Wear Debris in Prothesis for Biomaterials

Abstract

The total replacement of damaged or diseased synovial joints represents one of the greatest advances in orthopaedic surgery of the 20th century. Whereas replacements are available for the shoulder, ankle, elbow, knee, hip accounts particularly for the most surgical interventions. Currently in the world several thousand hip joints per year are replaced and all the implants consist of a sliding pair represented by a hard counterface, either metal or ceramic, and a softer polymer. Since the early of 1960’s, Ultra High Molecular Weight Polyethylene (UHMWPE) became the dominant polymer for bearing surfaces in orthopaedic surgery. However, generation of UHMPWE wear debris from bearing surfaces in patients still the major problem for the long term implants. Both volume and morphology of the wear particles are important to determine the response of the body to debris and subsequent effects on secure fixing. This paper presents a review of the type of particles which are the most frequently, found in biopsies of tissues from explanted prostheses. Indeed, the size and the amount of these debris are very important factors for a better understanding of wear processes in artificial joints. Real wear particles are also described in this paper.