramic femoral component designated Bisurface knee prosthesis. Bisurface knee has been designed mainly according to the total condylar prosthesis by the cooperation of Kyoto University and Kyocera Co. Bisurface knee has a unique ball-and-socket joint in the center of the posterior portion of the ftibiofemoral articulation to improve range of motion. In our institute, 233 joints were replaced with Bisurface knee fixed with bone cement since 1990 until 1994. We followed 176 joints (135 cases) from 4 to 8 years (average 5.2 years). The average of knee score improved from 47 preoperatively to 81 at follow-up time. The average of flexion angle changed from 119 to 124 degree. Five cases were operated according to infection. Three cases were revised due to instability or a breakage of the patellar peg. At six-year follow-up, the survival rate was 97perent. These results showed Bisurface knee with alumina ceramic femoral component has an excellent clinical performance.