Fig. 1

a Initial radiograph showing bilateral femoral neck fracture (arrows). The osteosclerotic lesion was observed at the right acetabulum (arrowheads). In the left hip, the cross-over sign was seen (dotted lines). Coronal T1-weighted image (repetition time/echo time [TR/TE] = 474/14 msec) showing diffuse low-signal intensity in the femoral head and lower neck (b) and the corresponding high-signal intensity on the T2 fat-saturated image (TR/TE = 3500/87) (c). Coronal T1 (b) and T2 fat-saturated (c) images revealed the fracture line in the bilateral femoral neck (arrows) and in the right subchondral region of the acetabulum (c) (arrowheads). d Bilateral osteosyntheses using multiple pinning method were simultaneously performed in the bilateral hips