Abstract
Cemented Total Hip Arthroplasty gives good results for 10 or more years, but is too often complicated by a combination of mechanical loosening, wear debris and osteolysis.
Patients require an implant which will last the rest of their life. Cemented hips may not survive and a better alternative is needed.
Furlong hydroxyapatite ceramic coated (HAC) implants have been used for more than 19 years and to date there are 2248 primary hip arthroplasties.
Fixation of the implants with HA ceramic is entirely satisfactory; histological studies from post-mortem specimens have confirmed that there is good cancellous bone fixation to the HA. The hydroxyapatite behaves like bone and is replaced by creeping substitution. This results in a Perfect Fit with no intervening fibrous tissue. Fixation is therefore maintained.
Aseptic loosening is rare; eleven components. Polythene wear is a problem. Those patients with ceramic/polythene couples who have now reached about 15 years since surgery are showing wear of the liner evidenced by eccentricity of the ceramic head in the liner. Three of these have completely destroyed the liner and the titanium shell.
Ceramic/ceramic bearings do not seem to wear, although there have been occasional fractures of alumina. For the last two years Biolox Delta, a stronger compound ceramic material, has been available from Ceramtec. There are no reports of any fractures.
Patients who have a life expectancy of more than 10 or 15 years should be fitted with an HA coated implant with ceramic bearing surfaces. This may provide the answer for the long-lasting hip prosthesis.
