Congenital hip dysplasia is a condition of abnormal development of the hip, resulting in hip joint instability and potential dislocation of the thigh bone from the socket in the pelvis. This condition has been in the early 2000s been termed developmental hip dysplasia, because it often develops over the first few weeks, months, or years of life.
Congenital hip dysplasia is a disorder in children that is either present at birth or shortly thereafter. During gestation, the infant's hip should be developing with the head of the thigh bone (femur) sitting perfectly centered in its shallow socket (acetabulum). The acetabulum should cover the head of the femur as if it were a ball sitting inside of a cup. In the event of congenital hip dysplasia, the development of the acetabulum in an infant allows the femoral head to ride upward out of the joint socket, especially when the infant begins to walk.
In the United States, approximately 1.5 percent of all infants have congenital hip dysplasia. Though the worldwide incidence of congenital hip dysplasia varies, researchers estimate the global incidence to be approximately 1 percent.
Clinical studies show a familial tendency toward hip dysplasia with a greater chance of this hip abnormality in the first born compared to the second or third child. Infants with siblings who have been diagnosed with congenital hip dysplasia or who have parents with the defect are at an increased risk. Females are affected four to eight times more than males, and in children with congenital hip dysplasia, the left leg in more often affected. This disorder is found in many cultures around the world. However, statistics show that infants in colder climates have a higher incidence. It is speculated that this increase may be due to the practice of swaddling which can place the infant's legs in an extreme straightened or adducted position, forcing the hips closer together. The incidence of congenital hip dysplasia is also higher in infants born by cesarean and in breech position births.
Jeffrey P. Larson RPT, Deborah L. Nurmi MS, Thomson Gale, Gale, Detroit,