Characterization of UHMWPE Wear Particles

Although most total joint prostheses remain stable for many years, a significant proportion experience loosening, with about 10% requiring revision 10 years after primary arthroplasty. It is generally accepted that osteolysis, among other causes, is initiated by the biological response to wear particles, which are released from ultra high molecular weight polyethylene acetabular liners and tibial trays. Wear particles up to 10 μm in size are predicted to be phagocytosed by resident macrophages and cause the release of inflammatory cytokines and chemokines, including tumor necrosis factor alpha (TNF-α), interleukin-1beta (IL-1β, IL-6, and IL-8. These cytokines stimulate the release of other mediators and the ensuing inflammatory cascade results in the formation of a periprosthetic granulomatous tissue reaction. Histopathological studies have revealed that these inflammatory cytokines facilitate osteoclastagenesis, which results in resorption of bone and a painfully loose implant. Revision surgery is currently the only option for the patient and surgeon.