Geometric variations of acetabular component design and its effect on radiographic osseointegration

The Reflection uncemented acetabular component (Smith & Nephew, Memphis, Tenn) for total hip arthroplasty is available in 2 geometric variants. The first has a completely hemispherical design; the second has a peripheral rim expansion designed to increase initial press fit and aid osseointegration. The clinical and radiologic outcomes of 527 consecutive primary total hip arthroplasties were reviewed to investigate the differences in component design. Of the components, 95.6% survived at 96 months with revision for aseptic loosening as the end point, with no significant difference between the 2 component designs. Eighty percent of hemispherical and 57% of peripherally expanded components were considered completely osseointegrated at final radiologic review. The midterm radiologic outcome of peripherally expanded acetabular components is inferior to that of a completely hemispherical design.