Tribology of Artificial Joints

More than half a million hip, knee, shoulder, elbow, wrist, finger, and ankle joint prostheses made from engineered materials are implanted world-wide every year to replace diseased natural joints. The breakthrough in artificial joint replacement was achieved with the introduction of approved materials, such as CoCrMo cast alloys with suitable biocompatibility and resistance and with optimized implantation technique using aseptic surgery. Nowadays joint replacement operations are standard, with long-term success rates of more than 10 years [3, 4]. Materials which can be used as biomaterials in endoprosthetics are subjected to complex conditions. For this reason, so-called modular prosthesis systems, which partly resolve the conflicting requirements for components with fixation and tribological requirements, have found wide use in recent years. Using the knowledge from more than 20 years ago, that it is primarily polymer wear particles which significantly affect the long-term results of cemented and cementless prostheses due to osteolysis and subsequent loosening, there is now increased interest in the tribology and material optimization of articulating components of implants [1, 23]. This contribution provides an overview of the tribological validation of new material combinations and designs, together with a brief report on experience.