Normal intra-femoral head pressure averages 18 mmHg, while osteonecrosis reaches 61 mmHg. Medullary core decompression is a surgical treatment commonly used to treat femoral head necrosis designed based on this pathology. The aim was to increase the repair of the necrotic area, however, this repair was later proven to be imperfect, one of the main factors was that as the blood flow of the femoral head necrosis was reconstructed during the repair process, the rate of bone breakdown and bone resorption was often greater than the formation of new bone, and marrow core decompression further weakened the mechanical support of the already weak subchondral bone, especially in hormone-induced ischemic necrosis of the femoral head, where osteoporosis is obvious and marrow Core decompression leads to stress concentration and causes femoral head collapse. Medullary decompression alone cannot prevent or correct the femoral head collapse, but will accelerate the collapse of the femoral head. Therefore, various methods have emerged to treat femoral head necrosis, such as: medullary decompression lesion removal + bone flap implantation with (or without) vascular tip, etc. However, the traditional medullary decompression + bone flap implantation with vascular tip is long, bleeding, complicated surgical operation, and requires longer postoperative immobilization, which prevents functional exercises from being performed in the early postoperative period and is not conducive to the patient’s recovery. Drilling decompression with autologous iliac bone grafting is less invasive, shorter operation time, less bleeding, and does not require long postoperative immobilization, so functional exercises can be performed in the early postoperative period, and patients have good recovery results. For patients with early stage, collapsed femoral head <2mm, drilling decompression with autologous iliac bone grafting is used. The advantages of this procedure are that marrow core decompression can reduce the excessive pressure in the femoral head and improve the blood flow of the femoral head; drilling and bone grafting also play a mechanical role in promoting the revascularization of the necrotic femoral head, and have the effect of preventing the collapse of the femoral head. After decompression, the closed bone marrow cavity was opened and the high pressure caused by ischemia in the bone was then relieved, which stimulated the regeneration of capillaries and the formation of bone trabeculae, improved intraosseous venous return and increased blood supply, and the process of femoral head regeneration was started, and the intraosseous circulation was reestablished, thus improving the The strength of the femoral head; bone grafting can effectively repair bone defects, promote bone healing and regeneration, and provide effective mechanical support, which can prevent or delay the collapse of the femoral head and can delay the age of artificial joint replacement in young and middle-aged patients.
A subtle enlargement reducer of the femoral head, through a bone hole (about 10 mm), reaches inside the femoral head and removes the necrotic bone. The advantage is that the dead bone inside the head can be removed according to the specific situation of femoral head necrosis, and its removal diameter can reach 30 mm without destroying the surface structure of the femoral head, without cutting the joint, and the diameter of the medullary tract hole opened through the greater trochanter is small, causing less damage to the patient, providing a The small diameter of the medullary foramen through the greater trochanter provides less damage to the patient and provides a practical treatment for femoral head necrosis. Moreover, it has no impact on the later treatment.