BONE-MARROW EDEMA - AN EARLY FORM OF NECR OSIS OF THE HEAD OF FEMUR

We examined 15 patients (16 hips) with painful hips whose radiographs were either normal (n=9) or showed a minimal decrease in radiodensity (n=7). The available bone scintigrams of 9 cases were positive. T1-wei ghted images visualised a diffuse signal loss of the bone marrow in al l hips, with various extensions in the head, neck, and intertrochanter ic area. These regions were hyperintensive on T2-weighted images. Foca l anomalies were not seen in any of the cases. All patients underwent core decompression treatment. Histology of 13 hips confirmed not only the presence of bone marrow oedema but of bone changes corresponding t o those of avascular necrosis. Follow-up examinations with MR after co re decompression showed normal signal intensity in all cases. Magnetic resonance represents a viable diagnostic tool for identifying bone ma rrow oedema. Due to our histological results bone marrow oedema should be included in the differential diagnosis as an early stage of necros is of the hip.