Congenital hip dislocation, also known as developmental hip dislocation or developmental dysplasia of the hip (DDH) and hip dysplasia, is a relatively common congenital malformation in which the femoral head loses its normal relationship with the acetabulum in the joint capsule, so that it cannot develop normally before and after birth. 1, neonatal and infant manifestations (1) joint movement disorders affected limbs are often flexed, poorer than the healthy side, pedaling power is weaker compared to the other side. The hip joint abduction is limited, the infant is lying down with the hip and knee joint flexed, the examiner holds the knee with both hands, the thumb is on the inside of the knee, the remaining four fingers are on the outside of the knee, the normal infant can generally abduct about 80 °, that is, the knee can basically touch the bed surface. (2) Shortening of the affected limb: The lower limb of the side with the lesion will be slightly shorter than that of the healthy side. (3) Changes in the skin pattern and perineum The skin folds on the buttocks and inner thighs are asymmetrical, and the skin pattern on the affected side is deeper and more numerous than on the healthy side. In female infants, the labia majora are asymmetrical and the perineum is widened. 2, the performance of early childhood (1) lameness: lameness is common. When one side is dislocated, lameness is manifested; when bilateral dislocation is manifested, “duck stance” is manifested, the child’s hip protrudes back significantly, and the waist foreshortening increases. (2) In addition to shortening of the affected limb, there is also inversion deformity. Examination: Children with poor hip abduction, lower limb weakness, unequal limbs, asymmetrical hip pattern and limp should be examined in hospital in time. Ultrasound examination can be chosen for younger infants, while older children need to undergo hip radiography. Treatment of this disease: The principle is early diagnosis and timely treatment. Once the diagnosis of congenital hip dislocation is established after birth, treatment should be started immediately and a near normal functioning hip joint can be expected. The older the age at which treatment begins, the worse the outcome.