Abstract
Aims: The aim of this study was to evaluate a highly cross-linked polyethylene WIAM in cemented hip arthroplasty. This new polyethylene has been resistant to wear in laboratory tests. Methods: 60 patients (30 women, 30 men) with a median age of 55 years (35–70) and a median weight 82 kg (47–120) were included. All patients received a Spectron femoral stem with a 28 mm head in chrome-cobalt. The patients were randomised to acetabular cups made of either WIAM (electron beam irradiation 9.5 Mrad) or conventional polyethylene (CP) sterilized in inert atmosphere. Radiostereometric examinations (supine) were done 7 days after the operation and after 3, 6 12 and 24 months. Examinations (standing) were performed at 3, 6 12 and 24 months. The migration of the femoral head centre in relation to the polyethylene marker represented the femoral head penetration. Results:. 43 hip (19 WIAM 24 CP) were available for 24 months FU. There were no differences in cup migrations between the two groups. The mean proximal penetration (supine and standing) was less than 0.2 mm at 24 months in both groups p> 0,06 Conclusions: The femoral head penetration during the first two years may be dominated by creep. There is tendency for lower proximal penetration at standing examination in the WIAM group. Futher studies and longer follow up is necessary until highly crosslink polyethylene can be recommended for general use.
Theses abstracts were prepared by Professor Dr. Frantz Langlais. Correspondence should be addressed to him at EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
