Huang’s eight movements for molding hip joint can have the patient recover early during the repair of the necrotic head. It can mold the hip joint three-dimensionally through biomechanical effect which is generated by the body’s weight compressing the hip joint. This effect is based on stress theory and human anatomy. Through the molding of the hip joint, the acetabulum can be repaired, mechanical performance of the cartilage can be reinforced, density and intensity of unit trabeculae can be improved, osseous structure can be repaired, shape of femoral head can be remodeled, and function of hip joint can be restored. So the eight movements is an effective method with which immobility of the hip joint can be avoided and disability can be reduced.

        Huang’s eight movements for molding hip joint is a major breakthrough for treatment of femoral head necrosis. The traditional theory is a static therapy that includes bed rest, traction, plaster cast, immobilization, wheelchair bound, functional replacement with crutches.

        The shape of femoral head may change because of different forces such as: pulling, compression, shearing, twisting, flexing and so on, exerted on it during movement. This phenomenon is found in animal experiments. The forces received by femoral head are more complex than those exerted on by other joints and the stresses acting on femoral head are larger than those found in other joints. This is called relative stable force received by necrotic femoral head. That is to say that, not only should the hip joint be functionally molded, but also, the femoral head is unable to bear both cornual acceleration and linear acceleration. As a result, the goal of molding the hip joint can be achieved, as well as，the weight bearing stress can be tolerated.

        The course of therapy mainly includes resorption of dead bone, growth of new bone, molding, and repairing. The course is progressed in an open feedback system. In this system, functional repair is progressed according to the requirement of function. The mechanical condition of the hip joint regulates the repair of bone to assist the femoral head and acetabulum in forming new osseous structure which can restore normal function, or nearly normal function. 

During the repairing of bone, a therapeutic environments and conditions that can promote the repair of the head must be created.