[Role and place of MRI in the diagnosis of aseptic osteonecrosis of the femoral head. Apropos of 58 pathologic hips].

The early diagnosis of aseptic osteonecrosis of the femoral head has always been difficult. By studying 58 cases, the authors have demonstrated the diagnostic superiority of magnetic resonance imaging. As in the literature, we found aseptic osteonecrosis of the femoral head with no clinical sign, neither radiographic nor scintigraphic, by positive magnetic, resonance imaging. Moreover, it enables the simultaneous study of both hips. It gives with precision the age and extent of the necrosed fragment and enables an absolute differential diagnosis with hip algodystrophy. Magnetic resonance imaging is therefore the second and only examination to be carried out after the standard radiography. The couple, radiography and magnetic resonance imaging, gives all the necessary information for the diagnosis and classification of the aseptic osteonecrosis of the femoral head and Te 99m bone scintigraphy and scanner, whose value was limited, can thus be avoided.