What Is Hip Dysplasia?

Your hips are important. They support much of your body’s weight and allow you to move your upper legs so you can walk, climb stairs, and even sit. That���s why a problem like hip dysplasia can have a big impact on your life.

Your hip is the biggest ball-and-socket joint in your body. That means the ball of your thigh bone (femoral head) fits into the socket of your pelvis to form your hip joint. If your hips are normal, the ball rotates freely in the socket to let you move.

But if you have dysplasia, your hip socket doesn't completely cover the ball of your thigh bone, causing your hip joint to easily dislocate.

It also wears your hip joint out faster than normal. Imagine a tire that’s out of balance on a car. The tread on that tire will wear out sooner than it would if it were properly aligned.

Most people who have hip dysplasia are born with it. Doctors usually check for it in newborns, and during each well baby visit until they’re 1 year old.

Causes

Hip dysplasia can run in families and it happens more often in girls than boys. It shows up in babies because the hip joint is made of soft cartilage when you’re born. Over time, it hardens into bone.

The ball and socket help mold each other during this time, so if the ball isn’t fitting properly into the socket, the socket may end up too shallow and not form completely over the ball.

There are a few reasons this can happen right before a baby is born:

  • It’s the mother’s first pregnancy.
  • The baby is large. Or there is oligohydramnios, a condition in which there is too little amniotic fluid in the sac that baby has lived in throughout the pregnancy, that limits baby’s movement.
  • The baby is in the breech position -- meaning the rear, not the head, is toward the birth canal.

All of these things can reduce the amount of space in the womb, which can make things crowded for the baby and move the ball out of its proper position.

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Symptoms

The signs and symptoms of hip dysplasia can depend on age. Babies sometimes have one leg that’s longer than the other, and kids might have one hip that’s less flexible than the other or limp when they start walking.

If you’re a teenager or young adult, the first signs you might notice are hip pain or a limp. You might also have “clicking” or “popping” in the joint, but these can all also be symptoms of other hip disorders.

The pain usually comes on when you’re doing physical activities, and it’s typically located in the front of the groin. But you could also have discomfort in the side or back of your hip. It could start out mild and happen occasionally, and over time become more intense and frequent.

When dysplasia is severe, the pain can cause a mild limp. You might also develop a limp if you have weak muscles, a bone deformity, or limited flexibility in the hip joint. If you have a limp for one of those reasons, you probably won’t feel pain.

Diagnosis

Your doctor probably will look for hip dysplasia at your baby’s first appointment. He’ll check for it by gently moving her legs around in different positions to see if the joint fits together. If your baby was in a breech position, or your doctor suspects she may have dysplasia, he will probably do an ultrasound in the first three months after birth to be sure.

For symptoms later in life, your doctor might suggest certain imaging tests. An MRI can give him information about any damage to the cartilage, and an X-ray can show how severe the dysplasia is.

Treatment

How hip dysplasia is treated also depends on your child’s age. Babies diagnosed early can usually wear a soft brace that holds the ball of the joint in the socket for a few months to help mold it into the proper shape. A baby older than 6 months may need a full-body cast or surgical intervention.

Surgery is usually the only treatment for older children and adults. If the dysplasia is mild, it can usually be treated arthroscopically, which means the surgeon makes tiny cuts and uses long-handled tools and tiny cameras to fix the problem.

But if the dysplasia is more severe, the surgeon may have to cut the socket free from the pelvis and reposition it so it matches up better with the ball. This surgery is called periacetabular osteotomy. Hips severely damaged because of dysplasia might need replacement surgery.

WebMD Medical Reference Reviewed by Renee A. Alli, MD on October 26, 2018

Sources

SOURCES:

Brainlab.org: “What Does a Hip Do?”

International Hip Dysplasia Institute: “Adult Hip Dysplasia,” “Adult Signs and Symptoms,” “Adult Diagnosis.”

Biology Online: “Ball-and-socket joint.”

Mayo Clinic: “Hip dysplasia.”

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