The biology of alternative bearing surfaces in total joint arthroplasty

Periprosthetic osteolysis is currently the dominant limiting factor in joint arthroplasty longevity. Because this process is predominantly a biologic response to particulate wear debris and/or corrosion products, alternative bearing surfaces and highly cross-linked polyethylenes have been developed in an attempt to reduce the incidence of wear-induced periprosthetic osteolysis. These alternative bearing surfaces currently include ceramic-on-polyethylene, ceramic-on-ceramic, metal-on-metal, and metal or ceramic on highly cross-linked polyethylene. Although these alternative bearings diminish the generation of polyethylene debris, metallic or ceramic debris is produced. In addition, the biologic response to debris generated from alternate bearings is not fully elucidated and is related not only to particle number, but also to particle size, shape, composition, and surface area.