Femoral head necrosis, known as aseptic necrosis of the femoral head, or ischemic necrosis of the femoral head, is a lesion caused by localized poor blood flow to the femoral head for a variety of reasons, resulting in further ischemia of bone cells, necrosis, fracture of bone trabeculae, and collapse of the femoral head. The most common symptom is pain, which is located in the hip joint, proximal thigh, and may radiate to the knee. Patients may have impaired movement of the affected limb, or even fracture and loss of joint motion. This disease has many causes, a wide age range and a high disability rate, and is known as the “undead cancer”. Femoral head necrosis can occur at any age, but it is common between 20 and 45 years old. I. What are the main causes of femoral head necrosis? 1, the introduction of hormones and their widespread use, many patients treated with hormones can appear this disease, such as rheumatism, systemic lupus erythematosus, asthma, nephritis, etc. 2, necrosis after aging femoral neck fracture. 3, people’s lifestyle changes, such as smoking, alcohol stimulation are making the number of patients with this disease increased dramatically. Second, how to prevent the occurrence of femoral head necrosis? 1.Change the habit of drinking alcohol in large doses for a long time. 2, avoid the application of excessive doses or long-term improper use of hormonal drugs, if you have to use, you should supplement the intake of vitamins, limit the excessive intake of lipids, you can give a high protein diet, or apply Chinese medicine to regulate the level of lipid metabolism. 3.Avoid strenuous overload sports to minimize the chance of hip injury. 4.Patients with femoral neck fracture should exercise early and weight-bearing late after surgery. Third, will the femoral head necrosis definitely be disabled? Whether the femoral head necrosis will be disabled or not is significantly different from the degree, location and treatment of necrosis. If the extent of necrosis is small, the treatment is timely, and there is no obvious collapse, the possibility of eventual disability can be completely avoided. However, if the patient fails to make a timely diagnosis, takes some hormone-containing therapeutic drugs indiscriminately, or continues to drink a lot of alcohol for a long time and conducts improper activities and exercises, the appearance of extensive necrosis is inevitable. Improper treatment can also lead to collapse. If the femoral head collapses and shatters at a later stage, the femoral head will become flattened, the joint gap will become smaller, the limb will be shortened, the hip joint activity will be significantly limited, and in serious cases, the hip joint function will be completely lost. Fourth, can a non-weight-bearing necrotic femoral head avoid collapse? People’s conventional understanding is that bed rest means no weight-bearing and no stress stimulation can avoid collapse. This understanding is not entirely correct. Because people’s muscles are in a constant state of muscle tone contraction, it can give normal stress between the acetabulum and the femoral head. When patients perform functional exercises in bed, if they perform wrong movements, the compressive stress on the femoral head is obviously increased under the effect of strong muscle pulling, and the femoral head collapses. V. How to perform functional exercise for patients with femoral head necrosis? The functional exercise of patients with femoral head necrosis should implement the principle of combining local and overall, movement and rest, with active activities as the main activity and passive activities as the supplement, and the movements should be coordinated and gradually increased from small to large, from little to much. According to the stage and shape of femoral head necrosis, the degree of functional limitation of the soft tissues around the bone and joint, and the physique, a comprehensive analysis should be conducted to select the appropriate standing, sitting and lying exercise techniques and methods. Generally, non-weight-bearing exercise is the main, supplemented by weight-bearing exercise. Sixth, how should patients with osteonecrosis of the femoral head protect themselves in the event of weather changes? Most patients with osteonecrosis of the femoral head have aggravated their condition and hip pain when the weather changes, and the main reasons are humidity and cold. Humidity can cause dysfunction of skin whistling and metabolism in the hip and leg, resulting in increased microvascular congestion, stasis and exudation due to slow blood flow in local tissues, which aggravates patients’ symptoms. Therefore, in humid conditions, patients should keep their working and living environment dry in addition to appropriate activities to avoid aggravation of symptoms. Cold mainly causes stasis, ischemia, edema and other blood circulation disorders in the hip by constricting the blood vessels in the hip and leg, which aggravates the patient’s condition. Therefore, patients should not sit or sleep in cold places for a long time, and pay attention to more activities and keep warm in winter.