Lesson Learned From Retrieval Analysis Of A Dislocating, Large Diameter MoM Revision THA - A Case Report

Wear debris generated by a total hip arthroplasty (THA) bearing can cause considerable damage to the surrounding soft tissues and bone, compromising patient function and causing long-term pain. In the case of a traditional bearing, a metal (or ceramic) head articulates with an ultra high molecular weight polyethylene (UHMWPE) cup. The polyethylene debris generated is processed by the macrophage, and through a cascade of cytokines, results in an inflammatory response. The inflammatory response causes a surrounding toxic reactive synovitis 7 . Frequently an associated pronounced osteolysis phenomenon occurs, compromising implant fixation 6 . The significant bone loss makes subsequent revision THA very difficult and can affect long term implant survival. The severe osteolysis seen with UHMWPE bearings prompted many surgeons to utilize alternative bearing constructs such as metal-on-metal, metal-ceramic, and ceramic-ceramic bearings.