Transient osteoporosis of the knee. Case report.

Idiopathic transient osteoporosis is a self-limiting, reversible, and uncommon condition. There is usually an overlap between various clinical syndromes, which includes reflex sympathetic dystrophy and avascular necrosis. This article reports a case of idiopathic transient osteoporosis involving the femur and tibia in the knee following trauma in a 45-year-old man. The diagnosis was confirmed by magnetic resonance imaging. The patient was treated conservatively with bed rest, nonsteroidal antiinflammatory drugs, protected weight bearing, and physiotherapy. He had a full clinical and radiographic recovery.