What Is Dysplasia of the Hip?

The hip is a “ball-and-socket” joint. In a normal hip, the ball at the upper end of the thigh bone (femur) fits firmly into the socket, which is part of the large pelvis bone. In infants and children with developmental dysplasia (dislocation) of the hip (DDH), the hip joint has not formed normally so the ball is loose in the socket and may easily dislocate.