Developmental dysplasia of the hip

Developmental dysplasia of the hip (DDH) is a condition where the hip joint does not develop normally. The ball at the top of the thigh bone is loose or slips out of the hip socket, and without early treatment it can affect walking and cause long-term hip problems. This article explains what DDH is, how it is detected, what treatment looks like, and how parents can support healthy hip development.

What Is Developmental Dysplasia of the Hip?

DDH is an umbrella term for a range of hip problems in infants and young children. The hip may be shallow, dislocatable, partially out of joint, or fully dislocated. It can be present at birth or develop during the first months of life.

  • The hip socket (acetabulum) may be too shallow to firmly hold the rounded top of the thigh bone (femoral head).
  • The ligament around the hip can be overly loose, allowing the joint to stretch more than normal.
  • The hip may slip out of the socket completely, which doctors call a dislocation.
  • Sometimes the hip only slips out when a certain movement is performed, which is called a dislocatable or unstable hip.

Parents often ask why one baby gets DDH and another does not. There is no single cause. Instead, a mix of genetics, fetal positioning, and hormones during pregnancy can make the hip joint unstable. For example, a baby in the breech position has less room to move, and that can put extra pressure on the developing hips.

Why Early Detection Matters

The first months of life are the best window for treating DDH because the baby’s hip bones are still soft and growing. If the hip is placed back into the socket early, the socket can reshape around the ball and become stable. Detecting DDH late makes treatment harder and may require surgery.

“A hip that is stable and well-positioned in infancy is more likely to grow into a healthy joint for life.”

  • Early treatment is usually simpler, less painful, and more effective.
  • Late-diagnosed DDH can lead to a limp, leg length difference, or painful arthritis in early adulthood.
  • Newborn screening helps catch DDH before the child starts walking, when complications become more obvious.
  • Repeated exams matter because hips can become unstable after the newborn period.

A practical example: a baby born with a mild click in the hip may have a normal ultrasound one month later, but a follow-up exam at two months may reveal instability. This is why routine checks are scheduled over several visits.

Common Risk Factors

DDH can happen in any baby, but some babies have a higher chance of being affected. Knowing the risk factors helps parents and doctors stay alert.

  • Breech delivery: Babies born feet-first are more likely to have hip instability, especially if the breech position was fixed for a long time.
  • Family history: A parent or sibling with DDH increases the chance that a newborn will also have it.
  • First pregnancy: A tight uterus or less room for movement can affect hip development.
  • Female sex: DDH is more common in girls, likely because of pregnancy-related hormones that loosen ligaments.
  • Postnatal positioning: Swaddling with the legs straight and pressed together can increase the risk of hip problems.

If your baby has one or more of these risk factors, the healthcare team may recommend an ultrasound even if the physical exam looks normal. This is a preventive step, not a diagnosis.

How Doctors Screen for DDH

Screening starts right after birth and continues at well-child visits. The doctor uses physical exam maneuvers and, if needed, imaging tests to see whether the hip is stable.

Physical Examination

  • The doctor gently bends the baby’s knees and moves the hips to feel for a “clunk” or slipping sensation.
  • The Barlow test tries to gently move the hip out of the socket to check for instability.
  • The Ortolani test tries to gently guide a dislocated hip back into place.
  • A hip that is already dislocated may also show less leg movement or a leg length difference.

Physical exams are useful but not perfect. A hip can feel normal in the first days of life and still become unstable later. That is why parents should also watch for asymmetry in leg folds or a delay in crawling and walking, although these signs are not always reliable.

Imaging

  • Ultrasound is the best test for babies under four to six months because the hip is still mostly cartilage.
  • Ultrasound can measure the depth of the socket and show the position of the femoral head during movement.
  • X-rays become more helpful after four to six months, when the bone starts to harden and the hip socket is visible.
Test Typical Timing What It Helps Detect
Newborn physical exam First 24 to 72 hours Instability, dislocation, or limited hip movement
Ultrasound Before 4 to 6 months Socket shape, hip position, and joint stability
X-ray After 4 to 6 months Bony socket maturity and long-term alignment

Treatment Options by Age

Treatment depends on the child’s age, the severity of the condition, and how stable the hip is. The goal is to keep the ball deep inside the socket so the joint can grow properly.

Birth to Six Months

  • A Pavlik harness is the most common treatment in this age group.
  • The harness holds the baby’s hips bent and spread apart in a safe, stable position.
  • Wearing the harness full-time for several weeks can often correct the hip without surgery.
  • Parents remove the harness only for bathing and certain skin checks unless told otherwise.

“A Pavlik harness works best when the hip is flexible and the child is under six months old.”

For example, a two-month-old with a shallow socket may need the harness for six to twelve weeks. The doctor checks the hip with ultrasound every few weeks to see whether the socket is deepening. If the harness does not improve the hip, the baby may need a special cast called a spica cast.

Six Months to Around Two Years

  • If DDH is found later, the hip may need to be gently moved back into place under anesthesia.
  • This is called closed reduction, and it is often followed by a spica cast.
  • A spica cast surrounds the hips and one or both legs to hold the joint still while it heals.
  • The child usually wears the cast for several months, with changes as the hip improves.

In this age group, the bones are more developed but still able to remodel. Closed reduction avoids cutting open the joint, but it may not work if the hip has been dislocated for a long time. In that case, surgery may be needed.

Older Children and Surgery

  • Open reduction surgery is used when the hip cannot be positioned safely from the outside.
  • The surgeon makes an incision, removes tissue that blocks the hip, then places the ball back into the socket.
  • A pelvic or femoral osteotomy may be done to reshape the bones and deepen the socket.
  • After surgery, the child wears a spica cast and then gradually returns to normal activities.

Surgery is more involved and has a longer recovery, but it can still give good long-term results. The key is to treat DDH before the hip joint develops permanent damage.

Everyday Care and Positioning

Even before a diagnosis, parents can practice hip-healthy positioning. The goal is to let the baby’s legs rest naturally, with the knees bent and the thighs spread apart.

  • Swaddle with the baby’s legs free or with enough room for the knees to bend outwards.
  • Hold the baby in a spread-squat position, not with the legs dangling straight down.
  • When using a carrier or sling, choose an option that supports the thighs and keeps the hips in a natural “M” shape.
  • Avoid tight sleepers, baby straight jackets, or any device that forces the legs together.
  • For a child in a Pavlik harness or spica cast, follow the doctor’s instructions for positioning during feeding, sleeping, and car travel.

A simple example: when you place a baby in a car seat, allow the legs to bend outwards instead of pressing them together. This small habit supports healthy hip joint development and is safe for the baby.

Long-Term Outlook

Most babies treated for DDH go on to walk, run, and play normally. The risk of long-term problems depends on how early the hip is stabilized and whether both hips are affected.

  • Babies diagnosed in the first few months often need only a harness and then regular monitoring.
  • Children treated with a spica cast or surgery may need periodic X-rays until they finish growing.
  • Some adults with treated DDH have a higher chance of hip arthritis, especially if the socket was not perfectly shaped.
  • Follow-up appointments are important even when the child feels well because subtle joint changes can be caught early.

Parents often worry about the future, but most children with DDH do very well. The longer the condition goes untreated, the more complex the outlook becomes. That is why routine screening and early response make such a difference.

Frequently Asked Questions

What is developmental dysplasia of the hip?

Developmental dysplasia of the hip is a problem with how the hip joint forms. The ball at the top of the thigh bone does not fit firmly into the hip socket, which can lead to looseness, partial dislocation, or complete dislocation.

Is developmental dysplasia of the hip painful for babies?

In infants, DDH usually does not cause obvious pain. The discomfort becomes more noticeable when a child is older and has a persistent limp or joint stiffness.

Can developmental dysplasia of the hip fix itself without treatment?

Some mild instability resolves on its own in the first weeks of life. However, established DDH that is still present after the newborn period usually needs treatment. Waiting too long can make the condition harder to correct.

At what age is developmental dysplasia of the hip diagnosed?

DDH can be diagnosed at birth, during routine infant checkups, or later if the child develops a limp. In many countries, screening begins in the newborn nursery and continues through early childhood.

How long does a baby wear a Pavlik harness for DDH?

A Pavlik harness is often worn full-time for six to twelve weeks. The doctor uses ultrasound to monitor progress and may adjust the schedule based on how quickly the hip stabilizes.

What happens if DDH is not treated?

Untreated DDH can lead to a noticeable limp, limited hip movement, leg length difference, and early hip arthritis. In severe cases, the hip may remain dislocated into adulthood.

Are there exercises parents can do for a baby with DDH?

Parents should not perform corrective hip exercises unless a doctor or physiotherapist recommends them. The right treatment is positioning or bracing, not pulling on the baby’s legs.

Can DDH affect both hips?

Yes, developmental dysplasia can affect one hip or both hips. When both hips are involved, the signs can be less obvious because both legs look similar, so imaging tests are often useful.

Is DDH related to swaddling?

Swaddling is safe when the legs are allowed to bend and spread naturally. Tight swaddling that forces the legs straight and together can increase the risk of DDH or slow down correction.

Do children with DDH need lifelong checkups?

Many children need periodic monitoring until their bones finish growing. Later, they may not need regular visits unless symptoms appear. A child who had DDH should tell their adult doctor about their history so joint health is followed over time.

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