INSUFFICIENCY FRACTURES OF THE FEMORAL-HE AD - CONTRIBUTION OF MAGNETIC-RESONANCE-IMAGING TO THE DIAGNOSIS

Four insufficiency fractures of the femoral head were diagnosed In thr ee women, including two under fluoride therapy. Pain at the root of th e limb and a limp were the presenting symptoms, Serial roentgenograms failed to demonstrate epiphyseal sclerosis; flattening of the head was seen initially or as a residual anomaly in two cases, Radionuclide bo ne scans showed hyperactivity of the entire femoral head, with extensi on to the femoral neck in some instances, suggesting reflex sympatheti c dystrophy and osteonecrosis. Magnetic resonance imaging (MRI) establ ished the diagnosis by showing a linear area of decreased signal inten sity on T1 and T2 images. The outcome was consistently favorable withi n one month of elimination of weight-bearing. The epiphyseal medullary anomalies visible on MRI displays resolved in every case. Residual fl attening of the femoral head was seen in two cases. The two main diffe rential diagnoses are reflex sympathetic dystrophy syndrome and osteon ecrosis.