[Fractures caused by bone insufficiency of the proximal femoral epiphysis. Contribution of MRI].

The fractures by bony insufficiency are particularly well seen on MRI. On T1 weighted images they are detected as a very hypointense line surrounded by a hypointense area. On T2 weighted images, the hypointense line is also recognized and represents the fracture surrounded by a hyperintense area due to oedema or hemorrhage. Five cases of bony insufficiency fracture of the femoral head are reported. The features of the superior subchondral locations of these fractures and some primary and limited epiphyseal osteonecrosis are similar and consistent with a common pathogeny.