Abstract
We microscopically investigated the periprosthetic tissue reaction to wear debris arising from the metal on metal total hip replacements (THR) and compared our findings with that occurring in polyethylene cases. McKee-Farrar prostheses were revised in 4 cases 13 to 20 years after first insertion, providing the opportunity to investigate the accumulated granulation tissues around the prostheses. Much less volumetric, and over all smaller diameter wear particles were observed in the metal on metal THR, cases which caused milder and less intense tissue histiocytic reactions, particu-larly multinucleated giant cells, compared to that in the metal of polyethylene cases. Interleukin-1 and -6, which play an important role in osteolysis were also seen much less in the metal of metal THR.
