The disease has been previously referred to as congenital dislocation of the hip CDH, but is now considered to be developmental dislocation of the hip or developmental dysplasia of the hip (DDH). In 1992, the North American Society for Pediatric Orthopaedic Surgery renamed CDH to DDH. As research continued, the orthopaedic community gradually reached a consensus that, in addition to congenital factors, acquired factors play an important role in the disease, which presents a dynamic developmental abnormality that may get better or worse as the infant grows and develops, and that the dislocation is not truly congenital, and that DDH has both It is not really congenital, DDH is both a deficiency in the development of the acetabulum during the embryonic period and genetic factors, but it is mainly caused by mechanical factors during delivery and improper swaddling methods after birth, and in a sense, it is preventable. Clinical experience tells us that the earlier the disease is treated, the better the results. As the age increases, the success rate and efficacy of hip resetting gradually decreases, the complications of resetting gradually increase, and the residual deformity of the hip joint keeps increasing. If the hip is not treated early and correctly, the secondary changes will make the reset more difficult, and it will develop into degenerative hip osteoarthritis and disability in adulthood. For this disease, early diagnosis is half the battle, while a wrong diagnosis is half the battle.