CIM Case: DDH Progression and Monitoring

Clinical Scenario

Patient: 2-week-old girl Presentation: Referred from postnatal check - left hip "clunky" on Barlow test, right hip feels loose, family history of DDH (mother treated in infancy) Relevant history: First-born female, breech presentation until 36 weeks then cephalic, normal vaginal delivery at term, no oligohydramnios, no other congenital anomalies, feeding well Examination findings:

• Left hip: Positive Barlow (dislocatable), negative Ortolani (already reduced)
• Right hip: "Loose" feel, stable but lax
• No leg length discrepancy observed
• Symmetric thigh folds (unreliable sign)
• No associated spine abnormality
• Other joints normal

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Investigations Provided

Laboratory Results

Imaging

Image 1: Bilateral Hip Ultrasound (Age 2 weeks)

Left Hip:

• Alpha angle: 48°
• Beta angle: 68°
• Graf Type IIc (dysplastic, unstable)
• Femoral head coverage: 35%
• Acetabular roof: Concave but shallow
• Head position: Eccentric but reducible

Right Hip:

• Alpha angle: 54°
• Beta angle: 62°
• Graf Type IIa (immature but stable)
• Femoral head coverage: 42%
• Acetabular roof: Mildly shallow
• Head position: Concentric

Overall Impression: Left hip dysplastic and unstable requiring treatment. Right hip immature, may normalise with observation.

Questions & Model Answers

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Key Teaching Points

Pattern Recognition

This pattern suggests DDH requiring intervention:

• Female, breech, family history (classic risk factors)
• Clinical instability (Barlow/Ortolani positive)
• Graf Type IIc or worse on ultrasound
• Alpha angle <50° = dysplastic

DDH Screening Timeline:

Critical Management Points

1. Graf classification determines treatment - Type I observe, Type IIa rescan, IIc+ treat
2. Pavlik harness success rate 80-90% if started early and fitted correctly
3. Don't persist with failed Pavlik - 4-6 weeks maximum, risk of "Pavlik disease"
4. Closed reduction window 6-18 months - before this brace, after this surgery more likely
5. Arthrogram is essential for closed reduction - confirms concentric reduction
6. Residual dysplasia needs surgery if AI >30-35° - won't remodel spontaneously

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Common Examiner Follow-ups

Q: "What are the risk factors for DDH?"

Left hip affected more often (left occiput anterior position compresses hip against sacrum).

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Q: "What is the risk of AVN with DDH treatment?"

AVN risk by treatment:

AVN Prevention:

• Avoid forced abduction >70°
• "Human position" in spica (not frog position)
• Limit traction time
• Adequate safe zone before spica
• Femoral shortening if tight reduction

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Q: "When would you do a femoral osteotomy in DDH?"

Femoral Shortening Osteotomy:

• Required if closed reduction produces excessive pressure
• Common in late-presenting DDH (>2 years)
• Performed at time of open reduction or pelvic osteotomy
• Reduces risk of AVN

Femoral Varus Derotation Osteotomy:

• If coxa valga (neck-shaft angle >150°)
• If excessive femoral anteversion (>40°)
• Improves femoral head coverage
• Often combined with pelvic osteotomy

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Q: "What is the natural history of untreated DDH?"

• Infancy: May walk late but often mobile
• Childhood: Limp, Trendelenburg gait, LLD
• Adolescence: Pain begins, activity limitation
• Adulthood: Early secondary osteoarthritis (by age 30-40)
• Long term: Often requires hip replacement in 4th-5th decade

Early treatment prevents this cascade. Goal is concentric reduction and adequate acetabular development before skeletal maturity.

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Related Topics

• DDH Pavlik Failure
• DDH Treatment Options
• Pelvic Osteotomies (Salter, Pemberton)
• Developmental Dysplasia of the Hip
• Paediatric Hip Examination
• Graf Ultrasound Classification