The role of the macrophage in periprosthetic bone loss.

Aseptic loosening after total joint replacement remains the most common reason for long-term implant failure. Macrophages activated by submicron wear particles of the polyethylene liner used in joint replacement have been shown to be the source of periprosthetic bone loss. Understanding the role of material chemistry in macrophage activation and the subsequent effects that macrophage-derived enzymes play in the degradation of implanted biomaterials is key to developing methods for prolonging the lifespan of implantable materials.