The femoral head is located in the middle of the thigh and is an important part of the hip joint, which is responsible for squatting, standing and walking activities. Ischemic necrosis of the femoral head, also known as aseptic necrosis of the femoral head, is caused by ischemic necrosis of bone cells and collapse of bone trabeculae due to the blockage of the nutritional vessels in the femoral head for various reasons, hence the name “coronary heart disease of the femoral head”. Since the first report of femoral head necrosis, it has become one of the common and difficult to treat chronic diseases in orthopaedic clinics with its characteristics of “long treatment period, high cost and high disability rate”, and is therefore also known as the “undead cancer”. Although the technology of joint replacement is very mature, the overall treatment cost is high and the long-term outcome for young and middle-aged patients is still unpredictable, so joint replacement is the last resort. Therefore, it is very important to preserve the patient’s own femoral head as much as possible, and scientific treatment is the key to improve the outcome, while early diagnosis is the prerequisite for all treatment and prevention. Based on the fact that most patients do not know enough about the disease and do not pay enough attention to it when the pain first occurs early, and it is difficult to accept MRI, X-ray and other examinations, early recognition and judgment of the pain is especially important. Early patients with femoral head necrosis often have no obvious crotch symptoms, and most patients only occasionally feel soreness and discomfort in the lower back, around the root of the thigh or above the knee joint, and the symptoms worsen when walking long distances or carrying weight for a long time, or even limping, but can generally be relieved after rest. The pain may be intermittent or persistent, aggravated by walking activities, and sometimes rest pain. The pain is mostly pins and needles, dull pain or soreness and discomfort, often radiating to the groin area, inner thigh, posterior hip and medial knee, with numbness in the area. It is because the pain is variable, sometimes light, sometimes heavy, and variable that many patients with osteonecrosis of the femoral head miss the diagnosis, misdiagnosis, and miss the time, and even often see the first-time patients that are more serious osteonecrosis of the femoral head, and some even collapse and deformation of the femoral head before they know it is osteonecrosis of the femoral head, leaving lifelong regret. The following is a comprehensive analysis of the characteristics of the pain of osteonecrosis of the femoral head, so that the disease has nowhere to hide! The nerve roots of femoral head necrosis causing pain are on the lumbar 3 and lumbar 4 nerves, and the reflex areas of these two are one in the lumbar area and one in the knee. Femoral head necrosis stimulates the peripheral nerves and radiates to the inner thighs and hip joints, lateral hip and knee joints, especially the role of the foramen ovale nerve is larger, which conducts pain in the internal femoral retractor muscle, quadriceps and knee joint, so it causes pain in the thighs; radiates to the lumbar area This is actually an illusion given by the nerve conduction. Therefore, knee pain and lumbar pain also belong to one of the symptoms of femoral head necrosis. Changes in pain 1. Early stage: Due to bone marrow edema in the femoral head, synovial edema around the femoral head and fluid in the joint cavity, it causes pins and needles, dull pain or soreness around the thigh root, and even cannot cross the legs, wear shoes and socks, lift the legs and ride a bike, causing the whole buttocks to be trapped in pain and thigh weakness, etc. Bed rest, pain medication and hot bath can obviously relieve the pain. In patients at this stage, joint puncture can even extract bloody joint fluid, while under normal circumstances the joint fluid is yellow viscous liquid, and no joint fluid can be extracted by puncture. 2. Mid-term: some bone trabeculae in the femoral head are ischemic, edematous, and fractured, and the degree of pain gradually increases, especially when the pain is more obvious during a day of rest, bed rest, pain medication, and hot bath can relieve the pain, but as long as slightly more activities the pain The pain will be aggravated and the duration of pain will be significantly prolonged. After entering the middle stage, the pain will be relieved by active medication and resting with the help of crutches, and it is easy for some patients to think that “the femoral head is well treated”. Therefore, the pain is reduced, in fact, the femoral head has already started to collapse, at this time should be more vigilant, continue treatment. 3. Late stage: the femoral head gradually collapses and the pain starts to increase again, that is, the patient thinks that “the pain has increased because he is too busy and takes less medication during this period”, but in fact, the cartilage on the joint surface of the femoral head is broken and the subchondral bone starts to collapse, and the “collision” increases when the joint moves. “With the aggravation of collapse, the joint mobility becomes heavier and heavier, and the evolution of femoral head necrosis is completed from the difficulty of forking the leg, to the difficulty of putting on shoes and socks, to the difficulty of squatting, with the pain of the inner thigh tendons and muscles tensing. At this point, all conservative treatment will have no obvious effect, and most doctors’ advice is no longer to recommend various surgical methods to preserve the femoral head, but: go home, prepare and decide to replace the joint! However, if the patient is very young and has good bone condition, it is still possible to make an attempt at bone graft repair and the femoral head collapse can still be corrected through surgery. All stages of femoral head necrosis can lead to pain at the root of the thigh or around it, even if the normal joints are painful due to strain and cartilage damage, etc. This stage is mostly painless, and even if there is pain, it is very mild and will be rapidly relieved after rest and medication. After entering the stage of bone marrow edema and joint effusion, the pain will increase rapidly and the joint function will be significantly limited. Pre-collapse: If the bone marrow edema period lasts for a long time, the bone trabeculae will be compressed by long-term edema and ischemia, and some of the bone trabeculae will be broken, so the pain will gradually increase, but the symptoms can be improved by effective treatment. At this time, there are two directions of development: 1. After surgical or pharmacological treatment such as medullary decompression and bone grafting, the trabeculae will stop fracturing and collapsing, and the pain will be gradually relieved or even painless; 2. The trabeculae will continue to fracture and collapse, and the joint mobility will gradually deteriorate and the pain will be progressively aggravated. In the late stage of femoral head necrosis, the pain is generally severe, and the joint function such as cross-legged, squatting, walking, etc. is limited. In some cases, bone repair and collapse are synchronized, but the joint surface as a whole is better, the bone is compressed after collapse, and the bone in the femoral head is stable. In conclusion, due to the complex etiology of femoral head necrosis, the different pathological characteristics at each stage, the different “experience” of each person’s sensory nerves, and the different processes of collapse after necrosis, the pain in and around the thigh root is not “uniform”; for For patients with similar pain and suspected femoral head necrosis, they should go to the hospital as soon as possible, not to blindly “self-judge”, “Baidu doctors” will not only make people “confused”, but also may put inappropriate treatment The “headline recommendation” of unsuitable treatment methods to “knowledgeable youth” who do not know medicine and love to make decisions through the Internet.