1.What is ischemic necrosis of the femoral head in children Ischemic necrosis of the femoral epiphysis in children is Perthes disease, which was reported by American scholar Legg, French scholar Calve, and German scholar Perthes in 1910, so it was also called Legg- Calve- Perthes syndrome, referred to as Perthes disease. Perthes disease is one of the common orthopedic problems, mostly seen in children aged 2 to 12 years, with those aged 4 to 8 years being more common. The characteristic changes of this disease are different degrees of ischemia and necrosis of the femoral head, which often leaves different degrees of deformity and joint dysfunction in the later stages, and may develop into early osteoarthritis. 2.Why do you get ischemic necrosis of femoral head in children and what kind of people are prone to the disease It is usually believed that trauma leads to injury and rupture of blood vessels inside and outside the bone, thus causing impaired blood supply or return flow, which is the earliest and most definite cause of femoral head necrosis found, including femoral neck fracture, dislocation of femoral head, slipping of femoral head after epiphyseal trauma, compression fracture of femoral head and other factors. In addition, it is also related to infection, congenital malformation, increased pressure within the femoral head neck bone, lack of nutrition in the articular cartilage, periprosthetic lesions, use of hormones, passive smoking, etc. 3, what are the symptoms of ischemic necrosis of femoral head in children Main symptoms and signs: (1) hip, groin pain or knee pain, obvious when running and jumping, reduced at rest; there is obvious night pain and cramps; (2) plainly like sports, parents (2) Occasionally found limp, intermittent; (3) examination of the affected hip has pressure points, and the movement of the hip joint in all directions is limited to varying degrees; (4) thigh muscle atrophy may appear in those with a history of more than 1 year. 4. What kind of examination is needed When there are risk factors, such as pain in the knee, hip or groin area and limitation of hip movement, although the x-ray findings are normal, Perthes’ disease should be highly suspected for follow-up observation and regular bilateral hip orthopantomogram and frog x-ray should be taken to detect subtle changes at an early stage. Bone scan can indicate the occurrence of osteonecrosis at an early stage, and for those who have symptoms on one side and the x-ray does not show changes, bone scan is feasible. CT scan is more specific and sensitive than x-ray, especially when the x-ray has not yet shown significant abnormalities, and CT is more suitable for the early diagnosis of osteonecrosis. For middle and late stage lesions, CT can clearly and accurately show the three-dimensional orientation, scope and extent of the lesion, in order to prevent the development of the disease and develop a treatment plan MRI is the most accurate imaging technology for the diagnosis of ischemic necrosis of the femoral head, but due to the high price, it is not as good as x-ray in the continuous observation of Perthes disease. 5.How to treat ischemic necrosis dislocation of femoral head in children and what are the conservative treatment measures The treatment outcome of this disease depends largely on whether it can be detected and treated early. Non-surgical treatment methods mainly include abduction and internal rotation walking brace, weight-free brace or plaster fixation, which are mainly suitable for early patients. After the cast is removed, the child should be instructed to exercise the hip and knee joints in bed for 2-3 months, and then gradually get out of bed for functional exercise, and prohibit strenuous exercise for 1 year. The child should come to the hospital for review once every 3 months to 6 months. The advantages of surgical inclusion therapy are that the child can start functional exercises and resume normal activities earlier after surgery, which is conducive to the shaping of the femoral head, and the inclusion of the femoral head is permanent. Myotibial flap graft, vascular flap graft, and vascular flap graft.