POROUS-COATED ACETABULAR COMPONENTS WITH SCREW FIXATION - 5 TO 10-YEAR RESULTS

The results of 136 consecutive primary total hip arthroplasties perfor med by one surgeon with the Harris-Galante-I porous-coated acetabular component were reviewed at a mean of seven years (range, five to ten y ears). In all hips, the outer diameter of the acetabular component was the same as the diameter of the final reamer used in the preparation of the acetabulum. However, this reamer was used only briefly at the r im of the acetabulum, and therefore the components had so-called press -fit stability. A mean of four screws (range, three to six screws) wer e used for additional fixation of the component. The clinical evaluati on was performed with use of the Harris hip score. Standardized antero posterior radiographs of the pelvis were assessed for migration of the component, radiolucent and radiodense lines, linear wear of the polye thylene, and osteolysis. No acetabular component had been revised for loosening and none were radiographically loose at the time of the most recent follow-up evaluation. There were no complications related to t he use of the screws, and no screw had bent or broken. A non-progressi ve radiolucent line was seen in one acetabular zone in thirty-four hip s (25 per cent) and in two acetabular zones in six hips (4 per cent). No hip had a radiolucent line in all three acetabular zones. The mean rate of linear wear of the polyethylene was 0.1 millimeter per year. T here was no dissociation of the acetabular liner from the metal shell. Two hips (1 per cent) had asymptomatic osteolysis in the ischium and adjacent to the rim of the acetabular component; this was treated with grafting at the site of the lesion and exchange of the femoral head a nd the worn polyethylene liner. Five femoral components inserted witho ut cement and one inserted with cement were revised because of looseni ng. The data suggest that, at a mean of seven years, fixation of this porous-coated component was uniformly excellent. The low prevalence of radiolucent lines and the absence of loosening are probably related, in part, to the technique of implantation. The low prevalence of polye thylene wear and pelvic osteolysis is a notable improvement compared w ith the results of arthroplasty with other porous-coated acetabular co mponents. Although the results of the present study are encouraging, l onger follow-up is necessary to determine the prevalence of late loose ning and osteolysis.