DIFFERENCES IN POLYETHYLENE WEAR BETWEEN CERAMIC AND METAL ON POLYETHYLENE HIP PROSTHESES - A BIOPSY AND POSTMORTEM STUDY

Pseudocapsules of artificial hip joints with ceramic- and metal on polyethylene combination of the articulating surfaces from 126 revision arthroplasties and 41 autopsies were studied histologically with semiquantitative evaluation of the polyethylene wear. The results were compared with reports of laboratory tests in the literature. We found in the autopsy specimens as well as in the biopsies from revision arthroplasties of prostheses implanted for 4 to 8 years three times less polyethylene wear particles released from the ceramic on polyethylene prostheses. The newly established synovium surrounding prostheses with ceramic heads appeared 20% reduced in thickness with minor villous transformation. Different types of metal on polyethylene prostheses revealed no differences in wear behaviour with the exception of the bipolar prostheses which showed a markedly increased polyethylene wear.