DDH

Developmental Dysplasia of the Hip (DDH)

Developmental dysplasia of the hip (DDH) is an umbrella term for a range of conditions where the “ball and socket” joint of the hip does not form correctly. This can result in a dislocated, dislocatable, or subluxated hip, often accompanied by acetabular dysplasia. Early diagnosis and management are crucial for a better outcome and to prevent long-term complications.

 

Risk Factors

DDH is seen in about 1% of babies and is more common in first-born girls. The main risk factors include:

  • Family History: A sibling or first-degree relative with DDH increases the risk.

  • Intrauterine Positioning: Breech presentation at birth is a significant risk factor. Other factors include oligohydramnios and multiple pregnancies.

  • Neuromuscular Conditions: Conditions like meningomyelocele or cerebral palsy can also be associated with DDH.

 

Clinical Assessment

A comprehensive clinical assessment is essential, especially during routine newborn checks.

  • Barlow and Ortolani Tests: These tests are performed on infants under 3 months of age to assess for hip instability. The Barlow manoeuvre attempts to dislocate an unstable hip by pushing it backwards, while the Ortolani manoeuvre reduces a dislocated hip with a palpable “clunk”.

  • Older Infants and Children:

    • Asymmetrical Skin Folds: Uneven thigh skin folds or a flattened buttock fold can be a sign of DDH.

    • Galeazzi’s Sign: A leg length discrepancy can be noted when the hips and knees are flexed at 90 degrees.

    • Reduced Hip Abduction: The most reliable sign in older infants is a reduced range of motion, particularly a limited abduction of the hip when semi-flexed.

    • Gait Abnormalities: In older children who are walking, a painless limp, waddling gait, or walking on tiptoes may be noted. A positive Trendelenburg sign may also be present.

 

Investigations

  • Ultrasound: This is the primary imaging modality for infants under 6 months of age, as the femoral head is not yet ossified. Ultrasound provides a dynamic assessment of hip stability and acetabular development.

  • X-ray: A pelvic X-ray is the investigation of choice in children older than 6 months, once the femoral head ossification centre has developed.

  • MRI: MRI may be used in more complex cases to assess the hip anatomy in detail.

 

Management

Early diagnosis leads to a better prognosis.

  • Bracing: In infants younger than 6 months, the primary treatment is an abduction splint, most commonly a Pavlik harness. This holds the hips in a flexed and abducted position, allowing the joint to develop correctly.

  • Closed Reduction and Spica Cast: For babies between 6 months and 18 months, or those who fail harness treatment, a closed reduction under anaesthesia followed by a spica cast is often required for milder cases.

  • Surgical Intervention: Open reduction is performed for children who do not respond to closed reduction or are diagnosed late. In older children, an osteotomy may be necessary to correct the bone deformities and properly position the hip in the socket.