BONE REACTION TO UNCEMENTED THREADED POLYETHYLENE ACETABULAR COMPONENTS

One hundred and eighty-one cementless total hip arthroplasties with th readed polyethylene acetabular components, carried out between 1980 an d 1981, have been reviewed retrospectively. Discrepancy between the co mplaints of the patients with loose components and destruction of acet abular bone led to the development of a four stage radiological gradin g system which would enable loosening to be anticipated in routine cas es. There was a high percentage of loosening (33%) in our series and d irect bone-polyethylene contact gave rise to severe granulomatous reac tions around the implants. Strict radiological follow up and early rev ision surgery is indicated in this type of arthroplasty.