Developmental Dysplasia of the Hip

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What is developmental dysplasia of the hip (DDH)?

Developmental dysplasia of the hip is a congenital (present at birth) condition of the hip joint. It occurs once in every 1,000 live births. The hip joint is created as a ball and socket joint. In DDH, the hip socket may be shallow, letting the “ball” of the long leg bone, also known as the femoral head, slip in and out of the socket. The “ball” may move partially or completely out of the hip socket.

The greatest incidence of DDH occurs in first-born females with a history of a close relative with the condition.

What causes developmental dysplasia of the hip (DDH)?

Hip dysplasia is considered a “multifactorial trait.” Multifactorial inheritance means that many factors are involved in causing a birth defect. The factors are usually both genetic and environmental.

Often, one gender (either male or female) is affected more frequently than the other in multifactorial traits. There appears to be a different “threshold of expression,” which means that one gender is more likely to show the problem than the other gender. For example, hip dysplasia is nine times more common in females than males.

One of the environmental influences thought to contribute to hip dysplasia is the baby’s response to the mother’s hormones during pregnancy. A tight uterus that prevents fetal movement or a breech delivery may also cause hip dysplasia. The left hip is involved more frequently than the right due to intrauterine positioning.

What are the risk factors for developmental dysplasia of the hip (DDH)?

First-born babies are at higher risk since the uterus is small and there is limited room for the baby to move; therefore affecting the development of the hip. Other risk factors may include the following:

family history of developmental dysplasia of the hip, or very flexible ligaments
position of the baby in the uterus, especially with breech presentations
associations with other orthopaedic problems that include metatarsus adductus, clubfoot deformity, congenital conditions, and other syndromes

What are the symptoms of developmental dysplasia of the hip (DDH)?

The following are the most common symptoms of DDH. However, each baby may experience symptoms differently. Symptoms may include:

the leg may appear shorter on the side of the dislocated hip
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

A baby with developmental dysplasia of the hip may have a hip that is partially or completely dislocated, meaning the ball of the femur slips partially or completely out of the hip socket. The symptoms of DDH may resemble other medical conditions of the hip. Always consult your baby’s physician for a diagnosis.

How is developmental dysplasia of the hip (DDH) diagnosed?

Developmental dysplasia of the hip is sometimes noted at birth. The paediatrician or newborn specialist screens newborn babies in the hospital for this hip problem before they go home. However, DDH may not be discovered until later evaluations. Your baby’s physician makes the diagnosis of developmental dysplasia of the hip with a clinical examination. During the examination, the physician obtains a complete prenatal and birth history of the baby and asks if other family members are known to have DDH.

Diagnostic procedures may include:

x-ray – a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
ultrasound (Also called sonography.) – a diagnostic imaging technique which uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. Ultrasounds are used to view internal organs as they function, and to assess blood flow through various vessels.
computed tomography scan (Also called a CT or CAT scan.) – a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.
magnetic resonance imaging (MRI) – a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.

Treatment for developmental dysplasia of the hip (DDH):

Specific treatment for DDH will be determined by your baby’s physician based on:

your baby’s gestational age, overall health, and medical history
the extent of the condition
your baby’s tolerance for specific medications, procedures, or therapies
expectations for the course of the condition
your opinion or preference

The goal of treatment is to put the femoral head back into the socket of the hip so that the hip can develop normally.

Treatment options vary for babies and may include:

placement of a Pavlik harness
The Pavlik harness is used on babies up to 6 months of age to hold the hip in place, while allowing the legs to move a little. The harness is put on by your baby’s physician and is usually worn full time for at least six weeks, then part-time (12 hours per day) for six weeks. Your baby is seen frequently during this time so that the harness may be checked for proper fit and to examine the hip. At the end of this treatment, x-rays (or an ultrasound) are used to check hip placement. The hip may be successfully treated with the Pavlik harness, but sometimes, it may continue to be partially or completely dislocated.
traction and casting
If the hip continues to be partially or completely dislocated, traction, casting, or surgery may be required. 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. The purpose of traction is to stretch the soft tissues around the hip and to allow the femoral head to move back into the hip socket. Traction is most often used for approximately 10 to 14 days. Traction can either be set up at home or in the hospital, depending upon your baby’s physician, hospital, and the availability of the resources.
surgery and casting
If the other methods are not successful, or if DDH is diagnosed after the age of 18 months, surgery may be required to put the hip back into place manually, also known as a “closed reduction. If successful, a special cast (called a spica cast) is put on the baby to hold the hip in place. The spica cast is worn for approximately three to six months. The cast is changed from time to time to accommodate the baby’s growth and to ensure the cast’s rigidity, as it may soften with daily wear.

The cast remains on the hip until the hip returns to normal placement. Following casting, a special brace and physical therapy exercises may be necessary to make the muscles around the hip and in the legs stronger.

What is a short leg hip spica cast?

A short leg hip spica cast is applied from the chest to the thighs or knees. This type of cast is used to hold the hip in place after surgery to allow healing.
Click Image to Enlarge

Cast care instructions:

Keep the cast clean and dry.
Check for cracks or breaks in the cast.
Rough edges can be padded to protect the skin from scratches.
Do not 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.
Do not put powders or lotion inside the cast.
Cover the cast during feedings to prevent spills 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.
Do not use the abduction bar on the cast to lift or carry the baby.

When to call your baby’s physician:

Contact your baby’s physician or healthcare provider if your baby develops one or more of the following symptoms:

fever
increased pain
increased swelling above or below the cast
drainage or foul odor from the cast
cool or cold toes

Long-term outlook for a baby with developmental dysplasia of the hip (DDH):

While newborn screening for DDH allows for early detection of this hip condition, starting treatment immediately after birth may be successful. Many babies respond to the Pavlik harness, traction, and/or casting. Additional surgeries may be necessary since the hip dislocation can reoccur as the child grows and develops. If left untreated, the baby may have differences in leg length, and may limp.

What is congenital dislocation of the hip (CDH)?

The hip joint consists of two structures: a cup-shaped socket (acetabulum) in the pelvis and a ball-shaped upper end of the thigh bone (femoral head). Normally, these structures fit snugly together and are held in place by ligaments and muscles. In congenital dislocation of the hip (CDH), the femur comes out of the acetabulum. (See Glossary at end for definitions of technical terms.)
There are two categories of CDH, typical, which occurs at birth, and teratologic, which occurs prenatally. If the dislocation is left untreated, permanent problems such as a limp, a short leg, and a diminished range of movement may result.

What causes CDH?

The most common cause of CDH is looseness (laxity) of the ligaments surrounding the hip. This is likely due to fetal absorption of the maternal hormones that increase pelvic relaxation just before delivery uterine compression, which forces the infant’s hips into a flexed position and limits fetal movement, is also thought to play a role in CDH.

Sometimes the way the newborn child is held or is placed in the crib may contribute to the development of hip instability and subsequent dislocation.

Some facts about CDH

Dislocatable hips are present in 1 of 80 children at birth. This condition usually spontaneously resolves and becomes stable in a few days.
Clinically evident dislocated hips occur in 1 of 800 hips at birth. This condition does not resolve by itself and requires treatment.
CDH is more common in breech deliveries.
60% of children with CDH are first borns.
There seems to be an hereditary tendency toward CDH.
Dislocation is more common in the left hip (67%) than in right (6%). CDH is generally one-sided but may occur in both hips.
The earlier treatment begins, the easier it is to correct the dislocation.
Dislocation of the hip is difficult to diagnose because it doesn’t cause pain stiffness.
Most hips begin to dislocate at birth but a few dislocate later.

Diagnosis of CDH: After the neonatal period

By the time the infant is 6 weeks of age, the Ortolani and Barlow test are no longer effective diagnostic tools because the soft tissues around the hip joint have tightened.

Diagnosis of CDH: Age 6 weeks to one year

As the infant grows the motion of the affected hip will become restricted. That is, abduction will be limited. An x-ray is required to make a diagnosis at this stage.

Diagnosis of CDH: Age 1 year

If the child is not treated before the age of 1 year, he or she will walk with a limp and leg abduction (doing the splits) will be restricted. The affected limb will also be shorter than the other. Although the child may appear disabled, pain is uncommon and limitations on leg function are slight. Once again, an x-ray is required to make the diagnosis.

Diagnosis of CDH: Adult

The untreated adult will walk with a limp, have legs of unequal length, will a limp, have legs unequal length, will experience fatigue when walking, and may feel pain. Again, an x-ray is useful for diagnosis.

Where can advice be obtained?

If your physician detects hip instability in your infant that does not resolve itself with in 5 days od detection, a referral should be made to an orthopaedic surgeon. The surgeon will check the findings, have an ultrasound test done, make a diagnosis, and begin treatment if it is required.

Treatment for CDH

The goal of treatment is to place the femoral head back into the acetabulum and keep it there until the structures surrounding the hip (muscles, ligaments, and tendons) become strong enough to hold joint together.

Method of treatment and results vary with the age of the child at the time of diagnosis. Generally, the younger the patient when diagnosed, the better prognosis. Both complexity of treatment and risk of complication tend to increase with age.

Treatment for CDH: Age 0 to 6 month

For typical CDH, treatment consists of bracing and splinting. Examples of equipment used include plastic-covered metal splints, abduction pillows, and cloth harnesses (N.B. triple diapers are not a reliable treatment method). Occasionally a spica cast may be used. A common treatment choice at this stage is the pavlik harness. Patients usually wear their treatment apparatus continuously for 2 to 4 months. After this period, a night splint may be used for 2 to 6 months to ensure that healing is complete. Treatment complication are rare for those with typical CDH in this age group.

About 15% of patients are not successfully treated with the harness and may require traction followed by a cast. A few require an operation.

For those with teratologic dislocation (a rare kind of stiff dislocation present before birth), treatment is more difficult. Muscle releases, traction, and open reduction (surgery) is often required. Surgery usually takes about 2 hours but varies with the complexity of the situation. The prognosis for normal joint development is poor.

Treatment for CDH: Age 8 to 18 months

Treatment of the older infant with previously undetected CDH is more difficult. Closed reduction (putting the hip back into the joint and holding it with a cast) can be attempted after a preliminary period of traction to stretch the tissues around the hip. Home traction may be required for 10 days to 3 weeks.

Treatment for CDH: Age 18 month to 4 years

Surgical treatment is almost always necessary for children diagnosed during this period. A combination of treatments may be required to achieve hip stability. These include traction, muscle release, open reduction, and innominate osteotomy (followed by a 6-week period of casting). Treatment at this stage is technically demanding, but the prognosis for long-term function is good.

Open reduction (surgery) may be required if closed reduction is not easily achieved. After reduction, the child is immobilized in a series of casts. From 4 to 8 months of cast treatment may be required for additional 4 to 6 months.

The majority of children treated with closed reduction and traction develop normal hips. In 10% of the children, however, avascular necrosis occurs (death of bone due to loss of blood supply).

Complications of treatment

The method selected may fail, and another may be needed. For example, if closed reduction is not successful, open reduction may required.
Redislocation
Avascular necrosis. This occurs when blood supply to the femoral head is temporarily lost. Without this circulation that part of the bone dies, as no nutrients are reaching it. Although recovery is usually spontaneous, the development of the hip may be affected.
Stiffness
Fracture after surgery
Residual subluxation. This means that the hip is in the joint but not as deeply as it should be.
Degenerative arthritis may develop later if these complication arise.

Tips for parents of CDH Patients

Don’t panic! Many surgical and treatment advances have been made in this field. Doctor who treat this condition are familiar with its details and have repeatedly demonstrated high levels of success in treating it.
Ask questions. You should discuss your child’s problem thoroughly with your doctor. Do not hesitate to ask him all the questions you may have. Write down your question ahead of time.
Become involved in your child’s treatment. you will be taught how care for your child to help in his or her recovery.
Follow directions regarding casting, braces, and harnesses carefully. Remove them only as directed by the physician.
If your child is in cast/brace/harness, keep it clean. This apparatus has a space for diapering, so keep the child’s perineal area (bottom) clean as well.
Continue to monitor and follow-up your child’s problem with your physician. This will allow for early detection and treatment should the condition recur.
Make a conscious effort to treat your child as normally as possible.
Encourage your child to resume normal activities as soon as is medically recommended.
Use all available resources, remember you are not in this alone. Many professionals are available to answer your questions or direct you to people who can help you.

Note: All content presented on this website is intended for informational purpose only. The information on this website should not be used as a basis for diagnosis or treatment without an examination by a medical practitioner.