Knee Simulator Wear of Cross-linked Uhmwpe with Normal and Mal-rotation Kinematics

Introduction: Wear of ultra-high molecular weight polyethylene (UHMWPE) is a major factor that affects longevity of the total joint replacement. In total hips (THR), cross-linking of polyethylene has been shown to be highly effective in reducing wear both clinically and experimentally [1-3]. Also, in TKR, Schmidig et al. [4] showed a 90% reduction of wear rate in 10 Mrad compared to 3 Mrad tibial inserts. Thus cross-linking appears to also provide substantial improvement in the wear resistance of tibial inserts. However, there may be concerns that as cross-linking is increased to minimize wear problems, any deterioration in mechanical properties may result in physical degradation. Our objective was to compare 3 Mrad UHMWPE with 10 Mrad highly cross-linked polyethylene (HCLPE) in the same TKA design using both a standard kinematics and a more severe mal-rotation kinematics. Our hypothesis was that HCLPE would be more wear resistant than the standard UHMWPE even in the mal-rotation model.