Femoral component loosening using contemporary techniques of femoral cement fixation

Abstract

A radiographic study was performed on 171 total hip arthroplasties that had been followed up for an average of 3.3 years (range, 2-5 years). The study was undertaken to assess the incidence of loosening of the femoral component in older adult patients (average age, 60 years) in whom the medullary canal had been plugged with methylmethacrylate before introducing the cement (Simplex P) with a cement-gun. The majority of femoral components used were of the CAD or HD-2 design, and all were made of chromium-cobalt alloy. Three categories of loosening were defi ned: defi nite (requiring radiographic evidence of migration of the component or the cement), probable (requiring evidence of complete 100 % radiolucent zone around the cement mantle on one or more radiographs), and possible (requiring evidence of a radiolucent zone that occupied more than 50 but less than 100 % of the cement-bone interface on one or more radiographs). One hip required revision for a loose femoral component and another patient had asymptomatic subsidence of the femoral component. Therefore the total incidence of defi-nitely loose femoral components was 1.1 %. No hip was classifi ed as having probable loosening; 7 hips (4 %) were graded as having possible loosening. Compared with the results of four other published reports of patients of similar age with similar follow-up, and using the same radiographic criterion for loosening, the current series demonstrated a statistically signifi cant reduction in the incidence of defi nitely loose femoral components.