Developmental Dysplasia of the Hip (DDH)

“Early detection, lifelong mobility — treating Developmental Dysplasia of the Hip from infancy.”

What is DDH?

Developmental dysplasia of the hip, commonly known as DDH, is a problem with the manner in which a baby’s hip joint forms. The hip joint is a ball-and-socket joint. The top part of the thighbone sits inside the socket, which is a part of the pelvic bone. This ball moves around in different directions without going out of the socket. The entire mechanism lets a body move its hips front, back, and side. When the baby develops DDH, the hip doesn’t form properly. The ball part of the joint may be partly or completely out of the socket. In some cases, this ball may slide in and out of the socket. If this problem persists, the hip doesn’t grow well, which may lead to pain while walking and may even cause arthritis at a very young age.

The condition may begin before the baby is born, and in some cases, it may occur after birth during their growth. It may affect one or both of their hips.

What are the Causes of DDH?

The exact cause of DDH in babies is not yet known. According to doctors, there could be many factors, including external as well as environmental factors, causing this condition.

• One of the environmental factors includes the baby’s response to the hormones of the mother during pregnancy.
• A tight uterus that prevents fetal movement or breech position may also be the cause of DDH in children.
• Infant positioning in the first year of life is one environmental factor that may cause DDH.

What are the Signs and Symptoms of DDH?

As DDH doesn’t cause pain in babies, it may be hard to notice. Doctors check the hips during well-child exams to look for the following signs:

• Hips are making a popping or clicking sound, which is heard or felt
• Legs are not the same length
• One hip or leg doesn’t move as the other one does
• Skin folding under the buttocks or on the thighs doesn’t line up
• Limp in the baby’s stride as they begin to walk.

Who Gets DDH?

Any baby may have DDH. That said, there are higher chances of being born with this condition in the following cases:

• Girl babies
• First-born child
• Breech babies
• A baby with a family member having this condition.

How is DDH Diagnosed?

A well-child examination is the first and most common method to diagnose DDH in babies. If the baby has signs of DDH or is at a higher risk of it, the doctor will order a few tests to confirm the diagnosis.

• An ultrasound of the baby’s hips will be carried out to confirm the condition. This scan uses sound waves to make pictures of the baby’s hip joint. It works best for babies under 6 months of age because most of the baby’s joints are still soft cartilage, which doesn’t appear in an X-ray.
• If the baby is above 6 months of age, the doctor may use X-ray as a diagnostic tool for the confirmation of DDH. At this age, the bones are formed properly, giving visibility on the X-ray report.

What are the Treatment Options for DDH?

Once the condition is confirmed, your doctor refers you to a pediatric orthopaedic surgeon specialising in children’s bone conditions. Depending on the severity of the condition, preference of the parents, and other factors, they may choose from the following treatment options:

Bracing

Bracing is a sought-after DDH treatment option for babies younger than 6 months. The brace is like a harness that comes with a shoulder harness attaching to foot stirrups. This device puts the baby’s legs into a position that guides the ball of the hip joint into the socket, avoiding the condition from progressing further.

The surgeon may recommend you use this harness on your baby for 6-12 weeks. While your baby is in the harness, visit the surgeon for a check-up every 1-2 weeks. They will use ultrasound and other examinations. During the same visit, the medical team will check the positioning of the harness and make required adjustments.

Bracing works well to keep the hips in position, and most babies respond well to this option. Once the harness is removed, they may not need any other treatment. In case bracing doesn’t work for your child, the surgeon may opt for other treatment options.

Closed Reduction and Casting

A child may need a closed reduction if bracing hasn’t been successful in keeping the ball of the hip in the socket. It may as well be an option when the parents start the treatment after 6 months of the baby’s age. This procedure involves the following steps.

• Before the procedure, the surgeon administers general anaesthesia to the baby so they sleep through it and do not feel any pain or discomfort.
• They inject contrast dye into the baby’s joint to see the cartilage part of the ball.
• The surgeon moves the baby’s thighbone so that the ball of the joint goes back into place.
• They put a hip spica cast to hold the hip in place. The baby is made to wear this cast for 2-4 months.
• In some cases, they also loosen the tight muscle in the groin.

Open Reduction and Casting

If closed reduction hasn’t been successful in keeping the ball of the hip in the socket, the surgeon will use open reduction and casting to repair the hip. The surgery is performed on babies older than 18 months.

• After administering anaesthesia to the baby, the surgeon makes a small cut through the baby’s skin.
• They move the muscles out of the way to locate the hip joint and put the ball back in place.
• The surgical cut is closed with the help of stitches under the skin, which do not need to be removed.
• A hip spica cast is put to hold the hip in place. The baby is supposed to wear it for the next 6-12 weeks.
• In some cases, the surgeon also performs surgery on the pelvic bone to deepen a shallow hip socket.

Newborn screening for DDH has allowed for early detection of the condition. If identified early, the treatment outcomes may be successful. The older the baby, the more likely it is that the surgeon will use a surgical approach to repair the condition. Continued follow-up even after a successful treatment is important because, as the child grows into an adolescent, the socket needs to be monitored from time to time. It ensures that the hip is developing properly. Occasionally, additional surgeries may be required to deepen the socket and minimise the risk of arthritis as an adult.

For expert paediatric hip care, consult Dr. Ashwani Maichand.