METAL VERSUS POLYETHYLENE WEAR PARTICLES IN TOTAL HIP REPLACEMENTS

Research has recently been focused on the development of hip replaceme nts with alternative bearing surfaces with cobalt chrome alloy, to avo id the production of polyethylene wear particles in hip replacements a nd polyethylene wear debris mediated bone lysis, Cobalt chrome on coba lt chrome bearing surfaces are being reevaluated. Characterization of wear particles and studies on the reaction of the body to these partic les, have played an important role in the determination of the factors that cause aseptic loosening and will therefore play an important rol e in the comparison of metal on polyethylene and metal on metal hip pr ostheses, In this paper, a comparison between the different aspects of metal and polyethylene wear particles is made using data from the lit erature and the authors' experience. The authors conclude that techniq ues need to be optimized to isolate and characterize individual metal wear particles from periprosthetic tissues and they advocate the perfo rmance of in vitro studies with these in vivo generated wear particles or comparable particles.