Development of a Rate-Dependent Material Model for UHMWPE Joint Replacement Components

Polyethylene wear has been implicated in osteolysis and can lead eventually to implant loosening. Abrasive/adhesive wear and delamination or pitting damage in ultra-high molecular weight polyethylene (UHMWPE) joint replacement components has been in part attributed to high joint contact stresses. The propensity of total joint replacement systems for these types of wear is often assessed by evaluating the joint contact stresses and contact areas and these often serve as a basis for differentiation of systems. The rate-dependency of polyethylene can have a significant effect on these contact characteristics of joint replacement components. Previously, researchers have used experimental and analytical methods to determine joint contact characteristics. Most of the analytical studies, however, have not included the important time-dependent behavior of UHWMPE.