The hemipelvis: an unusual site of osteonecrosis. A report of two cases.

Osteonecrosis or aseptic necrosis is well-recognised in certain sites. We report two patients, both with predisposing factors, who developed avascular necrosis of the hemipelvis which was bilateral in one case. In each patient the diagnosis was not suspected clinically. In the initial phase, bone scintigraphy showed diminished uptake in the hemipelvis when plain radiographs were normal. Follow-up scans showed evidence of revascularisation. This is an unusual site for osteonecrosis, though there appears to be an underlying anatomical basis for its occurrence.