DEVELOPMENTAL DISLOCATION (DYSPLASIA) OF THE HIP (DDH)
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 babies and children with developmental dysplasia (dislocation) of the hip (DDH), the hip joint has not formed normally. The ball is loose in the socket and may be easy to dislocate.
Although DDH is most often present at birth, it may also develop during a child’s first year of life. Recent research shows that babies whose legs are swaddled tightly with the hips and knees straight are at a notably higher risk for developing DDH after birth. As swaddling becomes increasingly popular, it is important for parents to learn how to swaddle their infants safely and to understand that when done improperly, swaddling may lead to problems like DDH.
In all cases of DDH, the socket (acetabulum) is shallow, meaning that the ball of the thighbone (femur) cannot firmly fit into the socket. Sometimes, the ligaments that help to hold the joint in place are stretched. The degree of hip looseness, or instability, varies among children with DDH.
- Dislocated: In the most severe cases of DDH, the head of the femur is completely out of the socket.
- Dislocatable: In these cases, the head of the femur lies within the acetabulum, but can easily be pushed out of the socket during a physical examination.
- Subluxatable:ild cases of DDH, the head of the femur is simply loose in the socket. During a physical examination, the bone can be moved within the socket, but it will not dislocate.
The majority of the times if DDH is detected at an earlier stage it can be successfully treated without any surgical intervention. A special brace called Pavlik harness is recommended which maintains the hip in a certain position and the eventually the joint remains relocated and becomes stable.
• 6 months to 2 years. If a closed reduction procedure is not successful in putting the thighbone in a proper position, open surgery is necessary. In this procedure, an incision is made at the baby’s hip that allows the surgeon to clearly see the bones and soft tissues.
In some cases, the thighbone will be shortened in order to properly fit the bone into the socket. X-rays are taken during the operation to confirm that the bones are in position. Afterward, the child is placed in a spica cast to maintain the proper hip position.
• Older than 2 years. In some children, the looseness worsens as the child grows and becomes more active. Open surgery is typically necessary to realign the hip. A spica cast is usually applied to maintain the hip in the socket.