Rapid resolution of femoral head osteonecrosis after rotational acetabular osteotomy.

The natural history of osteonecrosis of the femoral head is generally thought to be one of progressive deterioration if no intervention is undertaken. However, it is unknown whether surgical intervention is beneficial for patients with a small region of osteonecrosis. We observed rapid improvement of MRI findings after rotational acetabular osteotomy (RAO) was performed in a young patient with osteonecrosis of the femoral head. The band-like low signal area on T2-weighted images almost resolved by six months after surgery. He returned to work as an electrician by six months after surgery. Early surgical intervention such as RAO that alters the mechanical force acting on the necrotic region of the femoral head may accelerate the recovery of osteonecrosis and the improvement of symptoms.