DDH Progression and Monitoring
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
Investigations Provided
Laboratory Results
| Test | Result | Normal Range | Interpretation |
|---|---|---|---|
| N/A | - | - | Bloods not required for DDH assessment |
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
Explain the Graf ultrasound classification and what do these findings mean?
What is your initial management plan for this infant?
At 6 weeks, the left hip is still Graf IIc (alpha 49°). What are your options?
The patient is now 8 months old. Pavlik failed and she has a persistently dislocated left hip. What is your management?
The closed reduction failed due to interposed tissue. Describe your open reduction approach.
At age 3 years, the hip is reduced but there is persistent acetabular dysplasia. What are your options?
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:
| Age | Screening Method | Action |
|---|---|---|
| Birth | Clinical exam (Barlow/Ortolani) | If positive → ultrasound |
| 6-8 weeks | Clinical exam (selective US) | All at-risk or abnormal exam |
| 3-4 months | X-ray if US inconclusive | Ossific nucleus appears |
| >6 months | X-ray (pelvis AP) | US no longer useful |
Critical Management Points
- Graf classification determines treatment - Type I observe, Type IIa rescan, IIc+ treat
- Pavlik harness success rate 80-90% if started early and fitted correctly
- Don't persist with failed Pavlik - 4-6 weeks maximum, risk of "Pavlik disease"
- Closed reduction window 6-18 months - before this brace, after this surgery more likely
- Arthrogram is essential for closed reduction - confirms concentric reduction
- Residual dysplasia needs surgery if AI >30-35° - won't remodel spontaneously
Common Examiner Follow-ups
Q: "What are the risk factors for DDH?"
| Category | Risk Factors |
|---|---|
| Patient | Female (4:1), firstborn, breech, oligohydramnios |
| Family | First-degree relative with DDH (10x risk) |
| Associated | Torticollis, metatarsus adductus, calcaneovalgus foot |
| Syndromes | Down syndrome, Ehlers-Danlos, Larsen syndrome |
Left hip affected more often (left occiput anterior position compresses hip against sacrum).
Q: "What is the risk of AVN with DDH treatment?"
AVN risk by treatment:
| Treatment | AVN Risk |
|---|---|
| Pavlik harness (correct use) | 0-1% |
| Pavlik (overtightened/forced) | Up to 5% |
| Closed reduction | 5-15% |
| Open reduction (medial) | 10-20% |
| Open reduction (anterior) | 5-15% |
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
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
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.
Related Topics
- DDH Pavlik Failure
- DDH Treatment Options
- Pelvic Osteotomies (Salter, Pemberton)
- Developmental Dysplasia of the Hip
- Paediatric Hip Examination
- Graf Ultrasound Classification