CIM Case: DDH - Pavlik Failure and Recurrent Dysplasia

Clinical Scenario

Patient: 5-month-old female infant Presentation: Referred with persistent left hip click and asymmetric thigh folds, treated in Pavlik harness for 6 weeks with no improvement Relevant history: Breech presentation, first-born female, family history of DDH (maternal aunt), started Pavlik at 6 weeks after failed Ortolani test, harness worn 23 hours/day, compliant family Examination findings:

• Left hip: Positive Barlow (dislocatable), Ortolani negative (irreducible)
• Asymmetric skin folds (more creases on left)
• Apparent limb length discrepancy (left shorter)
• Limited abduction left hip (40° vs 70° right)
• Right hip: Clinically stable
• No other abnormalities on general examination

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Investigations Provided

Imaging

Image 1: Hip Ultrasound (Graf Classification)

Sonographic features:

• Left hip: Graf Type IV (severely dysplastic, dislocated)
• Alpha angle: 38° (normal >60°)
• Beta angle: 85° (normal <55°)
• Femoral head position: Dislocated, lying superiorly
• Acetabular coverage: Poor, labrum everted
• Right hip: Graf Type I (normal)

Image 2: AP Pelvis Radiograph

Radiological features:

• Hilgenreiner's line drawn
• Left hip: Femoral ossific nucleus absent (normal at this age)
• Left acetabular index: 42° (abnormal >30°)
• Shenton's line: Broken on left
• Perkin's line: Left femoral metaphysis in superior-outer quadrant
• Right hip: Normal acetabular index (25°), Shenton's line intact

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Questions & Model Answers

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Key Teaching Points

Pattern Recognition

This pattern suggests DDH Pavlik Failure:

• Infant in Pavlik harness without improvement
• Graf Type III/IV on ultrasound
• Ortolani negative (irreducible)
• Persistent dislocation after 3-4 weeks treatment

Risk Factors for Pavlik Failure:

Critical Management Points

1. Stop Pavlik if no improvement by 3-4 weeks - prevents Pavlik harness disease
2. Alpha angle >60° is normal - Graf Type I
3. Closed reduction first - unless clear contraindication
4. Safe zone >30° - or risk of AVN
5. Follow until skeletal maturity - residual dysplasia may develop
6. Pelvic osteotomy for residual dysplasia - Salter or Pemberton

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Common Examiner Follow-ups

Q: "What is the safe zone and why is it important?"

The safe zone is the arc of hip motion from maximum abduction (before impingement/AVN risk) to minimum abduction (before dislocation). It should be >30° for safe casting.

Importance:

• Documents stable arc where hip is reduced without excessive pressure
• If <30°, AVN risk is high - may need adductor tenotomy or open reduction
• Used to determine casting position

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Q: "What is Pavlik harness disease?"

Pavlik harness disease is damage to the posterior acetabulum caused by continued Pavlik harness use in an irreducible hip. The dislocated femoral head presses against the posterior acetabular rim, causing erosion. Prevention: discontinue Pavlik if no reduction by 3-4 weeks.

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Q: "What is the difference between Salter and Pemberton osteotomies?"

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Q: "What radiographic measurements do you use in DDH?"

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Related Topics

• DDH Screening and Diagnosis
• Pavlik Harness Application
• Open Reduction of DDH
• Pelvic Osteotomies in DDH
• AVN of Femoral Head
• Residual Hip Dysplasia