Definition of Developmental dysplasia of the hip:

Developmental dysplasia of the hip (DDH) is a dislocation of the hip joint that is present at birth. The condition is found in babies or young children.

Causes, incidence, and risk factors:

The hip is a ball and socket joint. The ball, called the femoral head, forms the top part of the thigh bone (femur) and the socket (acetabulum) forms in the pelvis.

The hip may be all the way out of the joint or the socket may be a little shallow. One or both hips may be involved.

The cause is unknown, but genetic factors may play a role. Low levels of amniotic fluid in the womb during pregnancy can increase a baby's risk of DDH. Other risk factors include:

• Being the first child
• Being female
• Breech delivery
• Family history of the disorder

DDH occurs in about 1 out of 1,000 births.