**2. Materials for bearings of hip prostheses**

Materials are very important for the long-term success of THA. Since the introduction of low friction arthroplasty (LFA) by Sir John Charnley in the 1960's, much has been learned about the durability and biocompatibility of materials used in joint replacement. Concerns about higher rates of aseptic loosening and subsequent prosthesis revision among young and active patients have lead to the development of new implant designs and alternative bearings (Muratoglu & Kurtz, 2002). Strength and endurance, friction and wear properties, inertness and biocompatibility of the materials should be optimized in order to eliminate or diminish to a negligible extent the reaction of the organism to wear debris.
