Unusual osteonecrosis of the femoral head misdiagnosed as a stress fracture.

We report a case of femoral head osteonecrosis that originally was misdiagnosed as a femoral neck stress fracture by plain radiography and magnetic resonance imaging. The correct diagnosis was made using pinhole bone scintigraphy, which revealed a completely cold lesion of the entire femoral head, confirmed by histologic examination. The patient was treated with muscle pedicle bone grafting, and 3 months postoperatively, pinhole bone scintigraphy showed improved vascularity of the femoral head.