Highly Crosslinked Vs Conventional Polyethylene Particles: Relative In Vivo Inflammatory Response

Crosslinked polyethylenes have been introduced to reduce wear and osteolysis. The osteolysis rate depends on many factors including the biologic activity of the wear particles. This study examines the relative inflammatory potential of highly crosslinked and non–crosslinked polyethylene particles. Polyethylene particles were crosslinked and characterized. Dose-response curves were generated for endotoxin-positive and endotoxin-negative particles at each degree of cross-linking using an in vivo model. The 10-MRad crosslinked polyethylene was more inflammatory than an identical dose (25 mg/mL) of non–crosslinked polyethylene (P = .05). Endotoxin increased the inflammatory response to crosslinked and non–crosslinked polyethylene in a similar fashion. These data suggest that the improved wear characteristics of highly crosslinked polyethylenes may be offset somewhat by the modestly increased inflammatory profile of the highly crosslinked compared with non–crosslinked particles.