[Unexplained pain in the ankle and foot. Consider transient osteoporosis]

Transient osteoporosis is an increasingly recognized condition that causes severe pain in weight-bearing joints and is characterized by otherwise unexplained bone-marrow oedema on MRI. We present two patients, a 40-year-old man and a 60-year-old woman, with longstanding severe pain in the foot and ankle. Both had invalidating pain with only mild swelling of the foot or ankle. Laboratory investigation was unremarkable, and conventional X-ray showed osteopenia of the bones involved. In both cases, consecutive MRIs showed migrating bone marrow oedema. The patients were treated with analgesics, immobilization of the body parts concerned and an intravenous bisphosphonate.