Polyethylene Particles from a Hip Simulator Cause 45Ca Release from Cultured Bone

Abstract

Periprosthetic osteolysis is a dominant factor in the success or failure of total hip prostheses. Polyethylene wear debris has been implicated in the process of bone resorption and subsequent implant loosening. The present study is the first to examine the effect of ultra high molecular weight polyethylene (UHMWPE) wear debris produced by a hip simulator on calvarial bone resorption in vitro. 45Ca release was measured in cultured mouse calvarial bone samples. Although short-term exposure to UHMWPE particles (2 h) decreased 45Ca release, longer-term exposure for 1–2 days increased release in a dose-dependent manner. After one-day exposure to 7.5 × 106 particles per mL, 18% more 45Ca was released from cultured calvarial bone than from control samples. It was concluded that UHMWPE wear particles either directly or indirectly stimulated osteoclasts to activate bone resorption. Polyethylene wear debris contributes to the osteolytic process at the bone-implant interface.