Insufficiency fractures of both femoral necks in a young adult caused by osteoporosis: a case report.

Insufficiency fractures of femoral necks due to osteoporosis of unknown aetiology occurring coincidentally on both sides in young adults, have not been described in English literature so far. A 18-year-old young girl presented with a 3-month history of gradual onset of bilateral thigh pain and progressive inability to walk. At the first look, plain radiographs of both hips showed no gross abnormal findings other than some tips on reduced bone mineral density of the femoral necks. MRI was ordered upon a high suspicion of fracture and T1-weighed MRI showed a linear low signal on both femoral necks. Dual-energy X-ray absorptiometry of the lumbar spine and femoral neck showed low mineral density. She was treated surgically with in-situ internal fixation using cannulated screws. The bilateral thigh pain was resolved and walking started immediately after the treatment. Insufficiency fracture of the femoral neck due to osteoporosis should be kept in mind even in young adults complaining of atypical pain without evidence of unusual activities. We used both the terms of stress fracture and insufficiency (osteoporotic) fracture interchangeably as the mechanism of fractures resemble each other.