# 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 **Graf Ultrasound Classification:** **Technique:** - Dynamic ultrasound examination - Coronal view through acetabulum - Measures alpha angle (bony roof) and beta angle (cartilaginous roof) - Performed in lateral decubitus position **Classification:** | Type | Alpha Angle | Beta Angle | Description | Management | |------|-------------|------------|-------------|------------| | **I** | ≥60° | <55° | Normal, mature hip | Discharge | | **IIa** | 50-59° | 55-77° | Immature (age <3 months) | Observe, repeat 4-6 weeks | | **IIb** | 50-59° | 55-77° | Immature (age >3 months) | Treat as dysplasia | | **IIc** | 43-49° | <77° | Critically dysplastic | Pavlik harness | | **IId** | 43-49° | >77° | Decentering (unstable) | Pavlik harness | | **III** | <43° | >77° | Dislocated, cartilage roof | Pavlik or rigid abduction | | **IV** | <43° | >77° | Dislocated, inverted labrum | Often requires surgery | **This Patient's Interpretation:** **Left Hip (Type IIc):** - Alpha 48° = shallow bony roof - Beta 68° = adequate cartilage coverage - "Critically dysplastic" - at threshold - Requires immediate treatment (Pavlik harness) **Right Hip (Type IIa):** - Alpha 54° = mild immaturity - Age <3 months = "physiological immaturity" - May normalise spontaneously - Repeat scan in 4-6 weeks > **Consultant Tip:** Alpha angle measures bony acetabular development. <50° is dysplastic. Graf IIc is the "don't miss" category - looks stable but needs treatment. **Immediate Management:** **Left Hip (Graf IIc):** - **Pavlik harness** - fitted immediately - Maintained in flexion (100-110°) and abduction (50-70°) - Full-time wear initially (23 hours/day) **Right Hip (Graf IIa):** - Observation within Pavlik (treating left anyway) - Will benefit from abduction positioning - Repeat scan to confirm normalisation **Pavlik Harness Protocol:** **Fitting:** - By trained practitioner - Chest strap at nipple level - Anterior straps allow flexion to 100-110° - Posterior straps allow abduction to 50-70° - Knees should be able to extend fully - Avoid forced abduction >70° (AVN risk) **Monitoring:** | Time | Assessment | |------|------------| | 1 week | Check fit, skin, hip position | | 2 weeks | Clinical assessment, adjust straps | | 3-4 weeks | Repeat ultrasound | | 6 weeks | Ultrasound, assess response | **Success Criteria at 6 weeks:** - Graf Type I (alpha ≥60°) - Clinically stable hip - Ortolani negative **Weaning (if successful at 6 weeks):** - Reduce to 12 hours/day for 4-6 weeks - Then night-time only for 4-6 weeks - Total treatment 3-4 months **Parent Education:** - How to check harness position - Nappy changes within harness - Bathing schedule (once daily, harness off briefly) - Skin care under straps - What to look for (strap migration, skin breakdown) > **Consultant Tip:** Most DDH (80-90%) resolves with Pavlik harness if started early. The key is fitting correctly - overtightening causes AVN. **Pavlik Harness Failure - Definition and Options:** **Definition of Failure:** - No improvement in alpha angle after 3-4 weeks - Persistent instability - Hip remains dislocated in harness - Development of "Pavlik harness disease" (posterior subluxation from forced abduction) **This Patient:** Partial response - still dysplastic but stable **Management Options:** **Option 1: Continue Pavlik (Reasonable):** - If hip is STABLE and reducing in harness - Alpha angle slowly improving (even if <60°) - May continue for another 4-6 weeks - Maximum Pavlik duration typically 4 months **Option 2: Rigid Abduction Brace:** - Von Rosen splint or Rhino brace - Maintains flexion and abduction - Better for infants who slip out of Pavlik - Often used for "stepping down" from Pavlik **Option 3: Closed Reduction and Spica (if 3-6 months old):** - Examination under anaesthesia (EUA) - Arthrogram to assess reduction - Closed reduction attempt - Hip spica cast for 3 months (6 weeks, reapply, 6 weeks) **This Patient's Recommendation:** - Alpha improved from 48° to 49° - some response - Hip is stable in harness - Continue Pavlik for further 4 weeks - If still IIc at 10 weeks, consider rigid brace or MUA **When to Abandon Pavlik:** - No improvement after 4 weeks - Worsening position - Skin breakdown - Age >6 months (harness less effective) **Red Flag - Pavlik Harness Disease:** - Hip develops posterior subluxation - From forced abduction with inadequate flexion - Must cease immediately - Rest hip for 2-3 weeks before other treatment > **Consultant Tip:** Pavlik failure rate is 5-15%. Don't persist beyond 4-6 weeks of no improvement. Age >3 months at start = higher failure rate. **Closed Reduction Under Anaesthesia (MUA/EUA):** **Age 6-18 Months - Closed Reduction Window:** - Safe window for closed reduction attempt - Before this: Pavlik/bracing preferred - After this: Open reduction more likely needed **Technique:** **Preoperative:** - Skin traction for 1-2 weeks (controversial - decreasing use) - Adductor tenotomy often performed - Consent for open reduction if closed fails **Intraoperative:** 1. **General anaesthesia** 2. **Examination under anaesthesia** - assess reducibility, stability 3. **Arthrogram** - injection of contrast into hip joint - Assess: pooling of dye (depth of acetabulum) - Assess: obstacles to reduction (pulvinar, ligamentum teres, labrum) - Assess: quality of reduction 4. **Adductor tenotomy** - percutaneous or open - Improves safe zone for abduction - Reduces pressure on femoral head (AVN prevention) 5. **Closed reduction manoeuvre:** - Flex hip to 90° - Gentle abduction and internal rotation - Ortolani manoeuvre - Feel for "clunk" of reduction 6. **Confirm reduction:** Arthrogram or fluoroscopy 7. **Assess safe zone:** Range of motion where hip stays reduced - Should be at least 30° between reduction and re-dislocation positions **Spica Cast Application:** - Human position (flexion 100°, abduction 40-50°) - Avoid extreme abduction (>60°) - AVN risk - Well-padded, waterproof - Duration: 6 weeks, then change under GA, further 6 weeks **Postoperative:** - CT scan at 24-48 hours to confirm reduction - Or MRI (no radiation) - Total spica time 12 weeks (3 months) **What if Closed Reduction Fails?** - Proceed to open reduction (medial or anterior approach) > **Consultant Tip:** Arthrogram is essential. If you can't get a concentric reduction with an adequate safe zone, proceed to open reduction at the same sitting. **Open Reduction - Indications:** - Failed closed reduction - Non-concentric reduction on arthrogram - Inadequate safe zone (<30°) - Age >18-24 months (closed reduction less likely to succeed) - Teratologic dislocation **Obstacles to Reduction:** | Structure | Description | |-----------|-------------| | **Pulvinar** | Fibrofatty tissue in acetabulum | | **Ligamentum teres** | Hypertrophied, blocking reduction | | **Transverse acetabular ligament** | May need release | | **Psoas tendon** | Hourglass constriction of capsule | | **Labrum** | Inverted, blocking entry | | **Capsule** | Contracted, hourglass deformity | **Surgical Approaches:** **Medial (Ludloff) Approach:** | Pros | Cons | |------|------| | Excellent access to obstacles | Cannot do pelvic osteotomy | | Minimal blood loss | Risk to medial femoral circumflex | | Good for age 6-18 months | Limited acetabular access | **Anterior (Smith-Petersen/Bikini) Approach:** | Pros | Cons | |------|------| | Can add pelvic osteotomy | More extensive dissection | | Good visualisation | Older children (>18 months) | | Can address acetabular dysplasia | More blood loss | **This Patient (8 months):** Medial approach reasonable. Anterior approach if pelvic osteotomy planned. **Open Reduction Technique (Medial):** 1. **Incision:** Groin crease, over adductor longus 2. **Interval:** Between adductor longus (anterior) and adductor brevis (posterior) 3. **Psoas release:** Divide psoas tendon (preserves iliacus) 4. **Capsulotomy:** T-shaped capsulotomy 5. **Clear obstacles:** Excise pulvinar, release ligamentum teres 6. **Reduce head:** Direct reduction into acetabulum 7. **Assess reduction:** Confirm concentric and stable 8. **Capsulorrhaphy:** Tighten capsule if very lax 9. **Spica cast:** As per closed reduction **Postoperative:** - CT/MRI to confirm reduction - Spica for 12 weeks - Abduction brace for further 3-6 months > **Consultant Tip:** Medial approach is elegant for young children. Beware the medial femoral circumflex artery - AVN is devastating in DDH. **Residual Acetabular Dysplasia - Assessment:** **Radiographic Measurements:** | Measurement | Normal | This Patient | |-------------|--------|--------------| | **Acetabular index** | <25° (age 3) | 38° (dysplastic) | | **Centre-edge angle** | >20° (when older) | Cannot measure yet | | **Shenton's line** | Intact | Intact (hip reduced) | | **Femoral head coverage** | >75% | ~50% | **Management Options:** **1. Observation (if mild):** - Acetabular index 25-30° - Adequate coverage on abduction - May remodel to age 8 **2. Pemberton Peri-Acetabular Osteotomy:** - Age 2-8 years - Incomplete osteotomy through ilium above acetabulum - Hinges on triradiate cartilage (must be open) - Redirects acetabulum anterolaterally - Good for acetabular dysplasia with shallow but concentric hip **3. Salter Innominate Osteotomy:** - Age 18 months - 6 years - Complete osteotomy through ilium (above acetabulum) - Redirects entire hemipelvis - Opens anterolaterally, closes posteriorly - Needs pubic symphysis mobility - Good for mild-moderate dysplasia **4. Dega Osteotomy:** - Incomplete osteotomy, hinges on triradiate - More lateral coverage than Pemberton - Good for neuromuscular conditions too **5. Triple Pelvic Osteotomy (Older Children):** - When triradiate closed or closing - Osteotomies through ilium, pubis, ischium - More complex, higher complication rate **This Patient (Age 3, AI 38°):** - Significant dysplasia requiring surgery - Triradiate cartilage open - **Pemberton or Salter osteotomy** recommended - Choice depends on surgeon preference and exact morphology **Additional Procedures:** - May need femoral shortening (if tight reduction) - May need femoral varus/rotation osteotomy (if coxa valga or anteversion) **Timing:** - Before age 4-5 for best acetabular remodelling - Don't wait for spontaneous improvement with AI >35° > **Consultant Tip:** Salter redirects the whole hemipelvis. Pemberton reshapes the acetabulum. Both need open triradiate. For severe dysplasia, Pemberton provides more correction. --- ## 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 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 --- ## 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