1, the so-called osteonecrosis is regardless of any reason to interrupt the nutrition of bone tissue, bone cell death that occurs bone necrosis. Osteonecrosis is a process, not the same as dead bone. Dead bone is one of the end of osteonecrosis, it has completely lost its activity and separated from the normal bone tissue, the boundary between the two is clear, it has become a foreign body in the bone, osteonecrosis is divided into two categories: one is caused by bacterial infection caused by osteonecrosis. Such as osteomyelitis, bone tuberculosis, etc., can cause inflammation, necrosis, resorption, separation of bone tissue, ~ part of the formation of dead bone. Another type of osteonecrosis is caused by ischemia. The nutrition of human bones, muscles, nerves, organs and all tissues and organs is carried by blood, where the blood is insufficient, it means where the nutrition is lacking, without nutrition, necrosis will follow, this kind of necrosis is called ischemic necrosis. Necrosis occurs in the absence of bacteria and is also called aseptic necrosis. Osteonecrosis can occur in many parts of the body, occurring in the femoral head is called ischemic necrosis of the femoral head. 2.What is combined Chinese and Western medicine treatment for ischemic necrosis of the femoral head? The traditional theoretical system of Chinese medicine is applied to guide clinical practice and introduce the advanced technology of Western medicine, which is applied to the treatment of ischemic necrosis of the femoral head. Specifically: for ischemic necrosis of the femoral head, the identification of the evidence is combined with the identification of the disease, and further combined with the staging and typing, etc. For early stage patients, the main treatment is Chinese herbal medicine, and for middle and late stage patients, the treatment is surgery with Chinese herbal medicine and rehabilitation, which we call combined Chinese and Western medicine treatment for ischemic necrosis of the femoral head. It reflects the principle of combining dynamic and static, and treating both the symptoms and the root cause. 3.What factors are related to ischemic necrosis of the femoral head? There are many factors that cause ischemic necrosis of the femoral head, about forty kinds, which are summarized into two categories: traumatic and non-traumatic. The trauma category includes femoral neck fracture, hip dislocation, slipped femoral head epiphysis, acetabular fracture and intertrochanteric fracture. The non-trauma category includes hormone therapy, alcoholism, decompression sickness, hemoglobin disorders, Gaucher’s disease, radiation therapy, pancreatic disorders, hyperuricemia, atherosclerosis, sickle cell disease, connective tissue disease, lipoprotein abnormalities, Cushing’s disease, osteogenesis imperfecta, venous disorders, iron toxicity, diabetes, bronchial asthma, mucopolysaccharide metabolic disease, osteoporosis, osteochondrosis, high-altitude disease, pregnancy, leukemia Hemophilia, hemophilia, etc. 4.How is the mechanism of ischemic necrosis of femoral head? The mechanism of ischemic necrosis of the femoral head has been studied for more than 100 years, and scholars at home and abroad have unanimously recognized that ischemia of the femoral head is the main pathogenesis of necrosis. However, it may occur from the arterial blood supply, can be caused by poor venous return, or due to the increase of intraosseous pressure resulting in ischemia and necrosis. It can be subdivided into: (l) extraosseous factors: Femoral vascular dissection and compression due to trauma, vasculitis, vascular obstruction due to atherosclerosis, Raynaud’s disease, decompression sickness and vasospasm due to sympathetic reflexes can directly or indirectly lead to ischemic necrosis of the femoral head. (2) Intraosseous factors: abnormal red blood cells of hemoglobinopathy, nitrogen emboli of decompression disease, alcoholism and fat emboli produced by pancreatic diseases can block the microvessels in the bone, leading to ischemic necrosis of the femoral head. In addition, the accumulation of abnormal red blood cells in Gaucher’s disease, metastatic tumors, and the increased volume of bone marrow contents caused by hormone-induced hypertrophic adipocytes can lead to increased pressure in the bone marrow cavity and compression of the intraosseous microvasculature or lesions or spasm in the bone itself, resulting in obstruction of blood supply. Various pathogenic factors inside and outside the bone can increase the intramedullary pressure, and the increased intramedullary pressure increases the resistance to blood flow, which further leads to ischemia, cell degeneration and necrosis, and edema. The edema of the tissue further increases the increased intraosseous pressure, forming a series of vicious circles, especially when the affected limb continues to bear weight, increasing the pressure on the ischemic femoral head, which will accelerate bone necrosis and lead to the fracture of bone trabeculae and the collapse of the femoral head.