Fig. 3

Case 4 (a 49-year-old man). a An anteroposterior (AP) radiograph of the right hip at the time of onset shows the collapse of the weight-bearing region of the right femoral head (arrow). b T1-weighted magnetic resonance image (MRI) shows a low-signal area and low-intensity band (arrow) in the weight-bearing region of the right femoral head. c Preoperative AP radiograph of the right hip in maximum abduction. The arrowhead indicates the lateral end of the fractured area. d Six months after onset, inter-trochanteric curved varus osteotomy was performed. e T1-weighted MRI 2 years postoperatively. The low-signal area that was present preoperatively disappeared. f An AP radiograph taken 6 years postoperatively showed fusion of the osteotomy site and non-progression of the femoral head collapse