The main symptoms of femoral head necrosis are manifested in the following five points: 1. Pain. Pain can be intermittent or continuous, aggravated by walking activities, sometimes rest pain. The pain is mostly pins and needles, dull pain or soreness and discomfort, often radiating to the groin area, inner thigh, posterior hip and medial knee, with numbness in the area. 2.Joint stiffness and activity limitation. The affected hip joint flexes and extends unfavorably, has difficulty squatting, cannot stand for a long time, and walks with a duck walk. The early symptoms are limited abduction and external rotation activities. 3.Crippling. Progressive shortening limp, due to hip pain and femoral head collapse, or late onset of hip subluxation. Intermittent claudication often occurs in the early stage, and is more obvious in children. 4. Physical signs. Local deep pressure pain, pressure pain at the stopping point of the adductor muscle, positive 4-word test, positive Gagai’s sign, positive A11is sign test. Abduction, external rotation or internal rotation activities are limited, the affected limb may be shortened, muscle atrophy, or even signs of subluxation. Sometimes the axial impulse pain is positive. 5.X-ray performance. The bone texture is thin or interrupted, and the femoral head is cystic, sclerotic, flattened or collapsed.