Wear Performance of Ultra-High Molecular Weight Polyethylene on Oxidized Zirconium Total Knee Femoral Components

Wear debris can lead to osteolysis and aseptic loosening after total knee arthroplasty1,2. Efforts to reduce wear of total knee replacements have focused primarily on improving implant design and the quality of ultra-high molecular weight polyethylene. Although these efforts have addressed issues related to fatigue wear of the ultra-high molecular weight polyethylene component, concerns remain about adhesive and abrasive wear caused by the hard counterface of the femoral component. Previous studies have shown that roughening of the condyles occurs clinically and that many observed scratches have a shape and orientation that can increase polyethylene wear (Figs. 1, 2, and 3)3-8. Not only does volumetric wear of polyethylene increase with increasing counterface roughness, it also has been found that increasingly sharp peaks associated with counterface scratches increase the tendency for the production of submicrometer-sized debris that may be related to osteolysis9. These findings suggest that a hard counterface that resists roughening and provides low friction with ultra-high molecular weight polyethylene should reduce abrasive and adhesive wear and thereby prolong the survival of total knee replacements.