If the high density shadow of the femoral head is checked 6 weeks after femoral neck fracture, it means femoral head necrosis, which is generally an abnormal sign. Femoral neck fracture due to the fracture damage to the blood vessels of the femoral head, so the fracture is still facing the possibility of femoral head necrosis after surgery, especially in the middle-aged and elderly population. How to clarify the presence of femoral head necrosis during the postoperative review of femoral neck fracture, generally first review the orthopantomogram of both hips, the femoral head localized hyperdense shadow suspected possible necrosis. When necrosis of the femoral head occurs, generally need to be treated with femoral head replacement or total hip arthroplasty, to avoid necrosis affecting hip joint activities.