What are the different stages of femoral head necrosis and how does the treatment strategy differ? At what point is it better to have an artificial joint replacement? The staging of femoral head necrosis is very important, as it reflects the different progression of the lesion and the different pathological changes, and the corresponding treatment modalities are also different. For example, in early stage of femoral head necrosis, when the necrosis has just formed, the pathological changes are not very serious and the shape of the femoral head is relatively good, only some bone changes have occurred inside the femoral head, so it is obviously not suitable to replace the entire femoral head. Surgical treatment, such as drilling and decompression, bone grafting, and strengthening support, can also be chosen to preserve the femoral head. However, in the case of advanced osteonecrosis, the entire femoral head is deformed, forming a serious osteoarthritis with severe and persistent clinical pain, it is difficult to receive results if conservative treatment is chosen. For those patients with osteonecrosis between very mild and very severe, it is a challenging choice for both the patient and the doctor to choose whether to choose a more conservative approach or to choose joint surgery. For example, this patient is over 60 years old, his lesion is not the most serious case, but also not very light, if we take a more conservative approach, do some more conservative surgery, although he may delay for a period of time without joint replacement, but also may not be able to achieve very good results; if you choose artificial joints, may be faster to relieve pain, faster to restore the function of the affected limb, and, modern artificial joints In general, the survival rate of modern artificial joints can reach 85% to 90% after 20 years of use, therefore, we would prefer artificial joint replacement surgery for patients in their 60s. On the contrary, if the patient is very young, for example, in his thirties, he may have to have two or three more surgeries in the future because the artificial joint has a certain life expectancy. Therefore, for young patients, we can choose some relatively conservative methods, including conservative surgery, which is called head preservation (preservation of the femoral head), if the condition allows, in the hope of giving these young or middle-aged people a chance to recover the femoral head. Of course, if the lesion is more serious, including imaging and clinical manifestations, and the patient has tried many methods, but still does not work, and obviously affects daily life and work, even if young, may have to choose artificial joint replacement surgery. Is it possible to reverse mild or stage I femoral head necrosis? I believe that it is possible to reverse milder cases of osteonecrosis of the femoral head, but I cannot say that it is definitely possible. The main approach is to rest, avoid weight bearing such as running and jumping, combined with some medications to improve blood circulation, and some other physical methods. In fact, all these methods are not very specific treatments, that is to say, they are not yet effective for sure, but after all, with these methods of treatment, some of the patients’ symptoms can be relieved and the lesions do not continue to progress in terms of imaging. This is because after the necrotic phase of the femoral head, there will be a repair phase. Therefore, for early stage patients, we would still recommend the approach of preserving the femoral head, although it is not necessarily called reversal, but actually it should be a remission of the lesion and then a slow recovery on this stage, and these cases are actually available in clinical practice. It is just that, so far, there is not a drug or a conservative treatment that has a very positive effect on femoral head necrosis.