Biomaterials for Total Joint Replacements

Abstract

The use of orthopaedic implants is growing rapidly in both number and sophistication. Metals and alloys, ceramics, carbons, polymers, combinations and composites are all used as biomaterials for total joint replacement ( TJR) devices. Limitations associated with long-term function in younger and more active patients have resulted in concerns about existing longevities. In this regard, properties and functional interactions have been reviewed to assess some of the relative magnitudes and possible limitations. Wear, which has been implicated as the major cause of osteolysis, is emerging as the principal limit on successful long-term fixation of total joint components, whereas aseptic loosening has resulted in loss of tissue support, motion, pain, and device revisions . Up to now, there exists no material in the world of which its properties are considered best for the production of orthopaedic implants. As a matter of fact, each material, with its specific property determined by its composition and processing technique, carries with it an inherent set of advantages as well as disavantages in implant design. Current theories suggest that three- dimensional composites with anisotropic property similar to the tissues being replaced are still under investigation, whereas biochemical bonding to tissues could help to optimize conditions of force transfer, tissue maintenance, and function. Surface modifications and combinations of highly wear-resistant biomaterials for articulation could also result in minimal magnitudes of wear-based debris. Through the continuation of clinical observation and selection of devices most suitable for the individual needs of each patient, progress in biomaterials and technological developments will continue to contribute to orthopaedic surgery.