Comparison of Wear in Fixed and Mobile Bearing Knee Designs

Ultra High Molecular Weight Polyethylene (UHMWPE) remains the only bearing surface of choice in total knee replacements (TKR). While excellent medium term results can be found for knee replacements at ten years, there remains concerns about wear debris induced osteolysis in the longer term, particularly in young and more active patients. It has been shown previously that the wear of fixed bearing knees increases markedly with elevated kinematic inputs, as might be expected in more active, high demand patients. While in the knee there is interest in modified polyethylenes to reduce wear and osteolytic potential, little is known about the impact of different design variables. Rotating platform (RP) mobile bearing knee design options are now becoming available in a number of fixed bearing knee designs. The aim of this study was to investigate the wear of a rotating platform mobile bearing component with that of a fixed bearing component of the same design.