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Abstract: The purposes of this study were to determine the spectrum of femoral head damage in patients undergoing revision total hip arthroplasty and to determine the impact of that damage on polyethylene wear. One hundred eight consecutive modular metal femoral heads were retrieved at revision surgery. The mean roughness (Ra) value was 0.18 ± 0.18 μm. The roughest femoral heads (mean Ra, 0.56 μm) were from retrievals correlated with mode 2 wear (recurrent dislocation and complete wear through of the polyethylene liner). Five million cycles of wear tests were performed using retrieved femoral heads against both new conventional and highly cross-linked polyethylene. The mean wear rate of conventional polyethylene was 15.9 ± 4.3 mg and that of highly cross-linked polyethylene was 0.04 ± 0.14 mg per 1 million cycles (P < .001). Highly cross-linked polyethylene was more resistant to wear than conventional polyethylene, even when mated against roughened femoral heads. [Copyright &y& Elsevier]

Abstract: This article reports on a commercially available extensively cross-linked ultrahigh molecular-weight polyethylene (HXPE) produced by subjecting molded GUR 1050 ultrahigh molecular-weight polyethylene (UHMWPE) to 100 ± 10 kGy of electron beam radiation followed by melt annealing and sterilization by gas plasma. When compared to contemporary conventional molded GUR 1050 UHMWPE sterilized by 37 kGy of gamma radiation, the HXPE material has enhanced wear properties, has no detectable free radicals, and is resistant to oxidation and oxidative-related material property changes. The relative wear improvement of the HXPE is maintained in the presence of bone cement or alumina particles. The HXPE produced greater than 90% fewer wear particles in all size ranges and statistically significantly (P < .0001) smaller average-size particles than did the conventional UHMWPE. [Copyright &y& Elsevier]

Abstract: A postclinical retrieval analysis was performed on 43 polyethylene tibial components of a contemporary total knee arthroplasty system with implantation duration between 12 and 80 months. Components were scored for 8 potential modes of surface wear or damage on the top and back surfaces. Moderate backside wear of 4.1 μm/y was documented by measuring the extent of manufacturer''s engraved lettering removal. Neither the topside nor backside score correlated with duration of in vivo function. No component experienced topside or backside delamination, cracking, or significant deformation. The greatest contribution to wear and damage score was pitting and scratching secondary to bone cement debris. The extent of both wear and damage experienced by these components was moderate, in comparison with that previously reported with older implant systems. [Copyright &y& Elsevier]