Developmental dysplasia of the hip (DDH) is a condition that affects how the hip joint forms in babies and young children. It ranges from mild looseness of the joint to complete dislocation. Early detection and treatment of DDH improve the chances for healthy hip growth and reduce the risk of long-term problems. When DDH is found and managed early, most children can expect to have good hip function as they grow. About 90% of newborns with mild instability or dysplasia see their hips develop normally without long-term issues. With timely diagnosis and proper care, most children remain active and have healthy hips.

Developmental dysplasia of the hip refers to several issues that prevent the hip joint from forming normally in babies and young children.

To better understand DDH, it is helpful to review the anatomy of the hip joint. The hip is a “ball and socket” joint:

• The ball: The head of the femur (thigh bone), which has a rounded, ball-like shape. It is also called the femoral head.
• The socket: The acetabulum, a cup-shaped part of the pelvis.

In a healthy hip, the spherical femoral head fits deeply and securely within the acetabulum. When the hip moves, the head of the femur rotates within the acetabulum.

In DDH, the head of the femur does not sit deeply and securely within the acetabulum, as it should. This often happens because the hip socket is too shallow or the surrounding ligaments are too loose to hold the femoral head securely. As a result, the hip can become unstable, and the head of the femur may partially or fully slip out of the socket.

DDH ranges from mild instability to severe dislocation. In mild cases, the hip is only a little loose. In moderate cases, the femoral head sits partially out of the acetabulum (known as subluxation) or sits within the acetabulum but can be pushed out during an exam (known as dislocatable). In the most serious cases, the femoral head slips completely out of the acetabulum (known as a dislocation).

DDH can affect one or both hips, but it is more common on the left side. It may be present at birth or develop in early childhood. Some children do not show signs at first. Symptoms may only appear as they grow and begin to walk. The condition was once called “congenital dislocation of the hip,” but the term “developmental dysplasia of the hip” is now preferred because it covers a range of hip problems and can develop after birth.

Developmental dysplasia of the hip occurs when the hip joint forms abnormally before or after birth, and while the precise reason is unclear, multiple factors can impact hip development.

The hip joint forms as the femoral head and acetabulum interact closely during development; if this interaction is disrupted or unstable, the hip may not develop properly, leading to features such as a shallow acetabulum or loose ligaments.

Possible causes and contributing factors for DDH include:

• Genetic factors: These can play a role, as DDH sometimes runs in families.
• Mechanical factors: Conditions such as the position of the baby in the womb or limited space can affect hip development. For example, babies born in the breech position (bottom down) or those with less room in the womb may have a higher chance of DDH.
• After birth: Certain practices such as tight swaddling with the legs straight and together can increase the risk. This position can keep the hips from spreading naturally, which is important for healthy hip growth.

Most cases are thought to result from a mix of genetic, environmental, and mechanical factors.

Risk factors for developmental dysplasia of the hip typically include genetic, mechanical, and environmental factors that can affect how a baby’s hip joint develops. These include:

• Female sex, as girls are more often affected
• A family history of DDH in parents or siblings
• Being the firstborn, which may mean less space in the uterus
• Higher birth weight, which may restrict hip motion
• Being part of a multiple birth (twins, triplets, etc.), which can reduce space for hip development
• Low amniotic fluid, which limits fetal movement
• Baby born after the due date
• Breech positioning in the womb, which puts extra pressure on the hips
• Keeping a baby's legs straight and together during swaddling, which may limit natural hip movement

Because many infants with DDH have no clear risk factors, routine clinical hip examinations are done at newborn and well-baby visits. Imaging tests are used for infants with risk factors or abnormal exams.

Symptoms of developmental dysplasia of the hip typically involve physical signs of hip instability, restricted joint movement, or asymmetry in the legs or skin folds. These include:

• Less movement in one leg compared to the other
• One leg that turns or points outward more than the other leg
• A limp, toe-walking on one side, or a waddling walk as the child learns to walk
• Uneven or extra skin folds on the thighs or buttocks
• A child who walks with an uneven step or favors one side
• Noticeably shorter leg on one side, seen when lying down or walking
• An inward curve of the lower back (known as increased lordosis)
• Trouble moving the hip outward on the affected side

Some children do not show symptoms in infancy. The condition may only be noticed as they begin to walk.

To diagnose developmental dysplasia of the hip, doctors consider the child's medical and family history, conduct a physical examination, and order imaging tests if necessary. Routine hip screening is part of regular checkups for all infants.

Doctors start by asking about the child’s background and any family history of hip problems. They then perform specific physical tests to assess hip stability and movement—feeling for looseness or a distinct sensation in infants under three months, and checking for restricted movement, leg length differences, or uneven skin folds in older babies.

If the exam suggests DDH or if risk factors are present, imaging tests are used to confirm the diagnosis and guide treatment. The main tests include:

• Ultrasound: Uses sound waves to show hip structures and motion and is preferred in infants under about four to six months while bone is largely cartilage; it shows how well the spherical femoral head sits in the cup-shaped acetabulum and whether the hip is developing normally.
• X-ray: X-rays are used in older infants and children, usually after four to six months of age, when the bones are more developed. X-rays can show the position of the hip and the shape of the socket.
• Magnetic resonance imaging (MRI) or computed tomography (CT): These tests are sometimes used after procedures to align the hip and casting to assess the hip’s position.

Doctors may repeat exams and imaging over time to monitor the hip’s development and response to treatment.

Treatment for developmental dysplasia of the hip focuses on properly aligning the hip joint to ensure healthy development and prevent long-term complications. The specific approach depends on the child's age, the severity of the condition, and how the joint responds to initial interventions.

Treatment for DDH includes:

• Monitoring: Mild instability in newborns may resolve on its own, so doctors may check the hips regularly at first.
• Harness or splint: Devices such as the Pavlik harness keep the hips in a healthy position and are most effective if started before six months of age.
• Stiffer braces: If a soft harness is not enough, a more rigid brace may be used.
• Closed reduction and casting: Under anesthesia, clinicians place the ball-shaped femoral head back into the hip socket and keep it there with a spica cast for a period of months, especially when a harness has not worked. A hip spica cast is a hard cast that extends from the chest down to the legs to immobilize the hip.
• Open reduction surgery: If other treatments are not successful or the child is older, a surgical procedure may be needed to align the hip, followed by hip spica casting.
• Bone surgery (osteotomy): In some cases, reshaping the socket or head of the femur can help improve hip function and prevent future joint problems.

Doctors and care teams teach parents how to care for children in harnesses or casts, including diapering, bathing, and watching for skin problems. Regular follow-up visits and imaging are important to check the hip’s progress.

Complications of developmental dysplasia of the hip may arise from the condition itself or as a result of treatment, often involving long-term changes to joint mobility or bone health. These include:

• Avascular necrosis of the femoral head, which can occur if blood supply to the head of the femur is disrupted or reduced
• Skin irritation or sores from devices if not properly fitted or cared for
• The need for more surgeries if the hip does not heal or problems come back
• Temporary nerve weakness (known as femoral nerve palsy) from pressure caused by braces or casts
• Walking changes such as a limp, tiptoeing on one side, or a side-to-side waddling walk from hip or leg changes
• Residual hip dysplasia, hip dysplasia that continues even after treatment
• Persistent hip pain if alignment is not restored
• Differences in leg length (known as limb length discrepancy), even after treatment
• Early onset of osteoarthritis in the hip if DDH is not managed effectively
• Infection after surgery

Experts recommend regular follow-up and monitoring to help find and address complications as early as possible.

Most children with DDH do well if the condition is identified and managed in the early months. If treatment begins in the first few months of life, most children develop healthy hips and can walk and play as they grow.

If DDH is diagnosed later or is more severe, treatment may be more complex, and there is a higher chance of needing surgery. Some children may have mild differences in leg length or hip shape, but these are often mild and usually do not cause major problems. Regular follow-up is important to monitor hip growth and catch any changes early.

Without treatment, DDH can lead to pain, limping, and early arthritis, which may require hip replacement in adulthood. Early diagnosis and proper treatment provide the best chance for a healthy, active life, allowing most children with DDH to achieve normal function and mobility.

“Yale Orthopedic Surgery cares for patients with developmental dysplasia of the hip from newborn age all the way up to early adulthood,” says Yale Medicine pediatric orthopaedic surgeon Marisa Su, MD. “Our approach focuses on surveillance and early intervention with an emphasis on family-centered care. Each treatment plan is tailored to the specific needs of every patient. We know that this diagnosis can be accompanied by a significant emotional burden on parents during a particularly stressful time in their family's journey, and so we treat every family that enters our clinic doors with compassion and consideration while maintaining the highest standard of care to achieve the best clinical outcome for your child."