What is developmental dysplasia of the hip (DDH)?

Developmental dysplasia of the hip (DDH) is a common condition affecting infants and young children. It involves abnormal development of the hip joint, which can lead to various complications if not treated promptly.

Here, Dr Claudia Maizen, renowned consultant paediatric orthopaedic and trauma surgeon, offers an expert insight into DDH.

What is DDH?

DDH is a condition present at birth where the hip joint doesn’t develop properly. The hip joint is a ball-and-socket joint, and in DDH, the socket (acetabulum) may be too shallow, allowing the ball (femoral head) to dislocate or be prone to dislocation.

The signs and symptoms of DDH can vary depending on the severity of the condition and the age of the child. However, common signs and symptoms include:

• uneven leg length, with one leg appearing shorter than the other
• limited range of motion in the affected hip, particularly when spreading the legs apart
• extra or uneven skin folds on the thigh or buttocks
• audible clicking or popping noises during movement of the hip joint
• limping or a waddling gait when walking

What are the causes of DDH?

The exact cause for DDH is unknown, but several factors are known to contribute to its development, including:

• Genetic predisposition: A family history increases the likelihood of a child developing the condition, as certain genetic markers may predispose to DDH.
• Breech position: Babies born in the breech position (buttocks first) are at higher risk of DDH due to the abnormal positioning of the hips during development.
• Oligohydramnios: Low levels of amniotic fluid during pregnancy can restrict fetal movement, contributing to hip dysplasia.
• Female sex: DDH is more common in females, possibly due to the influence of maternal hormones that relax the hip ligaments.

How is DDH diagnosed?

Early diagnosis of DDH is crucial for effective treatment and prevention of long-term complications. Diagnosis typically involves a combination of physical examinations as well as imaging tests.

Physical examination

• Ortolani and Barlow tests: The Ortolani test is used to check if a dislocated hip can be reduced back into the acetabulum (hip socket). The Barlow test is used to check if a stable hip can be dislocated. Both of these manoeuvrers are performed by a paediatric orthopaedic specialist to detect hip instability or hip dislocation in newborns and infants.
• Galeazzi test: The Galeazzi test is specifically used to assess for leg length discrepancies that may indicate hip abnormalities.

Imaging tests

• Ultrasound: Ultrasound is the preferred imaging method for diagnosing DDH in infants younger than six months. It provides a detailed view of the hip joint and can detect abnormalities.
• X-rays: X-rays help visualise the hip joint's structure and confirm the diagnosis of DDH. They are typically used for older infants and children.

What treatment options are available for DDH?

Treatment options include non-surgical and surgical methods. The choice of treatment will depend on the age of the child and the severity of the condition.

Conservative treatments

• Pavlik harness: The Pavlik harness is a soft brace that holds the baby's hips in a position that promotes proper development of the hip joint. It is typically used for infants younger than six months.
• Closed reduction and casting: For infants older than six months or those who don’t respond to the Pavlik harness, a closed reduction procedure may be performed. The hip is gently manipulated back into place, and a cast is applied to maintain the position.

Surgical treatments 

• Open reduction: In cases where closed reduction isn’t successful, an open reduction may be necessary. This involves surgically repositioning the hip joint.
• Osteotomy: Osteotomy is a surgical procedure that involves cutting and repositioning bones to enhance hip alignment. It may be combined with open reduction.
• Hip spica cast: After surgery, a hip spica cast is often applied to maintain the corrected position of the hip joint during the healing process.

Early intervention for DDH is essential to ensure the best possible outcome.

Will my child need physical therapy or rehabilitation post-treatment for DDH?

Post-treatment care is crucial for ensuring the success of DDH treatment and promoting proper hip development. Physical therapy and rehabilitation play a vital role in this process.

Physical therapy typically includes a range of motion exercises focused on increasing flexibility and preventing stiffness in the hip joint. Strengthening exercises are also prescribed to build muscle around the hip. In older children, gait training may be implemented to correct any abnormalities in walking patterns that have arisen due to DDH, ensuring improved mobility and proper alignment.

During rehabilitation, it’s crucial to maintain regular follow-up appointments with the paediatric orthopaedic specialist to monitor the hip's development and address any emerging issues promptly. Supportive devices like crutches or walkers may also be temporarily utilised to assist in mobility, tailored to the specific needs of the child undergoing treatment.

To schedule an appointment with Dr Claudia Maizen, head on over to her Top Doctors profile today.