Central Osteophytes in Acetabulum: Patterns and Importance in Hip Arthroplasty

The posterior of acetabular cup in total hip replacement can be affected by the central osteophytes in the acetabular fovea. We are proposing a classification of such osteophytes based on direct observation and CT scan of osteoarthritis hips. This study was composed of two sections: first 276 cases with all clinical and radiographic evidence of osteoarthritis of hip–with no history of fracture or pelvic bony surgery – were studied by radiographs and CT Scans. The changes in the acetabular osteophytes were evaluated and categorized. Secondly 57 cases of hip osteoarthirites who were undergoing hip arthroplasty received direct observation of the acetabular osteophytes and categorization of the acetabular fovea in accordance with the above classification system. The relation of primary etiology of hip osteoarthritis with the osteophyte classification was also studied. According to radiographs CT Scans and direct visualization four types of acetabular osteophytes were identified. Type I: Normal acetabular with 5mm distance from rim to the floor; type IIa: Evidence of sclerosis around fovea; type IIb: Sclerosis forming a ceiling like an umbrella over the fovea; type IIc: The foveal osteophytes are almost touching in the center; type III: Osteophytes have fully covered the fovea making the acetubular look very shallow. Study and categorization of acetabular osteophytes with radiographs and CT scan would be a helpful pre-operative tool for more accurate reaming of the acetabular cavity and cup positioning in hip osteoarthrties.