Abstract
The authors report their preliminary experience with a minimum of one year follow –up of hydroxyapatite coating as the means of fixation of the femoral head in hip resurfacing.
Between Dec 2003 and Dec 2004, of the 23 cases performed by the senior author,22 were available for follow up,15 were women (68.2%) and 7 were men (31.8). The femoral and acetabular components of the uncemented version of the CORMET 2000(Corin,Cire ncester,UK) were used. The surgical approach was the Hardinge approach in all cases. Patients were assessed pre-operatively for pain and function,using the Harris Hip Score. Post operatively they were assessed in clinic with x rays at 6 weeks,6 months and annually thereafter. X rays were evaluated for pre and post op neck shaft angle,giving an indication of varus or valgus placement of the head prosthesis. The lateral view was assessed to reveal anterior or posterior tilting of the prosthesis. Neck thinning was evaluated by measuring the ratio of the metal cup and bony neck diameters at the cup neck junction, recorded post op and at one year.
None of the femoral implants were placed in varus. Only one case had inferior notching, which had remodelled at one year. In the lateral view none of the cups showed a displacement of more than ten degrees in the AP direction. There were no stem lucencies or signs of femoral implant migration in any of the cases. None of our cases showed neck thinning (change in ratio greater than 10%). Uncemented femoral implant in a metal on metal resurfacing hip replacement appears to perform well and shows no catastrophic problems at the short term one year follow up. Longer follow up studies are necessary
Correspondence should be addressed to Mr Bimal Singh, BOSA at the Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE
