What is Developmental Dysplasia of the Hip? What Are the Symptoms? How is It Diagnosed and Treated?

Developmental dysplasia of the hip is a common health problem in newborns and infants. More frequently observed in female infants, this condition occurs as a result of improper development of the baby's hip joint. Permanent disabilities can be prevented with early diagnosis and treatment, but it can lead to serious complications if neglected. In this article, you will find answers to what developmental dysplasia of the hip is, its causes, symptoms, how it is diagnosed, and how it is treated.

What is Developmental Dysplasia of the Hip?

Developmental dysplasia of the hip is a common orthopedic problem characterized by abnormal development and instability of the hip joint. It is one of the most frequently encountered musculoskeletal anomalies during childhood. It encompasses hip abnormalities present during the neonatal period or developing as the baby grows.

In our country, the incidence rate in newborns ranges between 0.86% and 17%. This wide range reflects regional differences and the variety of screening methods. Worldwide, between 1.5 and 28.5 out of every 1,000 live births encounter this problem.

Structure of the Hip Joint

The hip joint is one of the largest and strongest joints in the body. It has a ball-and-socket structure and consists of two main bones. The thigh bone, the femur, carries a ball-shaped head at its upper part. The acetabulum located in the pelvic bone acts as a socket to grasp this ball.

In a healthy hip joint, the femoral head fits completely into the acetabulum. The socket is sufficiently deep and firmly grasps the ball. The joint surfaces are covered with a slippery cartilage tissue, which facilitates movement. Thanks to this harmony, both body weight is supported and a wide range of motion is provided for the legs.

Degrees of Dysplasia

Developmental dysplasia of the hip has a wide spectrum. It is seen in different degrees, ranging from mild acetabular insufficiency to complete hip dislocation. In some babies, the socket is simply shallower than normal. In other words, the joint is unstable, but the femoral head has not yet dislocated.

In more advanced cases, subluxation occurs. The femoral head does not fully sit in the acetabulum, but it does not come out completely either. In the most serious case, a complete dislocation is present and the femoral head is completely separated from the acetabulum. Acetabular dysplasia can also be defined radiologically along with increased femoral valgus and anteversion.

Even cases that do not show clinical findings can develop permanent deformities if left untreated. Therefore, early diagnosis is of great importance.

Difference Between Congenital Hip Dislocation and Dysplasia

In the past, the term "congenital hip dislocation" was used. However, this definition is inadequate today. The expression "developmental dysplasia of the hip" is now more common.

There is an important reason for this change in terminology. The old term only covered complete dislocation cases. However, the problem is not limited only to dislocations present at birth. In some cases, the joint appears normal initially, but dysplasia develops as the baby grows. Radiological classification therefore holds a much more important place.

What Are the Causes and Risk Factors of Developmental Dysplasia of the Hip?

Although the exact causes are not fully known, developmental dysplasia of the hip is a condition that develops due to multiple factors. Genetic predisposition, mechanical factors during pregnancy, and postnatal environmental conditions play a role together. Knowing the risk factors is of great importance in terms of early diagnosis and taking precautions.

Genetic Factors

Family history significantly increases the risk of developmental dysplasia of the hip. If one of the parents has this problem, the probability of it appearing in the first child is 6 times higher compared to the normal population. The situation can become even more serious. If dysplasia is present in both the parent and the first child, the risk rises up to 36 times in the next child.

The genetic effect is not tied to a specific chromosome. Instead, a multigenic predisposition is mentioned. Connective tissue laxity can be inherited and this condition is seen in 6% to 7% of the population.

In-Utero Position

The baby's position inside the womb is an important factor in the development of dysplasia. While breech presentation birth is between 2% and 3% in the normal population, this rate is 6 to 7 times higher in babies with developmental dysplasia of the hip. Especially when both knees are straight, the risk reaches approximately 20%.

The left hip is affected more frequently than the right hip. Since the baby's left hip faces the mother's spinal protrusion while lying down, this side is subjected to twice as much pressure.

A scarcity of amniotic fluid called oligohydramnios is also among the risky conditions. When the fluid decreases, the baby cannot move comfortably and gets stuck somewhere. Similarly, multiple pregnancy and high birth weight (more than 4.5 kg) also increase the risk as they reduce the intrauterine volume.

Gender and Hormonal Effects

Developmental dysplasia of the hip is distinctly more common in female babies compared to male babies. It has been understood that maternal relaxin hormone is more effective in female children. This hormone is secreted to relax the ligaments in the birth canal. However, it also affects the connective tissue in the baby and leads to laxity in the hip joint.

Delivery Method and Complications

Breech presentation birth is an important risk factor. In addition, since the intrauterine space is more limited in first pregnancies, the risk is slightly higher in first-born babies. The thought that cesarean delivery causes developmental dysplasia of the hip is not true.

Swaddling and Environmental Factors

Postnatal practices can be decisive in the development of dysplasia. Swaddling babies in a way that wraps their legs tightly and straight increases the tendency for dislocation in the hip joint. Any practice that keeps the hips in a straight and closed position is harmful.

Tight swaddling fixes the legs in extension and closed position. This situation prevents the femoral head from developing within the socket. If swaddling is to be done, half-swaddling that naturally allows the legs to remain open must be preferred.

What Are the Symptoms of Developmental Dysplasia of the Hip?

Recognizing the symptoms is not always easy. Developmental dysplasia of the hip does not cause pain in babies and can be difficult to detect in the early period. Therefore, regular doctor check-ups are of great importance. Specialist physicians check the hips of all babies during routine examinations to look for symptoms of developmental dysplasia of the hip.

Symptoms in the Newborn Period

One of the first noticeable signs in newborn babies is the irregular appearance of skin folds in the leg and hip region. Folds in the thigh and hip skin should be symmetrical. However, asymmetry may indicate that the femoral head is not properly seated. Although skin folds alone are not a reliable finding, they provide an important clue when evaluated together with other symptoms.

Hearing a clicking or popping sound when the hip joint is moved is a striking finding. The doctor may notice this sound while checking whether the hip is seated in its place during the baby's examination. Difficulty for the baby in opening or bending the legs is also one of the early signs.

Symptoms in the Infant and Childhood Period

As the baby grows, symptoms become more pronounced. A length difference between the two legs may occur. The leg on the affected side appears shorter compared to the other. The formation of dislocation causes the hip to appear short.

Restriction in hip movements is observed. A situation where the legs cannot be opened outward or fully bent emerges. Children may feel discomfort when opening or bending their legs. Stiffness in the hip region restricts these movements.

Babies' legs may be in different positions than normal. For example, the legs may not open symmetrically or one may stand higher than the other. The leg on the side of the dislocated hip appears turned outward. The space between the legs can be much wider than normal.

Delay in gross motor development such as sitting and crawling is observed. Delays occur in the development of motor skills. The incompatible position of the hip joint slows down the motor development process by restricting the child's movements.

Signs Seen in the Walking Period

Starting to walk is delayed. Limping may be observed in the process starting with late walking. Shuffling is experienced in walking babies. Since one leg is shorter than the other, normal walking is impaired.

Walking on tiptoes or waddling is observed. A duck-like walking style may emerge. During walking, one hip joint moves differently from the other. There is a leaning towards one side while walking. Some babies progress by dragging their affected leg.

How is Developmental Dysplasia of the Hip Diagnosed?

The diagnostic process is carried out together with physical examination and imaging techniques. Hip examination is performed during regular check-ups in newborn babies, and if any abnormality is detected, further tests are requested.

Physical Examination Methods

Physical examination is of great importance in the newborn period. Hip examination in the first weeks of babies' lives is performed as part of routine check-ups. The two most commonly used tests in this examination are known as the Ortolani and Barlow maneuvers.

If the Ortolani test is positive, it indicates that the hip is dislocated. The Barlow maneuver reveals that the femoral head escapes from the acetabulum. However, the sensitivity of these tests is low and their positive predictive value is limited. DDH diagnosis can be missed up to 60%.

In babies older than three months, the Ortolani and Barlow tests become less reliable. Therefore, clinical symptoms such as asymmetric or limited hip abduction are sought. A clicking sound in the hip, restriction of movement in the hip, asymmetry in thigh folds, and leg length inequality are supportive physical examination findings in making a diagnosis.

Diagnosis with Ultrasonography

Hip ultrasound is the most reliable method in the diagnosis of DDH in the newborn period. It is the preferred imaging technique, especially for babies younger than four months. Hip ultrasonography is the most accurate and reliable diagnostic method in the first six months of life.

Ultrasound is a definitive diagnostic method completed in a short time without any harm to the baby. Static and stress images are taken with high-frequency ultrasonography. It is used to measure the degree of femoral head coverage and acetabular angles. Graf classification is commonly used to categorize dysplasia severity.

In our country, the Ministry of Health has accepted that the most appropriate age for hip ultrasonography for screening purposes is around 1 month. The specificity and sensitivity of ultrasonography are above 90%.

Evaluation with X-Ray

X-rays are used to evaluate the structure of the hip joint in babies and children older than six months. It is preferred for babies older than 4-6 months, where the secondary ossification center within the femoral head forms.

Measurements such as the acetabular index, Hilgenreiner's line, and Shenton's line are used to evaluate the degree of dysplasia. X-rays are sufficient to confirm hip joint dislocation or dysplasia.

Importance of Early Diagnosis

The most appropriate period for diagnosis and treatment is the newborn period. Early diagnosis is possible with hip ultrasound routinely performed on all babies. If treatment is carried out in the first 6 months, the complete recovery rate is close to 100%.

Early diagnosis and treatment are preferred because non-surgical methods are more effective. A large portion of DDH can be fully treated thanks to early diagnosis, with no negative impact on the individual's future life.

How is Developmental Dysplasia of the Hip Treated?

The treatment approach is determined according to the baby's age and the severity of the disease. The main goal is to ensure that the hip joint sits in the proper position and to maintain this condition. Early intervention significantly increases the chance of success.

Treatment in Babies Between 0-6 Months

The Pavlik harness is the most commonly used treatment method in babies younger than six months. This special orthosis keeps the hip in a slightly bent position and prevents it from closing inward. It consists of a chest strap, shoulder straps, and foot straps.

The harness is worn while the baby is lying on their back. First, the chest straps are passed from the nipple level. A three-finger space should be left between the strap and the chest. Otherwise, it becomes difficult for the baby to breathe comfortably.

The harness remains continuously worn for the first three weeks. At the end of the third week, a control is performed with ultrasound. Frequent examinations are required in the first days. After two-three days, one week, and two weeks, it should be checked whether the harness is being used correctly.

If reduction is achieved, the hip joint generally becomes stable within 4-6 weeks. The harness can be applied up to 9-12 months. However, if dislocation still persists at the end of the third week, another treatment method is switched to.

Treatment Approaches in Babies Over 6 Months

After six months, the chance of success of non-surgical methods decreases. Treatment is frequently performed by hospitalizing the patient.

Closed reduction is a widely applied method. The baby's hip joint is put back into place under anesthesia. Then, by giving the appropriate position, a pelvipedal cast is wrapped. This cast fixes the trunk and legs.

If sufficient recovery cannot be achieved with closed reduction, open reduction may be required. In this procedure, the hip joint is surgically opened, excess tissue inside the joint is cleaned, and the hip is put back into place.

Surgical Treatment Options in Children

Bone surgeries come into play in children after eighteen months. Pelvic osteotomy provides better coverage by changing the shape of the hip socket. Femoral osteotomy increases harmony by correcting the angle of the thigh bone.

As the child's age increases, the chance of treatment success decreases. The permanent effects left by the disease also increase.

Post-Treatment Follow-up Process

Treatment takes a long time and requires patience. The family's adherence to the treatment directly affects success. Follow-up must continue at intervals determined by the doctor until the child reaches adulthood.

Frequently Asked Questions

Families wonder about the answers to many questions when their babies are diagnosed with developmental dysplasia of the hip. In this section, you will find clear and concise answers to the most frequently asked questions.

Is developmental dysplasia of the hip permanent?

With early diagnosis and appropriate treatment, developmental dysplasia of the hip can be corrected. Most children can develop normally without experiencing any problems. Especially if treatment is started within the first six months, the complete recovery rate is close to 100%.

However, if left untreated, it can lead to permanent disabilities. Insufficiency in the joint will be permanent. Therefore, early intervention directly determines success.

What happens if it is not treated?

Developmental dysplasia of the hip does not heal on its own. In untreated cases, it can damage the soft cartilage in the hip joint. Along with this, it increases the likelihood of developing osteoarthritis in individuals.

Limping walking emerges. Pain in the hip starting at young ages is seen. Permanent restriction in joint movements occurs. Joint deterioration, commonly known among the public as calcification, turns into a painful and progressively less mobile condition over time.

Untreated developmental dysplasia of the hip is the cause of 30% of all total hip replacement surgeries under the age of 40 in adults. Cases that are not successfully treated in early childhood can cause severe pain that may require total hip replacement surgery later in life.

At what age should it be diagnosed?

Examination for developmental dysplasia of the hip should be performed by a specialist physician within the first month after birth. Within 72 hours after birth, the baby's hips are checked as part of the newborn examination.

The subsequent hip examination is performed when the baby is 6-8 weeks old. Screenings continue at regular intervals until the baby is 1 year old. In our country, the Ministry of Health has accepted that the most appropriate age for hip ultrasonography for screening purposes is around 1 month.

It can also be diagnosed during childhood. However, being diagnosed and treated in the early period yields more effective results.

How long does the treatment process last?

The duration of treatment varies according to the baby's age and the severity of the condition. In the first 6 months, treatment is possible with only a splint and some simple precautions. The Pavlik harness generally stabilizes the hip joint within 4-6 weeks. The harness can be applied up to 9-12 months.

In babies older than 6 months, a surgical procedure under general anesthesia is required. Cast application is performed afterwards. Following treatment, the patient is taken into follow-up.

Children should be monitored until they reach the age of 14-16. Results can vary from person to person in every surgical or interventional procedure. Therefore, long-term follow-up is required.

In Summary, Developmental Dysplasia of the Hip

Although developmental dysplasia of the hip may seem scary at first glance, it is a condition that can be completely treated with early diagnosis. The success rate in treatment started within the first six months approaches 100%. Therefore, it is of great importance not to neglect your baby's regular doctor check-ups.

Thanks to hip examination and ultrasound screenings, the problem is detected in time. When you continue treatment appropriately, your child can lead a normal life. However, when neglected, it can lead to permanent disabilities. If you notice any suspicious symptoms in your baby, consult a specialist physician immediately. Acting early is the most valuable step for your child to attain a healthy future.