Three cases of regional migratory osteoporosis.

We examined three patients with regional migratory osteoporosis. Radionucleotide bone scanning and MRI was helpful in the diagnosis of this disease, and all patients recovered with conservative treatment. A biopsy of the femoral head, which was performed in one case, demonstrated bone marrow edema without osteonecrosis. A low intensity area of subchondral bone was observed on a T1-weighted image in two cases, as well as a fracture of the subchondral bone, which might be associated with transient osteoporosis. In one case, the affected region migrated from the medial femoral condyle to the lateral femoral condyle in the same knee joint.