The hip joint it is a pestle and mortar joint, the acetabulum is like a bowl and the femoral head is like a pestle and mortar. It is one of the joints with the largest range of motion in the body, of course the largest joint is the shoulder joint, but the range of motion of the hip joint is also very large. The total range of motion of the hip joint can reach 240 to 300 degrees, with 120 to 140 degrees of flexion and extension, 60 to 80 degrees of extension, and 60 to 90 degrees of internal and external rotation, which is the normal range of motion. This is the normal range of motion. For example, walking on a flat road, we need 50 to 60 degrees, while wearing shoes and socks, we need 160 to 180 degrees. What exactly is the stress on the hip joint for surgery? Normal walking is 2.7 to 4.3 times the stress of body weight, then up steps reach about 3.4 to 5.5 times, then down steps are 3.9 to 5.1 times. The most common classification of diseases of the hip joint can actually be divided into three categories. One is ischemic necrosis of the femoral head, which is of course the early stage, and the late stage where he finally develops osteoarthritis of the hip joint. In addition, in our country is also more common is hip arthritis, including rheumatoid arthritis, including ankylosing spondylitis, especially ankylosing spondylitis caused by the hip joint this disease is very common. The most common is of course hip osteoarthritis, because all joints can be classified as hip osteoarthritis for any reason other than inflammatory arthritis that causes joint ankylosis and other late changes in the hip joint. The most common type of femoral head necrosis is traumatic, such as femoral neck fracture, and no matter how you treat the femoral neck fracture, about 1/3 of the patients end up with femoral head necrosis. In addition, non-traumatic necrosis is mainly caused by alcoholism or the use of hormonal drugs, which accounts for more than 80% of the total non-traumatic necrosis of the femoral head in our country. The remaining rare diseases such as hyperuricemia or diabetes, obesity can cause it, and even pregnancy can cause it. If we find out the cause of the femoral head necrosis, we call it primary necrosis. There are two common stages of ischemic necrosis of the femoral head, one is the common coarse stage called Ficat stage, which is divided into stage 0, 1, 2, 3, and 4. stage 0 means that there are pathogenic factors, for example, the patient has taken hormones or long-term alcohol abuse, but clinically there are no symptoms and various tests are normal, some people in this case have done some decompression of the medullary cavity and follow up with cardiac decompression. But this is a little bit far-fetched, but we are commonly divided into stages 1, 2, 3 and 4. In stage 1, the patient has symptoms, but the X-ray is normal, and the MRI, isotope and CT examinations may be abnormal. In stage 2, there are changes in the trabeculae on the X-ray, but the femoral head is not collapsed. In stage 3, the femoral head will collapse, but the osteoarthritis is less severe and the morphology is still basically normal. In stage 4, the collapse of the femoral head is very obvious, and the osteoarthritis is obvious. The more accurate staging is related to our scientific research or we use the International Society of Bone Circulation staging, also called ARCO staging. It is also divided into 01234 stages, depending on the clinical examination methods and the size of the lesion, which is more detailed. This clinical staging is basically similar to the Ficat staging. However, the subtypes of this ARCO staging are more emphasized. For example, the area of involvement is classified as less than 15 for mild, 15% to 30% for moderate, and more than 30% for severe. The length of the meniscus and the depth of the joint surface collapse are all possible, which are the characteristics of his staging. We should pay special attention to the fact that this staging is based on sagittal staging, so if you want to do scientific research on femoral head necrosis, to determine the severity of necrosis before surgery, please make sure to do the sagittal plane when you do the MRI. Then the diagnosis of necrosis should be paid special attention, because our country is always diagnosing the femoral head paradigm, that is to say, not osteonecrosis is also diagnosed as osteonecrosis. If the MRI shows a homogeneous change of bone marrow signal, instead of a regional and focal change like real osteonecrosis, it is a hip edema syndrome, or also called a transient osteoporosis of the hip joint. The non-surgical treatment of femoral head necrosis is mainly patient education, in fact, his prognosis is mainly related to the area of necrosis, necrosis area is very large how you treat, sometimes it is difficult to get the best to achieve the best results. If the necrosis area is small, you don’t need to treat it. Therefore, patient education is very important. At the same time, no weight-bearing, such as cycling, swimming and so on. Medications mainly include painkillers and Chinese herbs, which have a certain effect of relieving the blood circulation, but never, never expect that Chinese herbs can cure femoral head necrosis, because it is impossible, but only improve it. Then physical therapy can also be used to improve the symptoms of femoral head necrosis. What are our current misconceptions about femoral head necrosis? First of all, some people think that femoral head necrosis expands with the progress of the disease, for example, when I found the area is like this, may not three months later the area will expand by one third or double? In fact, the area of femoral head necrosis does not expand with the progression of the disease, it mainly depends on the size of the necrosis at the beginning, such as the early stage. But if the area of necrosis is small, he does not affect the body’s weight-bearing, he will not cause any dysfunction, and may slowly heal on his own. Therefore, the area of necrosis does not increase with the progression of the disease. Secondly, it is wrong to say that cystic changes of the femoral head are a sign of femoral head necrosis, because cystic changes of the femoral head can occur in any hip joint disease, and they are not the only characteristic changes of femoral head necrosis. Then we hope to intervene at an early stage because most of these patients are young, so that we can achieve some hip preservation treatment. And then delay the time of femoral head collapse and artificial joint replacement as much as possible. In fact, this kind of worldwide plus many doctors in our country have made a lot of efforts, then it boils down to early stage mainly through drilling decompression or drilling decompression plus bone graft surgery or allogeneic bone compression bone graft surgery, etc. These are many similar or variant methods. Then in the middle stage, there are considerations such as collapse, so for example, like the Japanese who do osteotomy. In the late stage, we do artificial joint replacement, including very rare patients we can consider joint fusion and head and neck resection. Drilling and decompression of femoral head necrosis. In fact, drilling decompression can play a very good role in reducing the intraosseous pressure in the femoral head of the hip joint and relieving the increase of intraosseous pressure. In other words, it has a good pain relief effect, and the early pain relief effect is good. However, if the patient is not in particular pain, then generally he does not have much effect because he has no supporting effect. Some of our doctors try to use allograft or autologous fibula graft with blood vessels, but it is true that the supporting area of the femoral head is too small to achieve the therapeutic effect and prevent the hip joint from collapsing sometimes. Mid-term osteotomy was first invented by the Japanese, but it is a very difficult operation, and the results of other people replicating this operation do not always reach the Japanese results, and because of the uncertainty of the results of this operation, it has not been carried out worldwide. There is another method that we are currently using, which is deep cryogenic frozen allograft bone compression implantation. The procedure is to remove the necrotic bone completely by grinding and drilling, and after the normal bone bed is clearly revealed, the allograft bone is driven into the femoral head to play a supporting role.