Purpose: Although transient osteoporosis of the hip was initially described in pregnant women, now most frequently identified in middle-age and older men. Has also been reported to occur in either hip and in both successively. This condition is referred as migratory transient osteoporosis of the hip. In this study the authors describe five cases of migratory hip osteoporosis and the differential diagnosis with osteonecrosis is also discussed.

Material and Methods: Thirty-four patients with transient osteoporosis were presented. Of the 34 patients five had a similar episode of severe pain in the contralateral hip 14 months mean time later. Early bone scans and MRI of the hips had been carried out in all of the patients. After the evaluation of these findings and thorough exclusion of other conditions diagnosis of migratory transient osteoporosis was demonstrated, and confirmed by the natural course of the disease.

Results: All cases were treated with nonsteroidal anti-inflammatory medications and protected weight-bearing. The course of the disease has not been appreciably altered by medical treatment, and the mean time interval from the onset of symptoms to clinical recovery was 4.6 months (range 3 to 6 months). Imaging findings on MR confirmed the diagnosis during both episodes and paralleled the reduction of pain.

Conclusions: Migratory transient osteoporosis of the hip is a rare self-limited condition of uncertain etiology and pathogenesis, which “migrate” from one hip to the other. Magnetic resonance imaging is highly sensitive in the early detection of this condition and moreover is helpful in the exclusion of other entities. Although the diagnosis is one of exclusion, it must be considered and contrasted with hip osteonecrosis.