How do you assess for Developmental Dysplasia of the Hip (DDH)?

Assessment of Developmental Dysplasia of the Hip (DDH)

The assessment for Developmental Dysplasia of the Hip (DDH) requires age-appropriate physical examination maneuvers and imaging, with ultrasound being the preferred imaging modality for infants under 4 months and radiography for those over 4 months of age. 1

Clinical Examination Techniques

For Infants Under 3 Months

• Ortolani Test:

  • Position: Infant supine with hips and knees flexed at 90°
  • Technique: Abduct the hip while gently lifting the greater trochanter anteriorly
  • Positive finding: A palpable "clunk" as the dislocated femoral head reduces into the acetabulum 1

• Barlow Test:

  • Position: Infant supine with hips and knees flexed at 90°
  • Technique: Adduct the thigh while applying gentle posterior pressure on the knee
  • Positive finding: Sensation of the femoral head dislocating posteriorly
  • Follow by lifting the thigh upward while abducting to relocate the femoral head 1

For Infants Over 3 Months

• Limited Hip Abduction: Most important screening method as Barlow and Ortolani tests become less reliable 1

  • Technique: Attempt to abduct both hips with knees flexed
  • Positive finding: Asymmetric or limited abduction (positive predictive value increases to 55% after 8 weeks) 1

• Additional Signs:

  • Asymmetric skin folds in the proximal thigh
  • Limb length discrepancy (apparent shortening on affected side)
  • Galeazzi sign (knee height asymmetry when hips and knees are flexed) 1

For Walking Children

• Observe for:
  • Typical limp with toe-walking on the affected side
  • If bilateral: increased lumbar lordosis, prominent buttocks, and waddling gait 1

Imaging Assessment

Ultrasound Evaluation (0-4 months)

• Timing: Perform after 2 weeks of age (before this, normal laxity may lead to false positives) 1
• Technique: Use high-frequency linear array transducer 2
• Methods:
  • Graf method: Assesses morphology and measures alpha and beta angles
  • Dynamic examination: Applies physical maneuvers to assess hip stability 2
• Advantages:
  • Visualizes cartilaginous components not seen on radiographs
  • Higher sensitivity (77%) and positive predictive value (49%) compared to clinical examination alone (62% and 24%, respectively) 1

Radiographic Evaluation (>4 months)

• Timing: Becomes reliable after 4-6 months when femoral head ossification begins 1
• Views:
  • Anteroposterior view with hips in neutral position
  • Von Rosen view (legs at 45° abduction with internal rotation) to accentuate dislocations
  • Frog-leg view to assess reduction when neutral view is abnormal 1
• Assessment:
  • Relationship of ossific nucleus of femoral head to acetabulum
  • Position of proximal femoral metaphysis
  • Acetabular index measurement (though has significant measurement variability) 1

Risk-Based Assessment Algorithm

1. All newborns: Clinical examination at birth
2. High-risk infants (female gender, breech position, family history, firstborn):
   • Clinical examination at birth
   • Consider ultrasound at 4-6 weeks even with normal exam 3
3. Positive Ortolani/Barlow test:
   • Ultrasound confirmation (reduces unnecessary treatment by 41-58%) 1
   • Referral to orthopedist if confirmed
4. Equivocal findings at birth:
   • Re-examination in 2 weeks
   • If persistent beyond 6 weeks, orthopedic evaluation 4
5. Follow-up schedule for all infants:
   • Hip examination at well-baby visits (2 weeks, 2,4,6,9, and 12 months) 5
   • If concerns arise, ultrasound if <4 months or radiograph if >4 months 5

Common Pitfalls and Caveats

• False positives: 60-80% of abnormalities on physical exam and >90% on ultrasound resolve spontaneously 1
• False negatives: Normal neonatal exam does not guarantee normal hip development; continued surveillance is essential 5
• Age-appropriate assessment: Ortolani/Barlow tests lose reliability after 3 months; limited abduction becomes more important 1
• Imaging limitations:
  • Ultrasound may be too sensitive, potentially leading to overtreatment 5
  • Radiographs have limited value before 4 months due to unossified femoral heads 1
• Examination expertise: The sensitivity and specificity of clinical examination depend heavily on the examiner's experience 1

By systematically applying these assessment techniques based on the infant's age and risk factors, clinicians can effectively identify and manage DDH, reducing the risk of long-term complications such as early-onset hip osteoarthritis in adulthood 4.