The hip joint is a ball-and-socket structure wherein the femur’s head (ball) firmly fits into the hip socket (1). However, in some cases, the ball doesn’t fit into the hip socket properly, causing the hip joint to dislocate partially or completely. This rare musculoskeletal condition is known as hip dysplasia or developmental dysplasia of the hip (DDH).
According to the American Academy of Pediatrics (AAP), hip dysplasia in babies can be congenital or develop during infancy (2). The condition typically varies in severity and can occur in one or both hip joints. As a parent, knowing about the condition in detail can help in early diagnosis and prompt treatment for the baby.
This post shares about symptoms, diagnosis, treatment, and prevention of hip dysplasia in babies.
Signs And Symptoms Of Hip Dysplasia
Below are some of the common signs and symptoms of hip dysplasia in infants (3) (4).
- Both the legs are of different lengths, wherein the legon the affected side appears shorter
- Limited range of motion in the leg on the affected side, causing a limp while walking
- Uneven skin folds or creases in the thigh or hips
- Inability to move one or both legs correctly
- Clicking sensation during hip movement; a condition known as clicky hips
In older babies and young children, the most prominent signs are the following.
- Delay in standing or walking without assistance
- Body bent to one side while standing or walking
- Clumsy walking with limping or dwindling movement
Although hip dysplasia may develop in one or both hip joints, it commonly affects the left hip since it is believed that there is more pressure on it during fetal life (5) (6).
Possible Causes Of Hip Dysplasia
The definite cause of hip dysplasia is not known. The following risk factors may contribute to the development of the condition (3) (4) (6).
Hormones: Maternal hormonal changes during labor relax the mother’s ligaments and muscles for childbirth. Some babies could be sensitive to these hormones and may develop excessively relaxed joints, increasing the risk of hip dislocation. Girls tend to display greater ligament laxity, making them five times more likely to develop hip dysplasia than boys.
Breech position: Babies in the breech position (head up and legs towards the birth canal) are more prone to hip dysplasia. The breech position could stretch the baby’s legs inside the womb, affecting the normal development of the hip joint and increasing the risk of hip dysplasia.
Incorrect swaddling: Straightening the baby’s legs before swaddling could exert excess pressure on the hip joint, increasing the risk of hip dysplasia. A baby should have adequate room to move and bend their legs even when swaddled to prevent hip dislocation.
Genetics: According to the International Hip Displacement Institute, babies with a family history of hip dysplasia are 12 times more likely to develop the condition (6). If the parent had hip dysplasia, and so did their baby, there is a 36% chance of having another baby with the same condition.
Some other musculoskeletal conditions or deformities, such as foot deformities or neck stiffness (torticollis), may increase hip dysplasia risk. The reason is that these conditions may lead to space constraints in the womb, increasing the risk of other problems, including hip dysplasia.
Diagnosis Of Hip Dysplasia
Doctors and midwives check for the presence of hip dysplasia at different time intervals, such as baby’s birth, six weeks after birth, and when they begin to walk (4). In case a hip problem is suspected, further tests are conducted.
Physical examination: The doctor will examine the baby’s hip joints and ask about the birth position and any family history of hip problems. Your doctor will also listen and feel for “clicks” by maneuvering the hip. Based on the evaluation, the doctor can order diagnostic tests for further confirmation.
Ultrasound imaging: Ultrasound imaging or sonography evaluates the hip joint, focussing on the fusion of the femoral head (ball) and the socket. It helps determine if the dislocation is partial or complete and whether it needs any specific treatment. Sonograms are a suitable way to diagnose hip dysplasia in babies aged six months or younger.
X-rays: After six months of age, the cartilage starts to harden into bones. X-rays can help visualize the bones and joints in older babies. In some cases, the doctor may also suggest an MRI.
Treatment For Hip Dysplasia
The treatment for hip dysplasia depends on the baby’s age and the severity of the symptoms. The main aim of the treatment is to rectify joint dislocation and restore normal hip function (3) (4) (6) (7).
Wait and watch: The doctor may choose a wait-and-watch strategy if the baby is younger than three months and has mild hip dysplasia with a mostly stable hip. The reason is that babies have soft bones (cartilages) that are still developing, and these can fuse naturally over time without any medical intervention.
Pavlik harness: Babies with an unstable hip joint or shallow socket may require a Pavlik harness. It is a positioning device that holds the baby’s hip in place while allowing some leg movement. It is used on babies up to four months of age. In most cases, babies need to wear a Pavlik harness full-time for six to 12 weeks, with part-time wearing for a few additional weeks.
Abduction brace: If a Pavlik harness does not correct hip dysplasia, the baby may require a lightweight abduction brace, which supports the baby’s hips and pelvis. The baby may need to wear it for eight to 12 weeks.
If non-surgical interventions do not work, the baby could require adjustment of the hip bone under anesthesia or surgical correction.
Closed-reduction procedure: The baby is administered anesthesia. The doctor proceeds to perform an arthrogram, a procedure where a contrast agent is injected into the joint for better visibility during imaging tests, such as X-rays or MRI. The joint is manually adjusted to its correct position with the help of images from imaging tests — a procedure known as closed reduction. The baby’s legs and hips are then held in their correct position by a spica cast, which the baby wears for three to six months. A closed-reduction procedure may be preferred if the baby’s age is between six months and two years.
Open-reduction surgery: If the closed-reduction procedure does not correct hip dysplasia, the baby could need open-reduction surgery. In this surgery, the surgeon adjusts the hip to its correct position. Depending on the case’s severity, the surgery may include other procedures, such as reshaping the hip socket. After the surgery, your baby will wear a spica cast until they heal. Open-reduction surgery may be preferred if the baby’s age is more than two years.
After surgery, an orthopedist will periodically review the baby’s hip joint to ensure its normal development. Your doctor will also guide you about the appropriate ways to perform daily activities while the baby is wearing a cast. Once the baby’s hip joint is in its correct position, the cast is removed.
Possible Complications Of Hip Dysplasia
In most cases, early diagnosis and treatment help in the normal development of the hip joint. Below are some possible complications that may occur during treatment.
- Babies and toddlers with the spica cast may learn to walk later than their peers due to wearing the cast for a long time.
- Positioning devices, such as the Pavlik harness and abduction brace, may cause skin irritation around the straps in sensitive babies.
- Severe cases of hip dislocation may cause a permanent difference in leg length. In rare cases, the bone’s growth may be permanently affected due to hip dysplasia.
A higher chance of complications exists if treatment is started at a later age since bones and growth plates become harder with age.
Is Hip Dysplasia Preventable?
It may not always be possible to prevent hip dysplasia. You may take some precautions to avert the risk factors that increase hip dysplasia’s chances in babies.
- Avoid swaddling your baby too tightly. Remember, you need to snuggle your baby gently in the swaddling cloth such that they can move their legs freely.
- Keep up with your pediatrician’s appointments, especially during the first six months of the baby’s life. Many cases of hip dysplasia could be detected during a routine checkup.
- Place your baby in a baby carrier in the “M” position. This position allows the baby’s hip to spread in the squat format, preventing any strain on the hip joint.
Hip dysplasia in babies is a rare condition requiring prompt treatment. This condition in babies is painless but may turn painful and bothersome as they grow older. In most cases, timely diagnosis and appropriate treatment can help a baby lead an active, pain-free life.