Radiographic comparison of grit-blasted hydroxyaptite and arc-deposited hydroxyapatite acetabular components. A four-year follow-up study

High rates of aseptic loosening have been reported for microstructured hydroxyapatite-coated acetabular components. A macrostructured component surface (arc-deposition) not only improves resistance to shear forces experienced by the acetabular component and increases initial stability, but also provides channels for bone ingrowth. The purpose of this investigation was to radiographically compare a series of grit-blasted (microstructured) and arc-deposited (macrostructured) hydroxyapatite-coated acetabular components. A minimum 4-year retrospective radiographic analysis of acetabular components was performed on a total of 50 total hip arthroplasties. At 4 years, arc-deposited components were associated with fewer radiolucent lines in all Charnley zones, particularly Charnley zone III. While the 4-year results for arc-deposited hydroxyapatite acetabular components are superior to their microstructured predecessors, long-term results are still unknown.