THE PREVALENCE OF FEMORAL OSTEOLYSIS ASSOCIATED WITH COMPONENTS INSERTED WITH OR WITHOUT CEMENT IN TOTAL HIP REPLACEMENTS - A RETROSPECTIVEMATCHED-PAIR SERIES

The prevalence of femoral osteolysis in hips in which a femoral compon ent had been inserted without cement was compared with that in hips wi th a cemented component, in a retrospective matched-pair study of the results of primary total hip arthroplasties; all patients had received the same type of acetabular component. Forty-one hips in thirty-nine patients who had a Harris-Galante porous-coated total hip prosthesis w ithout cement were matched by age, sex, weight, duration of follow-up, and diagnosis with forty-one hips in thirty-eight patients who had a hybrid total hip reconstruction; the hybrid reconstruction consisted o f the same acetabular component and a Precoat femoral component insert ed with a so-called third-generation cementing technique. All of the o perations were done by the same surgeon, who used the same operative a pproach and the same course of postoperative rehabilitation. All of th e patients were followed for at least four years (mean, six years). Os teolysis developed in twelve (29 per cent) of the hips that had a femo ral component without cement compared with none of the hips that had a cemented component (p < 0.0002). At the latest follow-up examination, none of the femoral components that had been inserted with cement wer e loose and none had been revised, while eight (20 per cent) of the fe moral components that had been inserted without cement were loose and five (12 per cent) had been revised. This retrospective matched-pair s tudy controlled for many of the variables associated with a comparison of the rates of femoral osteolysis in separate series of femoral comp onents fixed with and without cement. The matched-pair study permitted direct comparison of just two factors: the type of fixation of the fe moral component and the femoral component itself. Access of particulat e debris to the periprosthetic interface is essential for the developm ent of femoral osteolysis. The prevalence of femoral osteolysis was si gnificantly higher after the fixation without cement under the conditi ons of this matched-pair study. These data thus support the concepts t hat polyethylene debris has less access to the periprosthetic interfac e after femoral fixation with the third-generation techniques of cemen ting and that that type of cementing provided protection against femor al osteolysis, for the duration of the study, compared with fixation o f the femoral stem without cement.