Bioceramics in orthopaedic surgery: state of the art and preliminary results

Ceramic materials utilized in orthopaedic surgery can be divided into bioinert, causing minimum tissue reaction, and bioactive types, capable of stimulating bone tissue growth, establishing a bond capable of supporting physiological loads. Alumina is a bioinert ceramic which shows excellent mechanical resistance and an extremely low level of wear when given appropriate structural characteristics. It is therefore used to make prosthetic hip components (head and acetabulum), to coat metal prosthetic shafts and to make prostheses for small joints. Among the bioactive ceramics, bioglass, bioglaze and hydroxylapatite are included in the study. At present, bioglass and bioglaze appear interesting, but not sufficiently so as to find a precise niche in orthopaedic surgery. Currently the bioactive ceramic with the most possibilities for use in orthopaedic surgery is hydroxylapatite. The close interfacial bond which is established with bone tissue allows it to be used as a filler for defective bones in various skeletal diseases and as a coating for metal prosthetic substrates.