The principle is early detection and correct treatment in a timely manner. Studies have shown that the concentric head and socket are the basic conditions for the development of the hip joint. The femoral head should be allowed to return to the acetabulum as early as possible so that both can develop normally. Treatment is required before weight-bearing to prevent secondary arthropathy. The treatment plan is determined by the age of the child. If detected before weight-bearing walking, non-surgical treatment is available, with mostly good results. If detected too late, surgical treatment is required and recovery is often incomplete. Non-surgical treatment 1. Total dislocation within 6 months after birth Most of the hips can be repositioned by abducting the hip joint. But should be long-term follow-up. 2, <3 years old subluxation Long-term use of abduction urinary pillow or abduction brace can be expected to be cured. If not cured, extra-articular iliac osteotomy can be performed at the age of 4-6 years. 3.Full dislocation from 7 months to 3 years old Most of the dislocations can be cured by repositioning and plaster fixation. If the local soft tissues are stiff, it is advisable to use skin traction for 2 to 3 weeks first. If the adductor muscle is tense, the adductor muscle can be cut first, and then try to reset by manipulation under anesthesia. The repositioning technique should be gentle and avoid violence to prevent fracture of the femoral neck and epiphysis injury. After confirmation of the repositioning by radiograph, a frog cast is used, i.e. 90° of hip and knee flexion and 60-70° of abduction. Note: Aseptic necrosis of the femoral head can occur with excessive abduction. After 3 months of fixation, the cast was removed and X-ray examination was performed, and if the repositioning was good and stable, the cast was changed to 50° of abduction of both hips and straightening and internal rotation of both legs. After 3 months of fixation, remove the cast and take X-ray film for review, if the position is stable, switch to abduction brace fixation. 3 months later, remove the brace for 1 to 2 hours every day to practice walking, and insist on wearing the brace at other times, do not be too hasty and put too much weight on it. During the treatment period, the patient should be reviewed regularly and X-rays should be taken every 3 months to observe the repositioning situation and the presence of femoral head necrosis. Surgical treatment For children over 3 years old (the manual reset is unsuccessful) and for those under 3 years old who fail in the manual reset, surgical treatment should be performed. Before surgery, bone traction should be made on the upper tibia (under 3 years old can be skin traction), traction weight is 1kg for 1 year old, generally not more than 6-7Kg, traction time is 3-4 weeks, so that the femoral head reaches the acetabular plane before surgical reset. 1.Simple incisional repositioning is suitable for those who fail to reposition manually at the age of 1~2 years. After the operation, one and a half hip herringbone cast is fixed, keeping the affected hip abducted 30°, flexed 20° and internally rotated 30° to keep the center of the femoral head repositioned. 4-6 weeks later, the cast is removed, that is, non-weight bearing activities are started in bed, and skin traction can be applied for a short time to facilitate the recovery of joint mobility. 2.Iliac osteotomy is suitable for hip dislocation from 1.5 to 6 years old, whose acetabular angle is below 45° and whose head and socket size are more symmetrical. It is also suitable for hip subluxation from the age of 3 to adolescence. 3.Osteotomy of the iliac bone around the joint capsule is suitable for hip dislocation and subluxation from 1 to 14 years old (i.e. before the age of cartilage closure). 4.Acetabular capsulectomy (acetabular capsulectomy, acetabular capsulectomy) is suitable for cases that are older, have severe dysplasia of the acetabulum, have an acetabular angle >45° and have a small head and acetabulum. 5.Pelvic internal displacement osteotomy For untreated congenital hip dislocation or subluxation with acetabular dysplasia >7 years old, and for children <7 years old with a large femoral head and small acetabulum, and whose head and socket are not symmetrical for Salter's iliac osteotomy. 6.Subtrochanteric rotational (shortening) osteotomy The subtrochanteric rotational osteotomy can correct severe anterior femoral neck deformity. It is suitable for those who are over 4 years old and have an anterior femoral neck tilt angle of 60° or more. For older patients with high dislocation and heavy soft tissue contracture, if the repositioning cannot be achieved without tension after preoperative traction and intraoperative release, femoral shortening should be performed at the same time.