Alumina

Although the origin of the development of alumina as a biomaterial can be traced back to 1930, its successful use as a biomaterial is based on the studies carried out in the early 1970s in France, Germany, and Japan. Alumina has 40 years of clinical record in the field of orthopedics, where it is used in the manufacture of balls and cups for hip replacements and has proven its effectiveness in limiting the bearing wear. The arthroplasty of the hip is one of the most successful surgeries, with very positive outcomes but its success is hampered in a number of cases by the insurgence of osteolysis, a device-induced pathology, which also arises out of the reactions induced by the wear debris. This explains the interest shown in minimizing the wear of bearings in arthroplasty and the continuous efforts taken to improve the materials selected for this task. This chapter outlines, from an historical perspective, the development of alumina as a biomaterial, reviews the properties of this ceramic that are relevant for its clinical use, with emphasis on the studies performed on the biological safety of alumina and of its wear debris. Special attention is devoted to the use of alumina in total hip replacement (THR) bearings, which is the main application of alumina as a biomaterial today, while a section is devoted to the use of this ceramic biomaterial in the knee and to the ongoing development of alumina matrix composites.