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The objective of this study was to investigate the wear resistance of ultrahigh-molecular weight polyethylene (UHMWPE) and crosslinked polyethylene (XLPE) against different counterfaces. Friction and wear studies were evaluated under dry reciprocating sliding conditions at room temperature. TI6AI4V discs finished in polished, lapped, and ground conditions were reciprocated against polymer cylinders. In addition, abrasive wear studies were conducted using different abrasive grit sizes. The friction and wear properties of the two polyethylenes were strongly affected by the different counterfaces. XLPE showed important friction and wear sensitivity with the change of surface roughness of the TI6AI4V disc, as well as with the change in abrasive grit size. Scanning electron microscopy and energy-dispersive X-ray (EDX) analysis of the worn disc surfaces and the polymer pins indicated the wear mechanisms affecting the polyethylenes., INTRODUCTION Ultrahigh-molecular weight polyethylene (UHMWPE) and crosslinked polyethylene (XLPE) are extensively used biopolymers as a bearing material in total joint replacements (TJRs) [1], UHMWPE was used as a gold-standard material [...]

Adverse reaction to metal debris released from the taper‐trunnion junction of modular metal‐on‐polyethylene (MoP) total hip replacements (THRs) is an issue of contemporary concern. Therefore, a hip simulator was used to investigate material loss, if any, at both the articulating and taper‐trunnion surfaces of five 32‐mm metal‐on‐cross‐linked‐polyethylene THRs for 5 million cycles (Mc) with a sixth joint serving as a dynamically loaded soak control. Commercially available cobalt–chromium–molybdenum femoral heads articulating against cross‐linked polyethylene (XLPE) acetabular liners were mounted on 12/14 titanium (Ti6Al4V) trunnions. Weight loss (mg) was measured gravimetrically and converted into volume loss (mm3) for heads, liners, and trunnions at regular intervals. Additionally, posttest volumetric wear measurements of the femoral tapers were obtained using a coordinate measuring machine (CMM). The surface roughness (Sa) of femoral tapers was measured posttest. After 5 Mc, the mean volumetric wear rate for XLPE liners was 2.74 ± 0.74 mm3/Mc. The CMM measurements confirmed material loss from the femoral taper with the mean volumetric wear rate of 0.045 ± 0.024 mm3/Mc. The Sa on the worn area of the femoral taper showed a significant increase (p < 0.001) compared with the unworn area. No other long‐term hip simulator tests have investigated wear from the taper‐trunnion junction of contemporary MoP THRs. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:156–166, 2020. [ABSTRACT FROM AUTHOR]

Ceramic‐on‐ceramic (CoC) total hip replacements (THR) have a substantially lower wear rate than metal‐on‐polyethylene (MoP) hips, as shown by hip simulator testing. However, the revision rates of CoC and MoP hips are comparable. To try and explain this discrepancy the wear, at both the bearing surfaces and taper‐trunnion interface of 36 mm BIOLOXdelta CoC THRs, mounted on 12/14 titanium (Ti6Al4V) trunnions was investigated using a hip simulator (n = 3) and a dynamically loaded CoC sample in a separate test station. Wear was assessed gravimetrically and surface roughness measurements of the articulating and taper surfaces taken at regular intervals. Scanning electron microscopy, surface roughness, and gravimetric measurements of trunnions was performed. After 5 million cycles, the mean total wear from the ceramic articulating surfaces was 0.25 mm3 from the hip simulator test, and that from the titanium trunnions was 0.29 mm3. This metal wear may provide an explanation for adverse reaction to metal debris found in contemporary CoC hip joints. It is therefore vital to consider taper‐trunnion wear in preclinical testing of artificial hip joints. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1199–1209, 2019. [ABSTRACT FROM AUTHOR]