What Is Developmental Dysplasia of the Hip (DDH)?
DDH occurs when the hip is out of joint or isn’t stable in the joint at birth. The hip might be misshapen at the top of the upper leg bone (also known as the femur) or in the hip socket, a part of the pelvis.
The hip is a ball and socket joint. If the ball isn’t in the socket, it’s dislocated and the hip doesn’t develop normally. In this case, the hip typically doesn’t work properly, and it worsens without correction. Because DDH typically is a condition present from birth, you might also hear of it as congenital DDH or congenital hip dislocation.
Types of Hip Dysplasia
- Acetabular dysplasia: The ball remains in the socket, but the socket is too shallow to keep the ball in place.
- Subluxable: The ball is located normally in the socket, but in certain positions (when pushing on the hip), the ball can be pushed partially out of the socket.
- Subluxed: In resting position, the ball is not located normally in the socket. Instead, it rests partway out of the socket.
- Dislocatable: The hip rests in the normal position, but it can be dislocated easily.
- Dislocated: The hip is completely out of the socket when the child is at rest.