Patient Information: Congenital Dislocation of the Hip (CDH)
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.