Mechanical Properties of Retrieved Highly Cross-linked Polyethylene Acetabular Liners in Total Hip Arthroplasty
Abstract
Highly cross-linked polyethylene (HXLPE) has replaced the conventional ultra-high-molecular-weight-polyethylene (UHMWPE) as the gold standard bearing surface in total hip arthroplasty (THA) due to superior wear characteristics and survivorship. However, HXLPE has demonstrated poorer mechanical properties, in vivo oxidation, and concerns of rim fractures. The purpose of this project was to study the mechanical properties at the rim of retrieved HXLPE acetabular liners.
We developed a simple technique for measurement of hardness at the rim of irradiated, remelted, HXLPE liners of a specific design. The effect of shelf time on mechanical properties of retrieved liners was determined and showed no correlation between hardness with shelf time. Furthermore, hardness testing of retrieved samples showed no correlation between hardness and time in vivo. This suggests that rim fractures in this design of liners are likely not a result of in vivo decline of mechanical properties.