Fig. 1

a Preoperative plain AP X-ray of left hip demonstrating a Stage IIa osteonecrotic lesion. b MRI T1-weighted coronal image of left hip shows a geographic pattern of the necrotic area
a Preoperative plain AP X-ray of left hip demonstrating a Stage IIa osteonecrotic lesion. b MRI T1-weighted coronal image of left hip shows a geographic pattern of the necrotic area