Femoral head necrosis is a disease in which the blood supply to the femoral head is interrupted or damaged, causing the death of bone cells and bone marrow components and subsequent repair, which in turn leads to structural changes in the femoral head and collapse of the femoral head, causing joint pain and dysfunction in patients. A, clinical features 1, femoral head necrosis is a progressive disease, without effective treatment, more than 80% of cases will occur within 1-4 years of femoral head collapse, secondary OA, will eventually lead to the complete destruction of the hip joint, seriously affecting the patient’s joint function and quality of life, so that they lose the ability to work, or even unable to take care of themselves; 2, because the age of onset of femoral head necrosis is usually very young, generally in the 20-50 2. Since the age of onset of osteonecrosis is usually very young, usually between 20-50 years old, and 40-80% of patients are involved bilaterally, the disease has a huge impact on patients, families and society because the patients are the main labor force and pillars of their families; 3. Because of the above reasons, femoral head necrosis has attracted widespread attention, but also because of the above reasons people are particularly afraid of femoral head necrosis, invariably fall into a variety of misconceptions. Second, the high risk factors of femoral head necrosis Although the pathogenesis of femoral head necrosis is still unclear, but its causative factors are more clear. The most common reasons are hormone application, excessive alcohol consumption and hip trauma, the most common of which is femoral neck fracture. 1, long-term use of hormones: according to statistics, hormonal osteonecrosis of the femoral head during the last 20 years accounted for 46.03% of all osteonecrosis of the femoral head, so this type of osteonecrosis of the femoral head is extremely common in the clinic. There are some patients suffering from immune diseases, such as systemic lupus erythematosus, rheumatoid, dry syndrome, etc. In some cases, hormones must be applied to control the disease. Clinically, we often find that some patients are “necrosis of the femoral head” because they have certain diseases, such as psoriasis, and blindly believe in the so-called “prescriptions” or “ancestral secret recipes “These drugs may contain hormones, so they may temporarily relieve the symptoms, but over time, not only the original disease is not cured, but also the “femoral head necrosis”. Therefore, the usual hormone or hormone-containing drugs must be applied under the guidance of a doctor, at the same time, do not believe in the so-called “prescription” or “ancestral secret recipe”. 2, alcoholism is a common cause of femoral head necrosis in China, should pay attention to. Moderate drinking can be pleasant and can relieve mental tension, but if long-term, large amounts of alcohol will lead to increased blood viscosity causing bone microcirculation disorders and necrosis of the femoral head. Fracture of the femoral neck can directly affect the local blood supply to the femoral head, leading to necrosis of the femoral head. The literature reports that the chance of femoral head necrosis is 10%-15% for nondisplaced femoral neck fracture and 30%-35% for displaced femoral neck fracture. Patients with femoral neck fractures must go to a regular hospital in a timely manner, without delay, so as not to delay the best time to reset the fracture. Therefore, it can be said that to a large extent, femoral head necrosis is still a preventable disease, less alcohol, avoid hormone abuse is the most direct way to prevent femoral head necrosis, the other, in life, work, pay attention to protection, avoid hip trauma. Third, the main symptoms of femoral head necrosis The earliest conscious symptoms of femoral head necrosis is pain, pain in the groin, hip and thigh area. Early pain starts as hidden pain, dull pain, intermittent pain, more activities increase the pain, rest can relieve or reduce. However, there is also persistent pain with resting pain and nocturnal pain, and the pain gradually increases. At the advanced stage of femoral head necrosis, the femoral head collapses, fractures and deforms, and some of them may cause hip dislocation, and the pain at this time is directly related to hip joint activities and weight bearing. The pain is caused by bony friction within the joint when moving, but the pain is not obvious when there is no friction between the head and socket at rest. Therefore, the early stage of bone necrosis is dominated by pain with functional limitation; the late stage is dominated by functional impairment with pain. At the same time, hip pain and femoral head collapse, or late stage hip subluxation caused by the hip joint caused by the shortening of the hip muscle force arm, hip muscle weakness and the emergence of hip gait.