Developmental Dysplasia of the Hip

The hip is a ball-and-socket joint that can move in multiple directions. The acetabulum of the pelvis forms the socket, while the femoral head (upper end of femur/thigh) creates the ball. Developmental Dysplasia of the Hip (DDH) is noted in 1-2 out of every 1,000 newborns. Usually, the socket is not formed deep enough to hold the ball. In some cases, the ligaments are stretched, which allows for the hip joint to be unstable.

Though babies can be born with DDH, some develop it due to circumstances such as tight swaddling, and as such, parent education is effective in preventing DDH. There are differing severities of DDH, with mild cases involving the subluxation of the joint without the joint dislocating completely. More serious cases have enough instability to allow for dislocation, while the most severe instances are entirely dislocated.

Causes

Developmental Dysplasia of the Hip happens when the hip joint does not form properly, which makes the hip dislocate easily. Most cases are in newborns; however, some can develop DDH from being swaddled too tightly. DDH can be hereditary and is more common in girls, a firstborn, breech births, and cases with low levels of amniotic fluid during pregnancy.

Symptoms

Since babies cannot communicate and are inactive, DDH can be difficult to diagnose based on symptoms. A pediatrician will examine babies for signs of DDH during each check-up until at least after the first year. Some symptoms may include:

Uneven leg lengths
Less flexibility in one leg/hip movement
Toe walking or a strange gait in those who have started walking.

Diagnosing

During regular wellness checks, a pediatrician will test for hip dysplasia. The diagnostic process includes a physical examination in which they monitor for a “clunk” as the hip is moved in different directions. Ultrasound imaging is used in newborns with suspected DDH, while X-rays can be used in older infants and children.

Treatments

If found early, developmental dysplasia of the hip can be corrected with special bracing, and the child will regain normal function. However, if the condition is not noted at birth or develops later, treatment can be trickier and may lead to complications such as early onset of arthritis, chronic hip pain, and uneven leg lengths.

Conservative Treatment Options

Newborns are usually placed in a Pavlik harness for 1-3 months, which keeps the hip joint in place. This harness encourages the ligaments around the hip joint to tighten, allowing for normal hip joint development.
Infants aged 1-6 months are treated with a similar harness or a spica body cast that holds the hip in the correct position. This can be more difficult to care for but has similar developmental results.
Children aged six months to 2 years are treated in a spica body cast.

Surgical Treatment

In older infants and children, when conservative treatment fails, surgery may be required to put the joint back in place and shorten the femur (thighbone) if necessary. Following surgery, a spica body cast is applied to protect the hip joint while it heals and forms correctly.

Recovery

When bracing/casting is used, monitoring the skin for signs of breakdown or infection is important. It is more challenging to keep the skin clean, and it is vital to keep anything from getting under the cast. X-rays will be taken during follow-up visits to monitor for correct hip joint placement.

Complications

All treatment options, whether conservative or surgical, come with risks. Discuss these risks and potential complications with your provider. Common risks with surgery include infection, bleeding, blood clots, and damage to blood vessels or nerves. Children wearing a brace/cast will have a delay in their ability to walk only until the bracing is completed. Harnesses and bracing can cause nerve damage, but this will improve once the device is removed. There have been rare instances of delayed bone growth. Sometimes, additional surgery is needed later in childhood to correct developmental abnormalities in the hip joint.