Developmental dysplasia of the hip (DDH) is a name given for a range of conditions that affect children’s hips, mostly at birth (congenital), but sometimes develop as a child grows. DDH could be shallow hip sockets that make the joint more prone to (mild DDH) or children born with the leg bones out of the hip sockets (serious DDH).

DDH occurs once in every 1,000 live births, and is mostly seen in girls. The key in successful treatment, to avoid complications like limping or arthritis as the child becomes an adult, is early diagnosis.

Routine Screening 

Soon after the birth of a child, a family medicine physician or pediatrician takes a complete prenatal history and family history, and conducts a routine medical checkup to ascertain the baby’s health status. This examination includes special maneuvers of the hips to identify any dysplasia or other abnormalities. 

As the child continues to grow, a pediatrician will continue to conduct regular checkups, because hip issues cannot always be diagnosed immediately. If a child is diagnosed, a thorough family history may help ascertain why the dysplasia occurred.

Causes of developmental dysplasia of the hip are not completely understood. The condition is considered to be a “multifactorial trait,” meaning there are several factors that may be responsible.

DDH affects more females than males, especially newborns. Babies with a positive family history of DDH are more likely to develop the condition.

Cramped conditions in utero can also cause DDH, especially in first pregnancies when the uterus is tight and the baby has less room. Oligohydramnios, the condition of having too little amniotic fluid (due to birth defects, placental problems, leaking or ruptured membranes, etc.), can also be a factor. Another possible factor is birth position, especially “breech” births, when a baby’s buttocks are faced towards the birth canal.

The cause can also be chemical. The hormones that relax the mother’s ligaments and allow the baby to pass through the birth canal can sometimes cause the baby’s own hip joints to soften and stretch.

Some of the signs of DDH in infants are an inability to completely extend the thigh outward, asymmetrical or uneven folds of fat across the groin, buttocks, or thighs, one leg shorter than the other, and wider than normal space between the limbs. 

Pain is not a good indicator of DDH because in most cases, an infant will not show signs of pain or discomfort during a doctor’s examination of the hip area.

During routine examination of infants from birth to 3 months old, the family medicine physician or pediatrician conducts a physical examination of the hips consisting of gently pushing and pulling the thighbones to determine how loose they are and whether the displacement from the socket is partial or complete. Audible or palpable “clicks” in the hip during movement of the thigh through its range of motion are classic exam findings that indicate DDH. 

Often, imaging tests such as X-rays or  ultrasound are used to confirm the diagnosis of DDH. In some cases, symptoms cannot be detected at birth. Multiple checkups are recommended until the child is at least a year old.

Treatment of DDH depends on the age and overall health of the infant, and the severity of the condition. A mild case can sometimes resolve itself in the first few weeks of life. 

In infants up to 6 months of age, an orthopedic device known as a Pavlik harness is sometimes used to keep the hips in place. This harness is worn full-time for about six to eight weeks, and then reduced to 12 hours per day for another six weeks, or until an X-ray or ultrasound test shows no signs of abnormality. If the Pavlik harness does not resolve the issue, traction (a series of weights and pulleys attached to a metal frame over a bed that apply force to the hip) may be applied for 10 to 14 days, either at home or at the hospital, depending on the circumstances.

Unfortunately, there are some uncommon complications from using the Pavlik harness. Serious conditions known as avascular necrosis (or osteonecrosis, which is when bone tissue dies from lack of blood) of the femoral head and femoral nerve palsies have been reported. Close follow-up with the treating physician can provide early identification of possible complications and minimize their long-term effects. 

In persistent cases in children under age 18 months, the bone is manually put back into place by a method known as “closed reduction.” In children over 18 months, an “open reduction” method is used to realign the bone.  Both of these are surgical procedures, performed under anesthesia. Following successful surgery, a spica cast is put on the child for around three to six months, to hold the hip in place and promote healing. The cast is changed from time to time to accommodate the child’s growth, and ensure that it remains rigid. The cast stays on until the child’s hip placement is determined to be normal. After removal of the cast, a special brace and physical therapy may be required to strengthen the leg muscles.

Parents of children treated for DDH must be vigilant about looking for possible hip-related issues.

If your family has a positive history for DDH or hip issues, be sure to tell your pediatrician. It is important to remember that while DDH cannot be prevented, the majority of cases can be treated successfully, especially if diagnosed early. A majority of children respond to non-surgical treatment. For instance, success rates with the Pavlik harness are estimated to be between 85 to 90 percent, and some studies show that only one baby in 20 will need surgical intervention.