What is Congenital Hip Dislocation (CHD)?
Hip joint is formed where head of the femur which is the rounded top of the thigh bone fits into a hollow region of pelvis known as acetabulum. It is like a ball and socket joint that allows smooth movement of the hip joint so that we can walk effortlessly. Due to certain conditions during pregnancy, there occurs structural abnormality of the hip joint like ill-formed head of the femur, shape of acetabulum and supporting structures around the hip joint. This causes a problem in the way hip joint develops. As a result of this, the acetabulum and femur are not in normal contact. When there is only some contact, it manifests as a mild abnormality known as subluxation and when there is no contact, it shows as severe deformity known as dislocation. This condition which manifests at the time of the birth is medically known as congenital hip dislocation (CHD) or developmental dysplasia of hip (DDH).
What are the causes of CHD?
Exact cause is not clear but there are certain factors which are known to increase the chances of a baby born with congenital hip dislocation. These factors are listed below:
- Family history of a parent or sibling born with the dislocation
- Females are more predisposed because of the release of estrogen hormone in the female fetus which causes ligaments to enlarge and move bone out of position.
- During pregnancy a small amount of fluid in the womb (a condition called oligohydramnios) decreases the movement of baby in the uterus. This is most common in first-time pregnant women whose uterus had not stretched already.
- Unborn babies who are in breech position (with their head up and feet down in the uterus).
- Presence of other abnormalities like cerebral palsy, spinal cord problems or other muscle and nerve disorders.
What are the symptoms of CHD?
t’s surprising that many a times there are no symptoms for congenital hip dislocation. Such babies do not appear to be born with any pain or distress. However, when doctors check in newborn babies, they look for following symptoms:
- Different length of legs
- Legs that turn outward
- Limited range of motion
- Slow development of gross motor movement
- Unequal skin folds on legs and buttocks
If not diagnosed earlier, then older children develop with congenital hip dislocation (CHD) develop a limp in their walk or walk on toes.
When and how is it diagnosed? Doctors screen the babies for the symptoms of congenital hip dislocation (CHD) four times during the first one and half years of birth.
– Within 24 hours of birth
– At the 6-week check
– Between 6-9 weeks of age
– At walking age
Usually doctors will gently move the child’s hip and legs. He will listen for a click or clunk sound which indicates dislocation. To confirm their diagnosis, imaging tests like ultrasound (for babies less than 6 months of age) and X-rays (for older ones) are suggested.
What is the treatment? Congenital hip dislocation (CHD) is a serious condition and needs immediate treatment. If left untreated, it causes permanent damage to the hip join and other related complications. Therefore, it is advisable to start earlier treatment soon after birth so as to avoid any long-term implications.
Remember the ball-socket hip joint we discussed before. Treatment of developmental dysplasia of the hip involves moving the round head of the thigh bone (femur) properly into the acetabulum. This ensures the hip joint develops normally. Depending on the child’s age, this can be achieved through various surgical and non-surgical methods.
- For children under 6 months of age – Putting a device called Pavlik Harness to hold the hip in the correct position for at least 12 weeks. The harness is adjusted as the child grows.
- For children over 6 months of age – Under the effect of anesthesia, the doctor corrects the hip position and then put a cast or plaster to maintain it that way. This method is called Closed Reduction and Hip Spica. It is also done when the above method fails.
- For older children – Another surgical option called Open Reduction is used to untie the tendons around the hip and remove any hindrance to the free movement of the hip joint.
If none of the above methods are effective, then more complicated surgeries are done to keep the hip in the right position.
Almost 85-90% of the cases of congenital hip dislocation (CHD) are successfully treated. The key lies in early detection. If left untreated for later stages, then it may develop into arthritis of the hip joint causing severe pain and reduced movement. As the age of the child increases, bone become more and more developed, therefore treatment gets complex and success probability decreases. As far as possible, treatment for CHD should begin before the child starts walking.