Developmental Dysplasia of the Hip (DDH) is a defect in the joint of the hip that can occur before, during or after a baby is born. The hip is a ball-and-socket joint; the rounded section of the thighbone, or femoral head, rests in the cup-like hipbone socket also known as the acetabulum. In some cases of DDH the thighbone moves within the socket, causing an unstable hip. In more serious cases, the femoral head becomes dislocated and moves completely out of the socket. In other cases, the femoral head may not reach the socket.
Because DDH can occur prior to birth, some of the causes can be:
- Decreased amniotic fluid (liquid in the womb), usually in first pregnancies
- Abnormal positioning of the fetus in the womb, such as breech (feet first in the birth canal)
- Infant’s reaction to mother’s hormones that relax the ligaments in preparation for delivery, causing the newborn’s hip to soften and stretch during labor
- Family history of DDH
DDH generally affects just one side of the body, usually the left side. Pain is not common in children diagnosed with DDH. Depending on the severity of DDH, it is sometimes hard to see the symptoms, but your doctor will look for the following markers:
- The inability to move the thigh outward at the hip at birth
- Hearing a “clicking” sound during routine post-natal examinations
- Varying leg lengths
- Differences between the fat folds of the thigh and around the groin and buttocks
- Three months after delivery the newborn may have variance in the hip motion and the affected leg appears shorter
- In older children, the spinal curvature may be more pronounced, which is the body’s overcompensation for the abnormally developed hip
- Older children may develop a limp
Your child’s doctor can determine if they have DDH through the following:
Examination: During routine checkups your child’s doctor can gently push or pull your child’s thighbones to see if they are loose in the sockets, which can indicate DDH. The doctor can also push the femoral head out of the socket; if there is a “clicking” sound it may indicate a dislocation.
X-ray/Ultrasound: Your child’s doctor may want to get an X-ray or ultrasound to get a better view of the dislocation. Ultrasounds are recommended for babies ages 4 months and under since their hip tissue has not hardened and will not be visible on X-ray images.
The treatments offered at Shriners Hospitals for Children® for DDH can vary depending on the age of your child and severity of their condition.
Pavlik Harness: If an unstable hip is diagnosed in a newborn, your child’s doctor may prescribe positioning the hip properly with a Pavlik harness. This harness keeps the femoral head in its socket by holding the affected knee toward your child’s head. A shoulder harness attaches to foot stirrups to keep the leg elevated. This treatment can last from six to 12 weeks, or until ultrasounds confirm that the hip location is normal.
Closed reduction: For infants younger than 18 months, the affected bone can be manually set into place while your child is under anesthesia.
Open reduction: Surgery to realign the hip and place the thighbone back into the hip socket is recommended for children older than 18 months. During this surgery any tight muscles and tissues surrounding the hip joint are loosened, and then tightened once the hip is in the proper position.
Children older than 3 may need surgery on their pelvis to deepen their hip socket or to realign or shorten their thighbone. Following surgery, they are placed in a body cast while they are recovering.