Hip Dysplasia

What is hip dysplasia?

Hip dysplasia, also known as developmental dysplasia of the hip (DDH) and acetabular dysplasia, is a condition where the hip socket doesn’t fully cover the ball of the femur, causing the hip to partially or completely dislocate. This poor fit (or incongruency) can also lead to premature damage to the cartilage, pain, instability and stiffness.

Hip dysplasia can be present at birth or develop throughout childhood and adolescence. Hip dysplasia is a relatively common condition, affecting about 1 in every 1,000 infants born in the US each year, and is more common in girls. The good news is most babies have no long-term complications if their hip dysplasia is treated when they’re younger than 6 months. Sometimes, older children and adults can develop hip dysplasia, with symptoms such as pain or instability occurring later in life.

woman exercising her hips by running outside on a track

Hip dysplasia symptoms

Symptoms of hip dysplasia differ by age. In infants, one leg may appear longer than the other, or a limp may develop once the child starts walking. One hip may also feel less flexible during diaper changes. In teenagers and young adults, hip dysplasia can lead to pain, limping, giving way or clicking. Further development of arthritis or a labral tear can cause groin pain during activity and a feeling of hip instability.

When to see a doctor

All infants are screened for DDH, but parents should discuss symptoms with their baby’s pediatrician at a well-baby checkup.

You should also visit a doctor promptly if symptoms of hip dysplasia cause:

Limited ability to move a joint or bear weight on a leg
Severe hip pain that doesn’t improve after a few days
Visible changes or deformity to the structure of the hip joint
Any new onset of a limp, hip pain, or feelings of instability in a child or adolescent

What causes hip dysplasia?

The exact causes of hip dysplasia aren’t clear. There are genetic factors, environmental factors, and developmental reasons that can increase the risk.

If the ball of the developing femur isn’t positioned firmly into the hip socket, the socket will not completely form around it. Instead, the socket will become too shallow to fully support the femoral head. As the fetus grows larger and more tightly positioned in the uterus before birth, the shallow hip socket can force the femoral head out of position.

Hip dysplasia risk factors

Hip dysplasia tends to run in families, but any baby can be born with the condition, and anyone can develop it. Though hip dysplasia can affect either hip, it is more common to have it bilaterally with differing severity.

Risk factors for hip dysplasia include:

First-born babies
Larger infants: Babies who are larger and more crowded in the uterus may be at higher risk.
Sex: Girls are two to four times more likely to have hip dysplasia than boys.
Birth position: Babies born breech (feet first) are more likely to develop hip dysplasia.
Family history: Having a parent or sibling with hip dysplasia increases the risk of a child developing it.
Swaddling: Improper swaddling that keeps the hips extended and together can increase the risk of hip dysplasia.

Complications of hip dysplasia

People with hip dysplasia, both adults and infants, are at a higher risk of hip dislocation and early joint degeneration. While dislocations usually happen due to serious trauma, hip dysplasia weakens the hip joint, increasing the risk of partial dislocation that develops over time, known as gradual subluxation. It can also cause looser muscles and ligaments around the hip.

Other hip dysplasia complications can include:

Hip labral tears: As you age, hip dysplasia can damage the labrum, the soft cartilage that forms a rim protecting the hip socket.
Osteoarthritis: Concentrated pressure and friction on the hip socket may damage or wear down the cartilage in the hip joint.
Recurring hip pain: The poor fit of your hip joint can lead to pain and instability.

How is hip dysplasia diagnosed?

In addition to a check right after birth, infants are often screened for hip dysplasia at all their well-child visits. For higher-risk infants, an ultrasound is often performed. Diagnosing hip dysplasia in adolescents and adults requires a combination of a physical exam and imaging tests. Tell your doctor when you first noticed the hip pain and if any activity makes it worse.

Hip dysplasia treatment

Several treatments for hip dysplasia can relieve discomfort and protect the hip joint. Early diagnosis and treatment can lead to options that preserve hip function so you can lead an active life. Your doctors will recommend a treatment depending on your age and the extent of your hip damage.

Infants are usually treated for a few months with a soft brace, such as a Pavlik harness, to help keep their joints aligned as they grow. If your child starts treatment when they are younger than 6 months old, this may be all they need to correct hip dysplasia.