Ischemic necrosis of the femoral head in children, also known as Perthes disease in children, is a self-limiting disease. It occurs mainly in children aged 2-14 years, with a prevalence age of 4-l0 years. The male to female ratio is 4-5:1 and unilateral accounts for 90%. It is one of the more common and important hip diseases in pediatric orthopedics. The symptoms of femoral head necrosis in children are progressive, with pain, limping and limited movement of the affected hip. In a minority of children, the pain is mild or dull, often in the groin, inner thigh, and radiating to the knee. The prognosis is closely related to the age of onset and the degree of involvement of the femoral epiphysis. In general, the younger the age of onset, the better the prognosis; the less the extent of epiphyseal involvement of the femoral head, the better the prognosis. In the literature, it has been reported that about two-thirds of the patients with natural regression have varying degrees of megaloplasia, and one-third of them have severe hip deformity and early onset of degenerative osteoarthritis. The staging of Perthes disease in children is an important clinical indicator to determine the treatment plan and prognosis. Catterall’s staging method was proposed by Catterall, and is based on the pathological changes of femoral head necrosis, combined with the involvement of the femoral head on radiographs, it is divided into four types. Type I only shows swelling of the soft tissue around the joint and mild outward displacement of the femoral head epiphysis; Type II shows deepening of the femoral head density and flattening of the epiphysis; Type III shows total flattening of the femoral head epiphysis and splitting into small pieces; Type IV shows gradual growth and thickening of the femoral head epiphysis, and the bone density is the same as the adjacent normal bone density, but the femoral head is enlarged, flattened and deformed, and the femoral head is dislocated outward. If there is femoral head fragmentation, femoral neck cystic degeneration and femoral head subluxation, it is called “X-ray crisis” and should be taken seriously clinically. Catterall points out that the prognosis decreases from type I to type IV, and the prognosis of children with types III and IV is usually worse. Non-surgical treatment. Non-surgical treatment is mainly used for children aged <6 years with Catterall types I-II. The methods include bed rest, external booth traction, plaster fixation, abduction brace or orthosis correction, etc. These braces require lower limb abduction of 40°-45° and internal rotation of 10°-15° or no internal rotation in order to obtain inclusion. The hip and knee joints can move independently after wearing the brace, which not only helps to remodel and maintain a good range of motion, but also promotes the flow of synovial fluid and facilitates the nutrition of cartilage and synovial membrane, with good results reported in the literature. Surgical treatment. Surgical treatment is mainly applied to children aged >6-8 years old, children with Catterall stage II-III or above, some stage IV, and children with hip subluxation and clinical danger signs (hip pain and functional limitation). In recent years, with the further understanding of the disease, there is a tendency to take aggressive surgical treatment measures at the early stage of the disease, and the commonly used procedures are pelvic osteotomy and rotational osteotomy of the upper femur. Some possible treatment methods for the cause of the disease, such as drilling and decompression to reduce intraosseous pressure, vascular implantation to increase epiphyseal blood circulation, and synovectomy to relieve joint filling, are not yet well accepted, and the surgical results are not satisfactory.