Femoral head necrosis after extracapsular fracture is a rare complication.Until now, we have experienced only one case of femoral head necrosis after CHS operation. Three months later, the patient complained of hip pain when walking, and radiograph 10 months after operation showed a penetrated rag screw. The cause of fracture was simple fall that was not high energy accident. The vascural anastomotic ring at the base of the femoral neck plays an important role in the circulation of the femoral head. In this case, a possible etiology was the iatrogenic damage of blood supply to the femoral head (due to rotational force applied to the femoral head during reaming). It is therefore important to use a dase pin during operations.
