Congenital hip dislocation is now internationally known as developmental hip dislocation, or DDH for short, with an incidence of about 1 in 1,000. Why early treatment? It is enough to understand these three points, i.e. congenital hip dislocation pathological changes include two aspects: first, dislocation of the femoral head, which is not in the acetabulum; second, acetabular dysplasia. These two pathological changes are formed in the fetal period. Third, within six months after birth, if the femoral head achieves concentric repositioning into the acetabulum, the acetabulum has a strong ability to self-solvate and most will develop normally soon. In other words, within half a year of age, we only need to reset the femoral head in concentric circles and wait for the acetabulum to self-form, and most of them can return to normal. After the age of half a year, the ability of self-formation starts to decline, so after the concentric circle is reset from half a year to 1.5 years old, there are still some people who have poorly developed acetabulum and need surgery before the age of 4. After the age of 1.5 years, the ability of the acetabulum to self-form further decreases, and most of them cannot self-form to normal, so pelvic osteotomy is needed to correct the acetabular dysplasia. after the age of 4 years, the ability of the acetabulum to self-form basically disappears, and after the age of 6-8 years, the treatment was abandoned in the past, because there are many complications such as femoral head necrosis and joint stiffness after treatment, so it is better not to treat. With the recent development of more complex pelvic osteotomies, some hip dislocations in older children over the age of 8 can also be operated on, enabling the hip joint to gain a service life of 20 to 30 years. Therefore, early treatment of the disease is the key. What age is early treatment? Truly early is within 3 months of birth, when treatment simply involves wearing a Pavlik sling, and most hips are stable within 6 weeks. Most of them are stabilized by 6 weeks and are completely cured by wearing it for a longer period of time. About 10% of these children are unstable after repositioning and require closed-repositioning plaster fixation. About 8% of them have failed to be reset due to congenital factors and need to be reset by incision. From 3 months to 6 months of age, which is the early to middle stage, the treatment is still very effective. The success rate of sling treatment at this stage is about 50%, and half of the children who are unsuccessful in sling treatment will need to be fixed in a closed reduction cast under anesthesia. During the closed reduction, hip arthrography is often performed at the same time to understand whether the hip has been reset and whether the reset is stable, if it cannot be reset, it should be immediately transferred to incisional reset, so as not to miss a good opportunity. The prognosis for this stage of treatment is relatively good, regardless of whether it is a sling, cast or surgery, as long as the femoral head is concentrically reset, because the acetabulum is still strong at this age and can develop into a normal hip joint. Those who come to treatment at the age of 6 months to 18 months belong to the gray stage. At this time, sling treatment is ineffective, and only closed reduction plaster fixation is possible, and high dislocation requires lower limb traction for 1 or 2 weeks before resetting. If the closed reset fails, an incisional reset is also required. Regardless of closed or open repositioning, about 30% to 40% of children have residual acetabular dysplasia and need acetabular reconstruction surgery before the age of 4 years due to the reduced capacity of the acetabulum at this stage. Why 4 years old? Because after the age of 4 years, the acetabulum is basically incapable of shaping. From 18 months to 6 years of age, it is time for major surgical treatment. Why? The first reason is that closed repositioning is very difficult at this time, and most closed repositioning is not possible. The second is that the few that do get in are very likely to lead to femoral head necrosis. The third reason is that the acetabular dysplasia is no longer able to reshape itself back to normal. Therefore, this stage of treatment often requires three major surgical combinations to be completed at the same time in order to obtain a better treatment result. The treatment after the age of 6 is as described above.