A radiological and laboratory assessment of polyethylene wear in failed total hip replacement

This study assessed the reliability of radiological assessment of polyethylene wear in loose total hip replacements (THRs) by comparing it with a laboratory assessment using the shadowgraph technique. It was performed in Avon Orthopaedic Centre, Southmead Hospital, from September 1997 to June 1998. True linear wear depth measured using the shadowgraph technique was 42% greater than that determined from the radiological femoral head eccentricity in standard non-weightbearing plain x-rays. There was an inverse statistically significant correlation between cup inclination angle and the volumetric wear rate. The linear wear rate, as determined with the shadowgraph technique, was greater in retrieved cups during the first six years postoperatively, but reduced to a lower level in cups retrieved after that time of service.