A. A pediatric orthopaedic surgeon can usually make a diagnosis of DDH after examining the child’s hip joints. The diagnosis is confirmed in children smaller than 4 months by using a sonography. In older children, an x-ray is used to confirm the diagnosis.
Q. What is ‘Congenital Dislocation of the Hip’?
A. Congenital Dislocation of the Hip (CDH) means a condition in which a child’s hip joint is dislocated from the time of birth. This is an old term and has now been replaced by the term ‘Developmental Dysplasia of the Hip’ (DDH). This is a broad term that describes any condition in which the hip joint is not developed normally and is unstable.
Q. What exactly happens in DDH?
A. The hip joint is formed by ball like head of the femur that connects with the cup like socket of the pelvic bone. The ball and socket normally fit very closely together and the joint remains stable. In DDH, the hip joint is unstable, that is, the ball is loose in the socket. This instability may be of varying severity.
Q. What causes DDH?
A. In DDH, the shape of the acetabulum is abnormal. The cup is shallow instead of deep and so the femoral head does not fit tightly into it. The soft tissues around the hip joint may also be loose. One or more of these factors may act simultaneously to cause the hip joint to dislocate.
There are a number of risk factors for DDH i.e. factors that increase the likelihood of a child having DDH. These include:
- Breech position – When the baby is delivered legs first instead of head first
- Family history – When either one of the baby’s parents had suffered from DDH during childhood, their baby is 12 times more likely have DDH.
- Tight swaddling of newborns – It increases the risk of DDH.
DDH is much more common is girls, eight out of every ten cases of DDH is seen in baby girls.
Q. How often does DDH occur?
A. Approximately 1 or 2 babies out of every 1000 babies born suffer from DDH.
Q. They say that swaddling causes DDH. But swaddling is the only way my child falls asleep. What should I do?
A. Swaddling is safe as long as it is done correctly. ‘Hip-safe swaddling’ is where you bundle your baby is such a way as to leave his legs free and able to move. As long as you allow the legs to remain in this position when swaddled, it will not harm the hips.
Q. What are the symptoms of DDH?
A. DDH is painless. Hence it very often goes undiagnosed in infancy unless a child is specifically examined for it. Suspicion of an abnormality is usually raised only when the child starts to walk. The child walks with a limp. One of his/her legs appears to be shorter than the other.
Q. If DDH is painless, why does it need to be treated?
A. DDH is painless during childhood. However, if it remains untreated, as the child grows older, the abnormal walking puts a strain on other parts of the body. Eventually, they develop pain in the back and knees.
Further, treatment for DDH is simpler the earlier it is done. Older children require more complicated surgeries and have poorer results.
Q. How is DDH treated?
A. Treatment of DDH depends on the age at which it is diagnosed.
Up to 6 months:
In infants this small, treatment consists of a brace known as a Pavlik harness. This is a soft brace made of fabric, that is fastened into position with Velcro straps. It acts by gently keeping your baby’s legs in a position that allows the hip to get back into the joint.
If treatment with the Pavlik harness is unsuccessful, your baby may need to be treated as for slightly older children (see below)
6 months to 18 months:
Children seen at this stage are usually treated by something called ‘arthrogram and closed reduction’. This is done under anaesthesia in the operation theatre. If this is successful, a body cast known as ‘hip spica’ is applied. This cast will remain for two months, changed once in between.
Closed reduction means that the joint has been reduced without actually opening it. This is not always possible however, especially in older children. When closed reduction fails, or if your doctor feels it is unlikely to be successful, he/she will advise ‘open reduction’ (see below).
Older than 18 months:
In children older than 18 months, open reduction is usually necessary. This surgery might also include femoral and pelvic osteotomies.
After this surgery also, a hip spica cast is applied, usually for two months.
The above is only an outline to the approach to treatment of a child with DDH. Actual treatment depends on many factors and not just the age of the child.
Q. My child’s treatment is completed. Do I still need to take her to the Orthopaedician for check-ups?
A. Yes, it is important that you keep a regular follow up with your surgeon. As your child grows, the bones around the hip change, and sometimes, some part is not able to keep up. Some instability of the hip may occur again as the child grows. This must be detected soon so that it can be treated. Ideally, you must continue follow up with your doctor, at least once a year, until your child’s growth is complete.