MEDICAL GRADE HYDROXYAPATITE - STATE-OF-THE-ART

A review is presented of the state of the art of the use of medical gr ade hydroxyapatite (HA) both in bulk ceramic form and as applied as a coating to metallic substrates. Ceramic HA material is bioactive, on t he basis of which it has considerable potential benefits for use in th e medical field. Some applications have already proved to be successfu l in clinical trials, e.g. HA granules and preforms for bone grafting and augmentation. Unfortunately, the mechanical properties of HA in bu lk ceramic form have proved to be limiting factors for use in load bea ring applications. To overcome these limitations the use as a coating deposited by plasma spraying on suitable metallic substrates has been developed. Hydroxyapatite coatings have been used on dental implants a nd on orthopaedic endoprostheses, most importantly in hip and knee ope rations. There are very reliable clinical reports that HA coatings imp rove the osseointegration of hip and knee joints.