Developmental Hip Dysplasia

Developmental dysplasia of the hip is a condition where the hip joint does not form properly in babies and young children, causing the ball of the hip to fit poorly in its socket or even slip out of place completely.

Table of contents

• What is developmental hip dysplasia?
• Causes and risk factors
• Signs and symptoms
• How is it diagnosed?
• Treatment options
• Outlook and prognosis

What is developmental hip dysplasia?

Developmental dysplasia of the hip (DDH) is a health problem that affects how a baby’s hip joint forms. The hip joint is a ball and socket joint, where the round top of the thighbone (the ball) fits snugly into a cup-shaped socket in the pelvis. In babies with DDH, this joint does not develop normally.^[1]

In DDH, the hip socket may be too shallow, meaning it does not fully cover the ball portion of the thighbone. This causes the hip joint to be loose or unstable. The ball part of the joint may be completely or partly out of the socket, or it may slide in and out of place. Sometimes the condition is called congenital dislocation of the hip or hip dysplasia, but developmental is the preferred term because not all cases are present or identified at birth.^[2][3]

DDH can affect one hip or both hips, though it is more common in the left hip. The condition ranges in severity from mild abnormalities where the socket is slightly shallow to complete dislocation where the ball is entirely out of the socket.^[2][9]

• Hip joint
• Femur (thighbone)
• Pelvis
• Acetabulum (hip socket)

Causes and risk factors

The exact cause of developmental hip dysplasia is not fully understood. The condition is believed to be multifactorial, meaning a combination of genetic, environmental, and mechanical factors play a role. DDH tends to run in families, suggesting genetics are important. If a parent had hip dysplasia as a child, their baby has a 12% higher chance of developing it. If a sibling had DDH, the risk increases by 6%.^[2][12]

Environmental influences during pregnancy can also contribute. The condition may develop when a baby’s response to the mother’s hormones causes the hip ligaments to become extra stretchy. A tight uterus that limits fetal movement or restricts space may also affect how the hip develops.^[8][19]

Certain babies have a higher risk of being born with DDH:^[1][2][3]

• Girls: DDH is much more common in girls than boys
• First-born children: The uterus is smaller and provides limited room for the baby to move
• Breech babies: Babies positioned buttocks-down or feet-down instead of head-down during the third trimester of pregnancy, especially at the time of birth, are at higher risk
• Family history: Having a close family member such as a parent or sibling with DDH increases risk
• Low amniotic fluid: This condition during pregnancy can restrict baby’s movement

Research shows that improper swaddling practices after birth may also contribute to hip dysplasia. Babies whose legs are swaddled tightly with the hips and knees straight are at notably higher risk for developing DDH. When swaddling is done properly, with the legs able to bend and spread apart, this risk is reduced.^[2]

Signs and symptoms

Developmental dysplasia of the hip does not usually cause pain in babies and young children, which can make it hard to notice. This is why doctors routinely check the hips of all newborns and babies during well-child visits.^[1][3]

Parents might notice the following signs:^[1][7][24]

• The baby’s hips make a popping or clicking sound that is heard or felt
• The baby’s legs are not the same length, with one appearing shorter
• One hip or leg does not move the same as the other side
• One leg turns outward more than the other
• The skin folds under the buttocks or on the thighs do not line up evenly
• There is limited range of motion on one side, particularly when spreading the legs apart during diaper changes
• The child has a limp or waddle when starting to walk

Babies with any of these signs should see a doctor to have their hips checked. Many babies are born with hips that feel loose when moved around, a condition called neonatal hip laxity. This happens because the ligaments that connect bones are extra stretchy. Hip laxity usually improves on its own by 4 to 6 weeks of age and is not considered true DDH. However, follow-up visits are important because babies whose hip ligaments remain loose after 6 weeks might need treatment.^[1]

How is it diagnosed?

Healthcare providers screen all newborn babies for hip dysplasia in the hospital before they go home. The doctor performs a physical examination, gently moving the baby’s legs into various positions to check if the hip joint fits together properly and to feel for any instability. During well-baby checkups, the hips are checked again at 6 to 8 weeks of age and at subsequent visits.^[2][3]

During the hip examination, the doctor looks for differences in how far each leg can move, uneven skin folds, and differences in leg length. Special maneuvers called the Ortolani test and Barlow maneuver help detect whether the hip can be moved in and out of the socket.^[4]

If the doctor suspects DDH based on the physical exam, or if the baby has risk factors such as breech birth or family history, imaging tests are ordered:^[2][3]

• Ultrasound: This test uses sound waves to create images and is the preferred method for babies younger than 6 months old. It is recommended between 4 and 6 weeks of age for babies at higher risk
• X-rays: These are usually used after about 6 months of age when more of the hip bone has developed and shows up clearly on x-rays

Some babies with DDH are diagnosed right after birth, while others may not show signs until they are older and begin walking. Early diagnosis is important because finding and treating DDH early usually means a better chance for the baby’s hips to develop normally.^[1]

Treatment options

Treatment for developmental hip dysplasia depends on the age of the child and how severe the condition is. The goal is to hold the ball of the hip firmly in the socket so the hip can develop normally. Early treatment helps avoid the need for surgery and leads to better outcomes.^[3][13]

For newborns and young infants (birth to 6 months)

Most babies diagnosed with DDH early in life are treated with a special brace or harness:^[3][11][13]

Pavlik harness: This is the most common treatment for babies younger than 6 months old. The Pavlik harness is made of soft fabric straps that attach to the baby’s shoulders, trunk, and legs. It holds both hips in a stable position with the legs spread apart and bent, which allows the hip joint to develop normally. The harness is worn continuously, usually for 6 to 12 weeks, and should only be removed by a healthcare professional. After the hips become stable, the harness may be worn part-time for another 4 to 6 weeks.

Parents receive detailed instructions on caring for the baby while wearing the harness, including how to change diapers and clothes without removing it, how to clean the harness if soiled, and how to prevent skin irritation. Babies can move their legs freely within the harness.

Other braces: If the Pavlik harness is not effective, other types of fixed abduction braces or a von Rosen splint may be used. These devices work similarly by holding the hips in the correct position.^[16]

For older infants (6 months and older)

If DDH is diagnosed after 6 months of age, or if earlier treatments have not worked, more intensive treatment may be needed:^[3][11]

Spica cast: This is a hard fiberglass cast that covers the child’s body from the chest or waist down to the legs, holding them in the correct position. The cast is usually worn for 12 weeks or longer. During this time, parents learn special techniques for keeping the child clean and comfortable.

Surgery

Surgery may be needed if the baby is diagnosed after 6 months of age, or if braces and casts have not successfully positioned the hip. The most common surgery is called reduction, which involves placing the ball of the thighbone back into the hip socket:^[3][11]

• Closed reduction: The doctor repositions the hip without making large cuts, performed under general anesthesia
• Open reduction: A surgical cut is made in the groin area to allow the surgeon to place the femoral head into the hip socket and remove any tissue blocking proper positioning

After reduction surgery, the child typically wears a cast for at least 12 weeks. The hip is checked again after 6 weeks to ensure it is stable and healing properly. Some children may also require bone surgery called osteotomy to correct the shape of the socket or thighbone, either during the initial surgery or at a later date.^[3]

Outlook and prognosis

Most infants treated for DDH develop into active, healthy children with no hip problems, especially when treatment begins early. With early diagnosis and treatment—particularly before 6 months of age—children are less likely to need surgery and more likely to develop normally.^[1][3]

Without early treatment, DDH can lead to long-term problems including:^[3][9]

• Problems moving around, such as limping
• Pain in the hip and back
• Osteoarthritis (wearing down of the joint surface) at a young age—DDH is a leading cause of hip arthritis before age 60
• Persistent hip dislocation
• Legs of different lengths

The severity of the condition and how late it is discovered increase the risk of arthritis. Therefore, early screening, diagnosis, and treatment are critical to preventing these complications and ensuring the best possible outcome for the child’s hip development and future quality of life.^[4][9]