Developmental Dysplasia of the Hip
What Is It?
In a normal hip joint, the rounded top of the thigh bone (femur) fits into a cup-shaped socket in the pelvis called the acetabulum. This type of joint is called a ball-and-socket joint.
In developmental dysplasia of the hip, the top of the femur moves in and out of the socket either part way or all the way. When it moves all the way out of the socket, it is called a dislocation. This happens when the ligaments that hold the two bones together are very loose or because the cup-shaped socket is not deep enough.