Histologic comparison of tibial articular surfaces against rigid materials and artificial articular cartilage.

After endoprosthetic replacement of the femoral head, marked pathologic changes of the acetabulum, such as penetration and ulceration, often occur. These changes are caused by the rigid material surface properties of the prosthesis and the lack of damping effects. In this study, we compared the time-dependent changes of tibial articular surfaces with three kinds of femoral implant under loading conditions in dogs. Marked pathologic changes of the menisci and tibial articular cartilage were observed from 8 weeks after implantation with hard material implants, whereas the tibial joint surface against an artificial articular cartilage was still intact 24 weeks postoperatively. These results showed clearly that marked pathologic changes of the articular cartilage against rigid materials occurred and were caused by the surface properties of the counterfaces and high friction coefficients of ceramic and metal materials used.