The significance of orthopedic surgery is to improve the functional status of the child, to create conditions for rehabilitation training, and to prevent the emergence and progression of deformities. The strategy of lower limb surgery for cerebral palsy is to correct all deformities at once as much as possible, to restore the line of gravity of the lower limbs, to facilitate standing and walking and functional recovery, to reduce surgical pain and more psychological trauma, and this method is called single multilevel surgery abroad. The best age for surgery is when the child can walk and can establish a mature gait, when the child can cooperate well with rehabilitation training, which is conducive to a better recovery. Generally, the age of surgery is after 6 years old, when the bone and joint development is stable and the probability of re-deformation is reduced. 2. A stable, pain-free hip joint with good range of motion is the basic guarantee for walking, and is also necessary for the child to maintain a stable and comfortable sitting position. The goal of hip deformity treatment is to prevent soft tissue contracture and dislocation of the femoral head, to provide a stable, pain-free joint and to improve walking ability. 3. Hip dislocation and subluxation: Children with cerebral palsy who can walk with the aid of a walking device or crutches may develop hip subluxation, while children who are completely unable to walk may develop progressive hip dislocation. The spasticity of the hip adductor and flexor muscles (iliopsoas muscle) is greater than that of the extensor and abductor muscles, and the femoral head is displaced outward and upward, gradually resulting in subluxation of the femoral head. 4. The tilt of the pelvis is related to the dislocation and subluxation of the hip joint, and usually the dislocation of the hip joint and the elevation of the pelvis are on the same side. In addition, contracture of the adductor muscles causes difficulty in walking and sitting, often leading to pathological fractures and difficulty in caring for the perineal area, which requires the release of the adductor and iliopsoas muscles for lengthening. The early weight-bearing of children with cerebral palsy reduces the range of motion of the hip joint, especially the extension, abduction and external rotation are limited, which affects the stability of the hip joint. 5.If the X-ray shows that the hip joint is stable but the acetabulum is shallow or the slope increases, it suggests that the femoral head is poorly covered. It is necessary to reduce the valgus and anteversion angles and to release the contracted adductor and flexor muscles to avoid hip subluxation. In case of hip instability, surgery should be performed as early as possible to stop the progression of the deformity. When acetabular dysplasia and subluxation occur, incisional repositioning, pelvic osteotomy, and rotational inversion osteotomy under the femoral rotor should be performed to reconstruct the concentric relationship of the head and socket. The defect of acetabular dysplasia due to cerebral palsy is mostly found on the posterior side, and excessive rotation can cause the head to prolapse to the posterior side and also block the external rotation of the pelvis. In the past, it was thought that femoral rotational osteotomy should wait until after 8 years of age, before which it was hoped that the excessive anteversion angle of the proximal femur would be corrected by various types of branch growth and development. The anteversion angle does not shape with age, and although the anteversion angle is greater in children with cerebral palsy than in normal children, the cervical stem angle does not increase significantly, so it is thought that orthopedic surgery can be performed at any stage. However, it still needs to be verified in clinical control. 6. The functional neurosurgery team has been focusing on cerebral palsy surgery and rehabilitation for more than 10 years, and has treated tens of thousands of patients, and has taken the lead in establishing advanced three-dimensional gait analysis in China. 7. Our team is currently in contact with top European orthopedic treatment teams for cerebral palsy, actively introducing a hip monitoring system and establishing a database for the assessment of the hip joint and even the entire motor function, so as to relieve the pain of Chinese children with cerebral palsy through scientific and rigorous methods.