In Vivo Wear Performance of Highly-crosslinked Polyethylene in Total Hip Arthroplasty

Highly cross-linked polyethylene (HXLPE) has been a major advancement in total hip arthroplasty (THA), significantly reducing wear rates and the need for revisions compared to conventional ultra-high molecular weight polyethylene. However, volumetric wear and the associated periprosthetic tissue response remain one of the key issues in long-term THA outcomes; in fact, recent findings indicate that HXLPE components generate finer wear particles that seem to induce a stronger inflammatory cell response, potentially leading to osteolysis and subsequently implant failure. Also, variations in the manufacturing processes of HXLPE across different manufacturers may influence the cross-linking degree of the polymer, thus significantly affecting the in vivo tribological behavior of these materials. Thus, this study is designed to address three specific goals: 1) To establish volumetric wear rates of surgically retrieved HXLPE liners, and to identify material, patient demographic, and surgical positioning factors that drive wear and its in vivo patterns. 2) To determine the robustness of wear assessment of retrieved HXLPE liners with an optical CMM, and 3) to determine the contribution of intracellular PE wear accumulation on the periprosthetic tissue response associated with PE liners. From a cohort of 120 retrieved HXLPE liners, 80 were analyzed, revealing that Highcross liners appear to have a wear rate more than times higher than Durasul liners (median of 15.7 mm3/y vs 3.7 mm3/y). Significant determinants of wear rate included time in situ, American Society of Anesthesiologists Physical Status Classification System and weight. A machine learning-based approach for wear pattern analysis was established and revealed five distinct clusters, characterized by significantly different wear scar location, volumetric wear, wear rates, and liner sphericity. Wear assessments via optical CMM were shown to have excellent inter-rater reliability, as well as repeatability, while also proving consistent results compared to physiologically accurate simulator testing. Optical CMM results showed an absolute median deviation of 22.9 mm3 (14.9%) from the gravimetric measurements, when sufficient reference area was available. FTIR-I confirms phagocytic uptake of wear particles and the early inflammatory response characteristic of osteolysis, even when undetected via conventional histological analysis. While still at a preliminary stage, detection of intracellular accumulation of HXLPE particles and Macrophage Scores positively correlated with wear rates (C = 0.692, p = 0.001; C = 569, p = 0.014).

Author dc:creator

• Valerio Porrati (24399506)

• Total Hip Arthroplasty

Statement dc:rights

• In Copyright

DOI dc:identifier

https://doi.org/10.25417/uic.32993945.v1

OAI identifier oai:identifier

oai:figshare.com:article/32993945