Ten years of experience with porous acetabular components for revision surgery

A prospective study was completed for 139 porous-coated revision acetabular components that were implanted with rim fit fixation and had a mean of 4.3 years' followup (range, 2-9.8 years). The Anatomic Porous Replacement component was studied. Harris Hip Scores were used for clinical evaluation, and the pain and limp components of the Harris Hip Score were assessed. Radiographic measurements were recorded as radiolucent lines by Delee and Charnley zones. Clinical results were of lesser value in this study because of the emphasis on the acetabular component. Of these components, 4.3% had revision; only 2 (1.4%) were revised for loosening. Migration occurred in 2.1% of these acetabular components. In the first 2 years postoperatively, 17.4% of components had increased radiolucent lines and 9.4% had fewer radiolucent lines. After 2 years, fixation was stable: 4% had progressively more radiolucent lines and 2% fewer radiolucent lines. The authors could not show any statistical difference in radiographic fixation of these components when adjunctive screw fixation was used or not used. Fixation of the acetabular components was better when slurry bone graft was not used to layer the acetabular surface. Fixation was similar whether the rim fit was obtained with or without protrusion of the medial dome of the cup into the pelvis. The authors did not observe osteolysis in the acetabular bone surrounding these components.