I. Causes of ischemic necrosis of the femoral head The main causes of ischemic necrosis of the femoral head: taking or injecting large amounts of corticosteroids, large amounts of long-term alcohol consumption, smoking, hip trauma, fractures, obesity, etc. These factors lead to ischemia of bone tissue within the femoral head, resulting in necrosis and fracture of bone trabeculae under the femoral head in the high weight-bearing pressure area, lack of bone marrow mesenchymal stem cells in the femoral head to repair and replace aging and dead cells throughout the body, and formation of dead bone, dead cavity and cavity in the femoral head. In the late stage, with the vicious cycle of weight-bearing and ischemia, the femoral head often collapses and osteoarthritis or traumatic arthritis of the hip joint occurs, with knee pain and severe hip pain, and hip joint movement is severely restricted, which seriously affects the patient’s walking and quality of life. Second, PRP treatment for ischemic necrosis of femoral head 1, PRP is the abbreviation of Platelet-rich plasma, Chinese for “high concentration platelet plasma”, which is a high concentration platelet-rich plasma made by using one’s own blood. Human platelets in a highly concentrated state are capable of producing proteins with cell-bonding functions. And when the pH value drops from 7.0-7.2 to 6.5-6.7, the addition of appropriate calcium chloride can promote platelets to secrete a large number of nine growth factors that promote wound and tissue healing and cell regeneration, so PRP is also called “growth factor-rich plasma”. 2.PRP principle (1) Serum provides basic nutrients: amino acids, vitamins, inorganic substances, lipids, nucleic acid derivatives, etc., which are necessary for cell growth. (2) Serum provides hormones and various growth factors: insulin, adrenocorticotropic hormones (hydrocortisone, dexamethasone), steroid hormones (estradiol, testosterone, progesterone), etc. Growth factors such as fibroblast growth factor, epidermal growth factor, platelet growth factor, etc. (3) Serum provides binding proteins: The role of binding proteins is to carry important low molecular weight substances, such as albumin carrying vitamins, fats, and hormones, and transferrin carrying iron. Binding proteins play an important role in cellular metabolism. (4) Serum provides pro-contact and stretch factors to protect the cell wall from mechanical damage. Then add the cell recovery peptide which promotes cell growth to achieve the purpose of osteonecrosis. 3. PRP treatment for osteonecrosis of the femoral head is a new innovation in the field of medicine. Minimally invasive technology Minimally invasive treatment of the osteonecrosis area of the femoral head, removal of dead bone, implantation of autologous or allogeneic bone, compound PRP, promote the formation of new bone, so as to achieve the purpose of reconstructing the blood flow of the femoral head, restoring normal bone structure, preserving the joint and curing osteonecrosis. 4.Safety PRP technology is the use of its own blood to produce a high concentration of growth factor plasma for treatment, does not produce rejection reaction. Soon after its introduction, it was certified by the European CE, SQS and most of the national health departments in Europe, and is widely used in many countries to ensure the safety of its treatment. 5.Autologous plasma with high concentration of platelets and growth factors can be produced in the operating room within one hour with the PRP kit. The PRP kit can produce autologous plasma with higher concentration of leukocytes and growth factors in one hour in the operating room, which solves the disadvantages of long production period, easy infection, low concentration of platelets, lack of maximum effectiveness, and strict restrictions on the hardware and location of production by common laboratory or other methods.