In a normal hip joint, the rounded top of the thigh bone (femur) fits into a cup-shaped socket in the pelvis called the acetabulum. This type of joint is called a ball-and-socket joint.
In developmental dysplasia of the hip, the top of the femur moves in and out of the socket either part way or all the way. When it moves all the way out of the socket, it is called a dislocation. This happens when the ligaments that hold the two bones together are very loose or because the cup-shaped socket is not deep enough.
This condition usually is present at birth. But it can develop during infancy or childhood.
If the bones in the joint are not in the right place, the hip and femur can't grow normally. This can lead to:
- A shortened leg
- Difficulty walking
- Long-term pain
In an infant, developmental dysplasia of the hip can result in the following:
- One leg is shorter than the other.
- The right and left kneecaps are not at the same level when you look at both legs at the same time.
- One thigh has a different number or pattern of skin folds than the other.
- One leg moves less smoothly than the other.
Doctors routinely check for symptoms of developmental dysplasia of the hip during the first physical exam of a newborn. This happens within a day or two of birth. They also check at follow-up well-baby visits.
As part of the normal screening for this condition, your doctor will ask about risk factors. He or she will want to know whether your child was delivered in the breech position, is a firstborn, or if there is a family history of the condition in a parent or sibling.
The doctor checks your baby for developmental hip dysplasia by gently moving his or her legs while supporting and checking for movement in his or her hips. If the doctor feels enough movement of the hip, he or she may suspect either a hip dislocation or that the hip can be easily dislocated.
In this case, the doctor will confirm the diagnosis by ordering either an ultrasound or X-rays of your child's hip. Ultrasound is used in newborns and very young infants. That is because certain parts of the hip bones cannot be seen as clearly with regular X-rays until a child is 3 to 7 months old.
In difficult cases, especially in older children with developmental dysplasia of the hip, the doctor may need to order additional imaging tests. These may include a computed tomography (CT) scan, magnetic resonance imaging (MRI) scan or arthrogram. These tests can show greater detail of how the hip joint is put together.
Treatment lasts until the hip joint becomes stable and the child's ultrasound or X-ray studies are normal. This usually takes one to two months if the baby's dislocation was identified immediately after birth.
Developmental dysplasia of the hip can't be prevented. But the problems caused by it can. With early treatment, most cases can go away completely.
Screening guidelines call for all children through 18 months of age to be carefully examined. If dysplasia is suspected, ultrasounds or other tests should be done to look at the hip. And, the child should be seen by an orthopedist.
In all girls who were born breech or who have a family history of developmental dysplasia of the hip, the American Academy of Pediatrics (AAP) recommends an ultrasound at 6 weeks of age or regular X-rays at 4 months. Boys in either group have a lower risk. So the AAP doesn't recommend automatic testing, but says boys should be followed very closely.
Treatment of developmental dysplasia of the hip depends on the child's age:
- Newborns. Newborn babies usually wear a special orthopedic device, such as the Pavlik harness or the Frejka splint. These devices keep the top of the femur in the socket the right way. After a couple of months of treatment, the hip ligaments gradually tighten and the hip joint usually stabilizes.
- Infants age 1 month to 6 months. As in newborns, the doctor will begin treatment with a harness or splint. If these devices don't help, the doctor will consider gently putting the head of the femur in place while the child is under anesthesia. This procedure is done without surgery. It is called a closed reduction. The child then wears a body cast (spica cast) until X-rays show that the hip joint is normal.
- Children age 6 months to 2 years. Most children can be treated with closed reduction and a spica cast. Some require open surgery to correct the hip problem.
- Children older than 2 years. Often, by this time, the hip joint is very deformed and surgery is needed followed by a spica cast.
Call your doctor if:
- You notice that your baby has trouble moving one leg
- One of your baby's legs seems to be shorter than the other
Doctors routinely check for developmental hip dysplasia during well baby visits. Tell the doctor if your baby was delivered breech or there is a family history of hip problems.
If the hip problem is identified and treated early, the child should walk normally and have normal hip function.
American Academy of Pediatrics (AAP)
141 Northwest Point Blvd.
Elk Grove Village, IL 60007-1098
National Institute of Arthritis and Musculoskeletal and Skin Diseases
National Institutes of Health
1 AMS Circle
Bethesda, MD 20892-3675
American Academy of Orthopaedic Surgeons (AAOS)
6300 North River Road
Rosemont, IL 60018-4262
National Rehabilitation Information Center (NARIC)
4200 Forbes Blvd.
Lanham, MD 20706