Congenital hip dislocation (CHD), also called developmental dysplasia of the hip, occurs when a child is born with an unstable hip due to abnormal formation of the hip joint during early stages of fetal development. This instability worsens as the child grows. In some cases, the ball-and-socket hip joint may dislocate periodically, with the ball slipping out of the socket with movement. Sometimes, the joint may be completely dislocated. According to a 2006 article published in American Family Physician, one out of every 1,000 infants is born with a dislocated hip. (Storer and Skaggs, 2006)
In many cases, the cause of CHD is unknown. Contributing factors include low levels of amniotic fluid in the womb, breech presentation (when a baby is born with its hips instead of its head first), and family history of the condition. Confinement in the uterus may also cause or contribute to CHD. This is why the condition is more common in first-time pregnancies where the uterus has not been previously stretched.
CHD is more common in girls. However, any infant can be born with the condition. This is why hospital physicians routinely check all newborns for signs of hip dislocation, and pediatricians continue to examine the hips at well-baby checkups throughout the first year of life.
There may be no symptoms of CHD. This is why physicians and nurses routinely test for the condition. If symptoms are present, they may include:
- legs that turn outward or appear to differ in length
- limited range of motion
- folds on legs and buttocks are uneven when legs are extended and examined side by side
- delayed gross motor development (sitting, crawling, and walking)
Screening for CHD is done at birth and throughout the first year of life. The most common screening method is a physical exam. A doctor will gently maneuver your child’s hip and legs while listening for clicking or clunking sounds that may indicate dislocation. This exam consists of two tests: The Ortalani test involves upward force while the hip is abducted (moved away from the body). The Barlow test involves downward force while the hip is adducted (drawn across the body). These tests are only accurate prior to 3 months of age. In older infants and children, exam indicators include difference in leg lengths (only if a single hip is affected), limping, and limited abduction.
Imaging tests are used to confirm a CHD diagnosis. Infants younger than 6 months are generally examined by ultrasound, whule X-rays are used to examine older infants and children.
Infants diagnosed prior to 6 months of age will usually be fitted for a Pavlik harness. This harness presses the hip joints into the sockets. The hip is abducted by securing the legs in the harness in a froglike position. Infants may wear the harness for six to 12 weeks, depending on the age of the child and the severity of the condition. Your child may be instructed to wear the harness full-time or part-time.
If treatment with a Pavlik harness is unsuccessful or the diagnosis is made after your child is too big for the harness, surgery may be required. Surgery is conducted under general anesthesia and may include maneuvering the hip into the socket (closed reduction) or lengthening tendons and removing other obstacles before positioning the hip (open reduction). After the hip is positioned, the hips and legs will be in casts for at least 12 weeks.
If a child is 18 months or older or has not responded well to treatment, femoral or pelvic osteotomies may be required to reconstruct the hip. This means a surgeon will divide or reshape the head of the femur (the ball of the hip joint) or the acetabulum of the pelvis (the socket).
Complicated or invasive treatment is less likely to be necessary when CHD is identified early and can be treated with a Pavlik harness. Between 80 and 95 percent of cases identified early are resolved in this manner, depending on the severity of the condition. (Storer and Skaggs, 2006)
Surgical treatments vary in their success rates, with some cases being resolved after one procedure and others requiring many surgeries and years of monitoring. CHD that is not successfully treated in early childhood can result in early arthritis and severe pain later in life.
If your child has been successfully treated for CHD, he or she will likely continue to regularly visit an orthopedic specialist to make sure the condition does not re-emerge with growth.
CHD can’t be prevented. It is important to regularly bring your child to well-baby checkups so the condition can be identified and treated as soon as possible. You may want to verify that your newborn has been examined for signs of hip dislocation before leaving the hospital following his or her birth.