Correlation of the physicochemical, dimensional and packing characteristics with the wear behavior of metal-on-UHMWPE tribological pairs

This manuscript presents preliminary results on the combined effects of physicochemical, dimensional, and packaging characteristics of ultra-high molecular weight polyethylene (UHMWPE) acetabular inserts on the wear rates of metal-on-polyethylene tribological pairs. Wear tests were conducted on tribological pairs from three different manufacturers (A, B, and C), in triplicate for each manufacturer until each pair reached 5 million cycles. Surface finish, dimensional properties, and physicochemical characteristics of the inserts were evaluated and subsequently correlated and discussed based on the measured wear rates. Higher average wear rates were observed for all three tribological pairs from manufacturer B (71.71 +/- 10.61 mg per million cycles), which exhibited the largest diametrical clearance between components, higher surface roughness, and a higher oxidation index (0.329 +/- 0.027) compared to the other manufacturers. Additionally, samples from manufacturer B with poorer physicochemical properties were stored in packaging lacking an oxygen barrier. Therefore, the study demonstrated that even with a certain level of cross-linking, inadequate sterilization process control and the use of non-oxygen-barrier packaging can lead to higher subsequent wear compared to non-cross-linked material.