Abstract
The implantation of Total Hip Replacements (THR) has become the standard treatment for advanced osteoarthritis of this joint. Since the first articular replacements using monopolar components, hardware has been improving from cemented to porous coated noncemented implants and more recently hydroxyapatite coated (HAC) prosthesis. We started using HAC replacements in 1989 and we have been increasingly using these implants since then, even expanding its indications.
From 1989 to 1999 we have implanted 140 THR using a HAC model. The clinical records and X-rays of these patients were reviewed 5 to 15 years after the implantation of the primary prosthesis.
Results: The average age at surgery was 61.71 years, ranging from 18.7 to 83.5. At an average follow up of 9.17 years, 21 of them required a revision. In two cases both the stem and cup were replaced and in 19 only the acetabular cup was replaced.
This yields a survival rate of 85% and a revision rate of 15% for cups after an average of 9.17 years and a survival rate of 98.57% and revision rate of 1.43 for femoral stems. The revision was done at an average of 1.37 years when femoral components were involved (in 2 cases) and 6.79 for isolated acetabular components (in 19 cases). The overall survival of the revised prosthesis would have been 6.28 years. The main cause for revision was related to acetabular loosening and polyethylene wear in 18 cases, 2 for component malposition and one for infection.
Discussion and conclusions: Our results show that HAC THR offer a good long and mid term survival rate. However, the design of the acetabular component and polyethylene need further investigation to improve fixation to bone and wear resistance, respectively.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
