Hip dysplasia (developmental dysplasia of the hip)

Right now, you probably have lots of questions: How serious is developmental dysplasia of the hip? What’s the best treatment? What do we do next? Here at Children’s Hospital Boston, we’ve provided some answers to your questions on this site, and our experts can explain your child’s condition fully when you meet with us.

What is DDH?

The hip is a ball-and-socket joint: The ball (femoral head), is the top part of the thigh bone, and the socket (acetabulum) is part of the pelvis.

Hip dysplasia is a relatively common abnormality of the hip joint, occurring on a spectrum of abnormality in relation to the joint’s stability and/or shape. The severity of DDH ranges from just a minor looseness of the ligament that holds the ball in the socket to a complete dislocation, in which the ball is entirely out of the socket.

In DDH, the hip socket may be too shallow and/or the ligaments too loose—letting the ball of the thigh bone (femoral head) slip in and out of the socket, partially or completely.

The abnormal development in hip dysplasia usually causes the head of the thigh bone (femoral head) to put too much pressure on the rim of the hip socket. Over time, this can damage cartilage and is the leading cause of osteoarthritis (joint inflammation), and its resultant disability, in adults.
 

What are the signs and symptoms of DDH?

Most babies and young children with DDH experience no pain. But because the hip may be partially or completely dislocated—meaning the ball of the femur slips partially or completely out of the hip socket—some common signs can include:

• the leg on the side of the dislocated hip may appear shorter
• the leg on the side of the dislocated hip may turn outward
• the folds in the skin of the thigh or buttocks may appear uneven
• the space between the legs may look wider than normal
   

What causes hip dysplasia?

The cause of hip dysplasia is still being researched, but it’s thought that genetics plays a role.
 

What abnormal developments characterize hip dysplasia?

Typically, hip dysplasia is characterized by:

• ligaments that are too loose
• inadequate development of the hip socket
• a hip socket that’s shallow—"dish-shaped" rather than "cup-shaped"
• a hip socket where the upper portion is tilted outward rather than in the normal horizontal orientation

People with milder cases of hip dysplasia often go through childhood and adolescence without experiencing symptoms or even knowing about their condition. But in young adulthood, they may start having hip pain and need to seek medical care.
 

How common is hip dysplasia?

Hip dysplasia is the most common developmental hip deformity in children—and the most common single cause of osteoarthritis of the hip in young and older adults. The condition affects one or two out of 1,000 babies.
 

Who’s at risk for developing hip dysplasia?

The risk for hip dysplasia and hip instability increases with any situation that stretches the baby’s hip ligaments (an issue of stability) or causes her legs and hips to be positioned so that the ball of the thigh bone slips out of the hip socket (an issue of shape). The risk is higher for:

• children in families where there’s a genetic predisposition for the condition
• females, who have looser ligaments than males
• first-born babies, whose fit in the uterus is tighter than in later babies
• breech babies, whose constrained position tends to strain the joint’s ligaments
   

My child’s DDH is mild. Does she still need treatment?

If a child who has hip dysplasia remains relatively pain-free, parents may sometimes be tempted to leave their child’s diagnosed condition untreated. But even if a child who has DDH grows to adolescence without developing pain or a limp, it’s inevitable that her untreated dysplastic hip will wear out and become arthritic in adulthood. Parents need to understand that sometimes DDH treatment in childhood is prophylactic (preventive)—to prevent serious hip disease and possible disability later on.
 

How is developmental dysplasia of the hip diagnosed?

Hip dysplasia can sometimes be detected at birth, and can almost always be diagnosed with ultrasound screening. But ultrasounds for DDH in newborns are performed only selectively—most likely if the baby’s sibling or relative has the condition. At birth, the pediatrician or newborn specialist (neonatologist) does use gentle manipulations to screen a newborn for hip dysplasia, but often the condition isn’t detectable until later.

Since newborns in the United States can go undiagnosed for DDH, the condition is more often detected by evaluations in infancy. A child’s pediatrician can often detect DDH in a clinical exam, during which the doctor looks for instability in the hip joint. At the exam, the doctor also takes the child’s complete prenatal and birth history, including asking whether other family members are known to have DDH.

Diagnostic testing may include:

• ultrasound (sonography): The preferred diagnostic tool in babies under 6 months of age, ultrasound can detect a dysplastic hip (incorrect development of the socket) or a dislocated hip (the femur is out of the socket).

• x-ray: If a child is 6 months of age or older, x-rays are needed to diagnose DDH. An x-ray uses invisible electromagnetic energy beams to produce images of bones, internal tissues and organs onto film.

For details on diagnosing DDH, see Tests.
 

How does Children’s treat developmental dysplasia of the hip (DDH)?
For mild cases of DDH, the baby’s hip often just needs to be closely monitored by the doctor, since the condition frequently corrects itself. For more severe cases, treatment options for infants may include:

• Pavlik harness: A Pavlik harness is used on babies up to 4 months of age to hold the hip in place, while allowing the legs some movement. The harness is usually worn full-time for at least six weeks, then part-time for about six more weeks.
   
• traction or casting: If the hip continues to be partially or completely dislocated, traction or casting may be needed. Traction is the application of a force to stretch certain parts of the body in a specific direction. Traction consists of pulleys, strings, weights and a metal frame attached over or on the bed.
   
• surgery and casting: If the other methods aren’t successful, or if DDH is diagnosed after your child is 2, she may need surgery to put the hip back into place manually (known as a "closed reduction"). After surgery, a spica cast (a cast that extends from the nipple line to the legs) is put on the baby to hold the hip in place, and is worn for about three to six months.

For details on treatments for DDH for all age groups, see Treatment & care.
 

Is there a danger of pain or early arthritis when my child grows up?

In a very young child who develops DDH, there’s usually little or no pain, but pain may develop as the child begins to walk. If untreated or undertreated in childhood, DDH is the most common cause of early arthritis (and its attendant disability) in young adults. Untreated, the condition can also cause pain, a limp and/or differences in leg length.
 

Will my child be OK?

The vast majority of children treated for DDH at Children’s have corrections that enable their bones to grow normally—so they can walk, play, grow and live active lives. Diagnosing and treating your child’s DDH in infancy greatly increases the likelihood of a successful outcome.

The clinical research and basic science leaders at Children’s Orthopedic Center are recognized throughout the world for their achievements in the field. Our breakthroughs mean that we can provide your child with the most innovative care available.
 

What new research is Children’s doing regarding developmental hip conditions?

Developmental hip conditions such as hip dysplasia, Legg-Calve-Perthes disease and slipped capital femoral epiphysis can lead to premature arthritis in young adults with resultant pain and disability.

Our many research studies focus on understanding the mechanical forces (pathomechanics) that adversely change the hip’s structure and function. With better understanding, we can improve existing therapies and develop new therapies for these conditions.

For more on Children’s extensive orthopedic research, see Research & innovation.
 

FAQ
 

Q: What is DDH?

A: Developmental dysplasia of the hip is a condition in which the hip joint doesn’t develop normally. The hip socket may be too shallow and/or the ligaments too loose—allowing the ball of the long leg bone (femoral head) slip in and out of the hip socket, partially or completely.
 

Q: If my child has DDH, will he be OK?

A: The vast majority of children treated for DDH at Children’s have corrections that enable their bones to grow normally—so they can walk, play, grow and live active lives. Diagnosing and treating your child’s DDH in infancy greatly increases the likelihood of a successful outcome.
 

Q: How does Children’s treat DDH?

A: The goal of treatment is to put the femoral head back into the socket of the hip so the hip can develop normally. Treatment options vary for infants and may include:

• Pavlik harness: A Pavlik harness is used on babies up to 4 months of age to hold the hip in place, while allowing the legs to move a little. The harness is usually worn full-time for at least six weeks, then part-time for another six weeks.
   
• traction or casting: If the hip continues to be partially or completely dislocated, traction or casting may be needed. Traction is the application of a force to stretch certain parts of the body in a specific direction. Traction is usually used for about 10 to 14 days.
   
• surgery and casting: If the other methods aren’t successful, or if DDH is diagnosed after your child is 2, she may need surgery to put the hip back into place manually. After surgery, the baby wears a spica cast (extending from the nipple line to the legs) to hold the hip in place for about three to six months.
   

Q: What are the signs and symptoms of DDH?

A: Most babies and young children with DDH are pain-free (asymptomatic). Common signs can include:

• the leg on the side of the dislocated hip may appear shorter
• the leg on the side of the dislocated hip may turn outward
• the folds in the skin of the thigh or buttocks may appear uneven
• the space between the child’s legs may look wider than normal
   

Q: If my child has DDH, what should I ask my Children’s doctor?

A: Some of the questions you may want to ask include:

• Could you describe what’s wrong with my child’s hip joint?
• Are other tests needed to confirm this diagnosis?
• Is there, or could there be, damage to her tissues or blood vessels?
• What treatment options are there?
• Will DDH affect her growth plate, and the normal growth of her leg?
• How long will it take for her to heal?
• Will she need to wear a harness or cast?
• Will she need rehab or physical therapy?
• Will there be restrictions on my child’s activities? If so, for how long?
• Could there be long-term effects? Pain? Arthritis?
• What can we do at home?
   

Q: How is DDH usually diagnosed?

A: Diagnostic testing may include:

• physical exam: At birth, the doctor uses gentle manipulations to screen for instability in the hip joint of the newborn. But even if your baby has DDH, this screening is often negative. It’s more likely that your child’s pediatrician will detect DDH a few weeks or months later during a physical exam.

• ultrasound (sonography): Ultrasound is the preferred diagnostic tool in babies under 6 months of age. But ultrasounds at birth for DDH are done only selectively—most likely if the baby’s sibling or relative has the condition.

• x-ray: If a child is 6 months of age or older, x-rays are needed to diagnose DDH.
   

Q: What’s the long-term outlook for a child who has DDH?

A: Treating your child’s DDH in infancy greatly increases the likelihood of a successful outcome. The vast majority of children treated for DDH at Children’s have treatments that enable their bones to grow normally—so they can walk, play, grow and live active lives.
 

Q: What are the causes and risk factors for DDH?

A: In hip dysplasia, the socket is too shallow and/or the ligaments too loose—allowing the ball of the thigh bone slip in and out of the socket, partially or completely. Researchers are looking for a definitive cause, but it’s thought that genetics plays a role.

The risk for hip dysplasia and hip instability increases with any situation that stretches the baby’s hip ligaments or causes her legs and hips to be positioned so that the ball of the thigh bone slips out of the hip socket, as can happen with:

• children in families where there’s a genetic predisposition for the condition
• females, who have looser ligaments than males
• first-born babies, whose fit in the uterus is tighter than in later babies
• breech babies, whose constrained position tends to strain the joint’s ligaments
   

Q: What is Children’s experience treating hip problems in children and teens?

A: At Children’s, we’re known for our clinical innovations, breakthrough research and leadership in treatment for DDH and other hip problems. We offer the most advanced diagnostics and treatments—several of which were pioneered and developed by Children’s researchers and clinicians.

Many adolescents and young adults with hip problems need diagnostic and surgical techniques that differ significantly from what’s indicated for younger children. Children’s Child and Adult Hip Preservation Program is the only such program in the world. We offer the extensive experience and advanced techniques of clinicians and researchers dedicated to finding better ways to care for adolescents and young adults with hip problems.

Causes
 

In hip dysplasia, the socket is too shallow and/or the ligaments too loose—allowing the ball of the thigh bone slip partially or completely in and out of the hip socket. Why this can happen hasn’t been confirmed, but it’s thought that the condition is influenced by:

• genetics
• the position and constraints of the fetus in utero
• first-born birth order
• gender (female)

Signs and symptoms
 

Common signs of DDH include:

• the leg on the side of the dislocated hip may appear shorter
• the leg on the side of the dislocated hip may turn outward
• the folds in the skin of the thigh or buttocks may appear uneven
• the space between the legs may look wider than normal

Tips if your child needs a cast or harness
 

• Keep your child’s cast clean and dry.
• Check for cracks or breaks in the cast.
• Put pads on rough edges to protect the skin from scratches.
• Don’t scratch the skin under the cast by inserting objects inside the cast.
• Use a hairdryer placed on a cool setting to blow air under the cast and cool down the hot, itchy skin. Never blow warm or hot air into the cast.
• Cover the cast while your child is eating to prevent food spills and crumbs from entering the cast.
• Prevent small toys or objects from being put inside the cast.
• Elevate the cast above the level of the heart to decrease swelling.
• Encourage your child to move her toes to promote circulation.
• Don’t use the abduction straps on a Pavlik harness to lift or carry your child.

When to seek medical advice
 

For a diagnosis. Because most babies who have DDH aren’t in pain, a child’s doctor is usually the person who detects DDH. But you may notice if your baby’s:

• leg on the side of the dislocated hip appears shorter
• leg on the side of the dislocated hip turns outward
• skin folds in the thigh or buttocks appear uneven
• space between the legs looks wider than normal

If your child is wearing a Pavlik harness or a cast to treat DDH, contact her doctor if she develops:

• fever higher than 101 degrees F.
• increased pain
• increased swelling above or below the cast
• numbness or tingling sensation
• drainage or foul odor from the cast
• cool or cold fingers or toes
  
   

Questions to ask your doctor
 

If your baby or child is diagnosed with DDH, you may feel a bit overwhelmed. It can be easy to lose track of the questions that occur to you. Lots of parents find it helpful to jot down questions as they arise; that way, when you talk to your child’s doctors, you can be sure that all your concerns get addressed.

Some of the questions you may want to ask include:

• Could you describe what’s wrong with my child’s hip joint?
• Are other tests needed to confirm this diagnosis?
• Is there, or could there be, damage to her tissues or blood vessels?
• What treatment options are there?
• Will DDH affect her growth plate, and the normal growth of her leg?
• How long will it take for her to heal?
• Will she need to wear a harness or cast?
• Will she need rehab or physical therapy?
• Will there be restrictions on my child’s activities? If so, for how long?
• Could there be long-term effects? Pain? Arthritis?
• What can we do at home?

Who’s at risk
 

The greatest incidence of DDH occurs in:

• children in families where there’s a genetic predisposition for the condition          
• females, who have looser ligaments than males
• first-born babies, whose fit in the uterus is tighter than in later babies
• breech babies, whose constrained position tends to strain the joint’s ligaments

Complications
 

The great majority of non-surgical and surgical treatments of DDH at Children’s occur without complications. But if left untreated, the condition will eventually become painful, and a limp and/or differences in leg length may develop.

The maldevelopment in hip dysplasia usually causes the head of the thigh bone (femoral head) to put too much pressure on the rim of the hip socket. Over time, this can damage cartilage and is the most common cause of premature arthritis (and its attendant disability) in young adults.

Long-term outlook
 

Children’s research into bone problems means that we can provide your child with the most innovative care available. As a result, the great majority of children treated for DDH at Children’s have corrections that enable their bones to grow normally—so they can walk, play, grow and live active lives.

For teens
 

If you’re a teen with a developmental hip problem, you have a lot to cope with. Besides the typical issues any teenager faces—from social acceptance to body changes and more—you may also be dealing with pain; medical appointments and procedures; keeping your cast safe, clean and dry; and limiting some of your activities for a period of time.

If you’re usually an active person, to be experiencing pain or sitting on the sidelines for a while can be depressing or frustrating. If you feel down, angry or anxious through this important time in your life, speak to your doctor, parent or counselor to get help—they’re all on your team. And remember that Children’s Child and Adult Hip Preservation Program is always here for you, too.

Hip dysplasia glossary
 

• acetabulum: hip socket; a part of the pelvis

• arthritis (osteoarthritis): joint inflammation, resulting in pain, swelling, stiffness and limited movement. Hip dysplasia—which wears away the joint’s cushioning cartilage and contributes to inflammation—is the most common cause of arthritis in adults.

• Bernese periacetabular osteotomy: Children’s standard treatment for a hip socket that’s too shallow in a patient whose socket has finished growing—typically at ages 13 or 14 through adult—and whose hip is still viable enough to be repaired rather than replaced. It’s the most complex and powerful procedure for repositioning the hip socket.
  
  The Center for Families at Children’s: dedicated to helping families find the information, services and resources they need to understand their child’s medical condition and take part in their care

• cartilage: smooth, rubbery tissue that cushions the bones of a joint and other areas; allows the bones to move easily without pain

• cast/harness/brace: external devices used to hold a bones of the hip joint in place while they develop in proper position

• closed reduction procedure/surgery: a procedure in which the doctor repositions the hip bone into the socket from outside the patient’s body, and holds it in place with a harness or cast.
   
• developmental dysplasia of the hip (DDH, hip dysplasia): a spectrum of hip abnormality—ranging from a minor laxity of the ligament that holds the ball in the socket to a complete dislocation, in which the ball is entirely out of the socket.
   
• diagnosis, diagnostics: identifying disease or injury through examination, testing and observation

• femoral head: round-headed top of the thigh bone (femur)

• femur: the thigh bone, the longest and strongest of your child’s bones. The rounded top of the femur (femoral head) joins the hip socket (acetabulum) to form the hip joint.

• ligament: sheet or band of fibrous connective tissue that connects bones or cartilages, either at a joint or in support of an organ

• maldevelopment (dysplasticity): condition in which a bone or joint is not properly developed/developing

• open reduction surgery: a procedure in which the doctor repositions the hip bone into the socket through an incision into the patient’s body

• orthopedic surgeon, orthopedist: a doctor who specializes in surgical and non-surgical treatment of the skeletal system, spine and associated muscles, joints and ligaments

• orthopedics: the medical specialty concerned with diagnosing, treating, rehabilitating and preventing disorders and injuries to the spine, skeletal system and associated muscles, joints and ligaments

• pathomechanics: the mechanical forces of a disease that adversely change the body's structure and function

• Pavlik harness: a harness used on babies up to 4 months of age to hold a dysplastic hip in place, allowing the bones of the hip joint to develop in their correct positions. Hip dysplasia in infants is usually treated successfully with the Pavlik harness.
   
• physical therapy: a rehabilitative health specialty that uses therapeutic exercises and equipment to help patients improve or regain muscle strength, mobility and other physical capabilities
   
• traction: a sustained mechanical pull to a limb to correct a dislocation or broken bone

• ultrasound: a non-invasive diagnostic imaging tool that is the preferred way to diagnose hip dysplasia in babies up to 6 months of age
   
• x-ray (radiograph): diagnostic radiology that shows the dense structures, including bones, inside your child’s body. For children older than 6 months, and for adolescents and adults, x-rays are the most reliable test for diagnosing hip dysplasia.