Developmental dysplasia of the hip (DDH) is a spectrum of disorders characterized by abnormal development of the hip joint, ranging from mild acetabular dysplasia to complete dislocation of the femoral head. Early detection and intervention are crucial for optimal outcomes.

DDH affects approximately 1-3% of live births, with significant variation by ethnicity and geographic region. The condition can be detected through clinical screening in the neonatal period and confirmed with imaging studies.

DDH involves abnormal development of the acetabulum and femoral head, characterized by:

• Shallow acetabulum with decreased depth and increased inclination
• Instability of the hip joint allowing excessive movement
• Progressive deformity if untreated, leading to complete dislocation
• Bilateral involvement in up to 20% of cases

The developmental dysplasia occurs as the acetabulum and proximal femur fail to develop normal anatomical relationships, often related to intrauterine positioning, genetic factors, and ligamentous laxity.

Clinical manifestations vary significantly by age at detection:

• Neonatal period: May be asymptomatic; clinical signs include positive Ortolani and Barlow maneuvers
• Early infancy: Limited hip abduction, asymmetric gluteal folds, leg length discrepancy
• Late detection: Limp or waddling gait, hip pain, difficulty with movement
• Risk factors: Breech presentation, positive family history, female sex, oligohydramnios

Ultrasound (Preferred <6 months): Gold standard imaging modality. Measures acetabular coverage using Graf classification. High sensitivity and specificity without radiation exposure.

X-ray (>6 months): Anteroposterior view of pelvis. Measures acetabular index and other radiographic parameters indicating hip development.

MRI: Reserved for complex cases requiring detailed soft tissue evaluation.

Treatment depends on age at diagnosis and severity of dysplasia:

• 0-6 months: Pavlik harness (dynamic abduction splint)
• 6-18 months: Abduction bracing devices
• >18 months: May require surgical reduction and pelvic/femoral osteotomy

Success rates are highest with early intervention, particularly before 6 weeks of age.

Immediate actions:

• Refer immediately for hip ultrasound if clinical suspicion
• Avoid forced hip abduction or aggressive manipulation
• Ensure appropriate positioning and handling of infant
• Coordinate with pediatric orthopedics for specialist assessment

Monitor for progression of dysplasia, loss of stability, or development of complications. Bracing effectiveness should be assessed with serial imaging at 6-12 week intervals.

Bilateral DDH: Occurs in 20-40% of cases; may require simultaneous or sequential treatment.

Familial cases: Increased risk in siblings and offspring; recommend screening of first-degree relatives.

Associated syndromes: DDH more common in conditions with generalized joint laxity (Marfan syndrome, Ehlers-Danlos) or neuromuscular disorders (cerebral palsy).

Imaging stewardship: Use ultrasound as first-line imaging in children <6 months. Reserve X-ray for children >6 months or when ultrasound findings are equivocal.

Medication stewardship: Use paracetamol as first-line analgesia. NSAIDs should be reserved for post-operative use or when paracetamol is insufficient, with appropriate monitoring for adverse effects.

Specialist referral: All confirmed DDH cases should be referred to pediatric orthopedics. Early intervention within the first 6 weeks of life significantly improves outcomes and reduces need for surgery.

Early detection and treatment outcomes: When diagnosed and treated within the first 6 weeks of life, >90% of infants achieve stable, well-developed hips without surgical intervention.

Late diagnosis: Children diagnosed after 6 months may require surgical intervention (open reduction, osteotomy). Outcomes are less favorable, with higher rates of residual dysplasia and early-onset osteoarthritis.

Long-term follow-up: Children treated for DDH should be reviewed periodically throughout childhood to monitor for complications and ensure optimal hip development. Assessment should continue until skeletal maturity.

Complication monitoring: Assess for avascular necrosis, persistent dysplasia, contractures, and development of osteoarthritis symptoms in adolescence and adulthood.

• Australian Orthopaedic Association: Guidelines on developmental dysplasia of the hip
• American Academy of Pediatrics: Clinical practice guideline for DDH screening and diagnosis
• International Hip Dysplasia Institute: Evidence-based recommendations for DDH management
• eTG - Therapeutic Guidelines: Developmental dysplasia of the hip in children
• NICE Guidelines: Developmental dysplasia of the hip in children: assessment and management