CATASTROPHIC FAILURE OF THE POLYETHYLENE LINER OF UNCEMENTED ACETABULAR COMPONENTS

Ten cases are described of catastrophic failure of the polyethylene li ner of three different designs of uncemented acetabular component. Fai lure occurred as a result of either 'wearthrough' to the metal backing , liner fracture or a combination of both, at a mean of 4.6 years afte r implantation (2 to 7.6). At revision there was metallosis in all hip s and osteolysis of the femur or the pelvis in six. Catastrophic failu re was seen only in cups with a minimum polyethylene thickness of less than 5 mm.