# 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 --- ## 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 --- ## Questions & Model Answers **Definition of Pavlik Failure:** Failure to achieve stable, concentric reduction after 3-4 weeks of full-time Pavlik harness use in an appropriately fitted infant. **Criteria for Pavlik Failure:** | Criteria | Description | |----------|-------------| | **Persistent dislocation** | Hip remains dislocated on ultrasound | | **Failure to reduce** | Ortolani remains negative | | **Worsening instability** | Hip becomes more unstable | | **Time frame** | No improvement after 3-4 weeks | **Causes of Pavlik Failure:** | Category | Causes | |----------|--------| | **Patient factors** | Severe dysplasia (Graf III/IV), bilateral DDH, teratologic DDH, neuromuscular conditions | | **Technical factors** | Improper fit, incorrect strap tension, non-compliance | | **Anatomical factors** | Inverted limbus, hypertrophied ligamentum teres, psoas tendon interposition, pulvinar hypertrophy | | **Timing factors** | Late presentation (>6 months), delayed initiation of treatment | **This Patient's Failure Factors:** - Graf Type IV (severe dysplasia) - Irreducible (Ortolani negative) - 6 weeks of treatment without improvement - Likely anatomical obstruction to reduction **Importance of Early Recognition:** - Continuing Pavlik in irreducible hip causes Pavlik harness disease - Damage to posterior acetabulum from pressure of dislocated head - Must discontinue if no reduction by 3-4 weeks > **Consultant Tip:** If ultrasound shows no improvement by 3-4 weeks, STOP the Pavlik. Continuing risks Pavlik harness disease. **Graf Classification:** | Type | Alpha Angle | Beta Angle | Description | Treatment | |------|-------------|------------|-------------|-----------| | **I** | >60° | <55° | Normal, mature hip | None | | **IIa** | 50-60° | 55-77° | Physiologically immature (<3 months) | Observe | | **IIb** | 50-60° | 55-77° | Delayed ossification (>3 months) | Harness | | **IIc** | 43-49° | <77° | Critically unstable | Harness | | **D** | 43-49° | >77° | Decentered, everted labrum | Harness | | **III** | <43° | >77° | Dislocated, cartilage roof deformed | Harness/Reduction | | **IV** | <43° | >77° | Dislocated, inverted labrum | Reduction required | **This Patient: Graf Type IV (Left Hip)** - Alpha angle 38° (<43°) - severely dysplastic - Beta angle 85° (>77°) - labrum everted/inverted - Femoral head dislocated - Labral inversion blocks reduction **Key Ultrasound Landmarks:** | Structure | Normal Finding | |-----------|----------------| | **Iliac bone** | Straight line to acetabular roof | | **Labrum** | Triangular, covers femoral head | | **Femoral head** | Centered, covered by >50% of acetabulum | | **Alpha angle** | >60° (bony coverage) | | **Beta angle** | <55° (cartilaginous coverage) | **When to Use Ultrasound vs X-ray:** | Age | Preferred Imaging | Rationale | |-----|-------------------|-----------| | 0-4 months | Ultrasound | Femoral head not ossified | | 4-6 months | Both useful | Ossification variable | | >6 months | X-ray | Femoral head ossified | > **Consultant Tip:** Alpha angle >60° = normal. Alpha angle <43° with labral abnormality = significant DDH requiring intervention. **Management Algorithm After Pavlik Failure:** | Age | First-line Option | Second-line | |-----|------------------|-------------| | **<6 months** | Fixed abduction brace (Rhino) | Closed reduction + spica | | **6-18 months** | Closed reduction + spica | Open reduction if fails | | **18-24 months** | Open reduction ± osteotomy | Primary open reduction | | **>24 months** | Open reduction + pelvic ± femoral osteotomy | Complex reconstruction | **This Patient (5 months, Pavlik failure):** **Recommended Pathway:** 1. **Discontinue Pavlik immediately** 2. **Trial fixed abduction brace (Rhino/Craig harness)** 3. **If still dislocated in 2-3 weeks → Arthrogram + closed reduction** 4. **If closed reduction fails → Open reduction** **Closed Reduction Technique:** | Step | Detail | |------|--------| | **Arthrogram** | Assess reducibility, identify blocks | | **Adductor tenotomy** | Percutaneous, reduces pressure on femoral head | | **Gentle reduction** | Traction, abduction, gentle pressure | | **Safe zone assessment** | Document stable ROM before impingement | | **Spica cast** | Human position (100° flexion, 40° abduction) | **Indications for Open Reduction:** | Indication | Rationale | |------------|-----------| | Failed closed reduction | Anatomical block to reduction | | Narrow safe zone | Risk of AVN with closed reduction | | Inverted limbus on arthrogram | Mechanical obstruction | | Age >18 months | Higher closed reduction failure | > **Consultant Tip:** Age <6 months and Pavlik failure = try fixed abduction brace first. If still dislocated, proceed to closed reduction under anaesthesia. **Indication for Open Reduction:** - Failed closed reduction - Anatomical block identified (inverted limbus) - Narrow safe zone (<30° of stable abduction) **Surgical Approach:** | Approach | Age/Indication | Advantages | |----------|----------------|------------| | **Medial (Ludloff/Ferguson)** | <12-18 months, no capsulorrhaphy needed | Less invasive, cosmetic | | **Anterior (Smith-Petersen/Bikini)** | >12-18 months, capsulorrhaphy required | Better exposure, can plicate capsule | **Anterior Approach Technique (for this patient if closed reduction fails):** | Step | Detail | |------|--------| | **Incision** | Bikini line or Smith-Petersen | | **Internervous plane** | Sartorius (femoral n.) and TFL (superior gluteal n.) | | **Identify and protect** | Lateral femoral cutaneous nerve | | **Release iliopsoas** | At lesser trochanter (addresses obstruction) | | **Open capsule** | T-shaped capsulotomy | | **Clear obstructions** | Ligamentum teres, pulvinar, transverse acetabular ligament | | **Reduce head** | Gentle, concentrically into acetabulum | | **Assess stability** | Document safe zone | | **Capsulorrhaphy** | Tighten redundant capsule | | **Spica cast** | Human position | **Structures Blocking Reduction:** | Structure | Intervention | |-----------|--------------| | **Inverted limbus** | Excise or evert (controversial) | | **Hypertrophied ligamentum teres** | Divide | | **Hypertrophied pulvinar** | Excise | | **Tight iliopsoas** | Release | | **Transverse acetabular ligament** | Divide if blocking | | **Hourglass capsule** | Release constriction | > **Consultant Tip:** Medial approach for younger infants (<12 months), anterior approach for older children or when capsulorrhaphy needed. **Residual/Recurrent Dysplasia:** After successful reduction, some hips develop residual dysplasia requiring secondary procedures. **Assessment:** | Measurement | Normal | Abnormal | |-------------|--------|----------| | **Acetabular index** | <25° by age 2 | >30° at age 2+ | | **CEA (older child)** | >25° | <20° | | **Migration percentage** | <25% | >33% | | **Shenton's line** | Intact | Broken | **This Patient: AI 35° at age 2 = significant residual dysplasia** **Pelvic Osteotomy Options:** | Osteotomy | Age Range | Mechanism | Indication | |-----------|-----------|-----------|------------| | **Salter innominate** | 18 months - 6 years | Redirectional | Anterolateral deficiency, hip reduced | | **Pemberton** | 18 months - 8 years | Reshaping (acetabuloplasty) | Larger acetabulum needed | | **Dega** | 18 months - 8 years | Reshaping | Posterior deficiency, NM conditions | | **Steel (triple)** | 8-15 years | Redirectional | Older child, preserves pelvic shape | | **Ganz (PAO)** | Skeletal maturity | Redirectional | Adolescent/adult | **Salter Innominate Osteotomy (Most Common):** | Principle | Detail | |-----------|--------| | **Mechanism** | Rotates acetabulum anterolaterally on pubic symphysis | | **Effect** | Improves anterior and lateral coverage | | **Graft** | Iliac crest wedge | | **Limitation** | Limited correction (15-20°), requires reduced hip | **Femoral Osteotomy:** | Indication | Procedure | |------------|-----------| | Excessive anteversion | Derotation osteotomy | | Coxa valga | Varus osteotomy | | Combined deformity | Combined derotation + varus | **Combined Procedures:** - Salter + femoral varus derotation osteotomy common - One-stage if hip concentrically reduced - Sequential if open reduction needed first > **Consultant Tip:** Salter works by redirection (rotating acetabulum). Pemberton/Dega reshape the acetabulum. Choose based on deficiency pattern. **Complications of Treatment:** | Complication | Cause | Prevention | |--------------|-------|------------| | **AVN** | Excessive abduction, pressure on vessels | Safe zone assessment, human position casting | | **Redislocation** | Inadequate reduction, poor compliance | Confirm reduction, proper spica technique | | **Residual dysplasia** | Inadequate remodelling | Close follow-up, secondary procedures | | **Stiffness** | Prolonged immobilisation | Early protected ROM | | **Growth disturbance** | AVN affecting physis | Avoid excessive abduction | | **Pavlik harness disease** | Continued Pavlik in irreducible hip | Early recognition of failure | **AVN Classification (Kalamchi-MacEwen):** | Type | Pattern | Prognosis | |------|---------|-----------| | **I** | Delayed ossification only | Good | | **II** | Lateral physeal damage | Coxa valga | | **III** | Central physeal damage | Short neck | | **IV** | Total head involvement | Poor, severe deformity | **AVN Prevention:** - Avoid abduction >60° - Use "human position" in spica (not frog leg) - Monitor with MRI if concern - Safe zone >30° before casting **Long-term Prognosis:** | Factor | Good Prognosis | Poor Prognosis | |--------|----------------|----------------| | **Age at reduction** | <6 months | >18 months | | **Reduction type** | Closed, stable | Open, required osteotomy | | **Concentric reduction** | Achieved | Residual subluxation | | **AVN** | None | Present | | **Residual dysplasia** | None | Persistent AI elevation | **Follow-up Protocol:** | Age | Assessment | |-----|------------| | **Every 3 months** | Clinical exam, X-ray until age 2 | | **Every 6 months** | Until skeletal maturity | | **Adolescence** | Assess for residual dysplasia, consider PAO | | **Adulthood** | OA surveillance | **Expected Outcomes:** - Early diagnosed and treated (0-6 months): 95%+ normal hips - Pavlik failure requiring surgery: 85-90% good outcomes - Late diagnosis (>18 months): Higher rates of AVN, residual dysplasia, early OA > **Consultant Tip:** AVN is the most feared complication. It is iatrogenic - caused by treatment, not the DDH itself. Excessive abduction is the enemy. --- ## 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:** | Risk Factor | Significance | |-------------|--------------| | Graf Type III/IV | Severe dysplasia | | Bilateral DDH | Higher failure rate | | Late presentation | Soft tissue contracture | | Male sex | Less common but more severe | | Teratologic DDH | Associated with syndromes | ### 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 --- ## 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 --- **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. --- **Q: "What is the difference between Salter and Pemberton osteotomies?"** | Feature | Salter | Pemberton | |---------|--------|-----------| | **Mechanism** | Redirectional | Reshaping (acetabuloplasty) | | **Hinge** | Pubic symphysis | Triradiate cartilage | | **Correction** | ~15-20° | Variable | | **Age range** | 18 months - 6 years | 18 months - 8 years | | **Triradiate cartilage** | Must be open | Must be open | | **Effect** | Rotates entire hemipelvis | Changes acetabular shape | --- **Q: "What radiographic measurements do you use in DDH?"** | Measurement | Definition | Normal | |-------------|------------|--------| | **Acetabular index** | Angle of acetabular roof | <30° (age-dependent) | | **CEA (Wiberg)** | Centre-edge angle | >25° | | **Shenton's line** | Arc from femoral neck to obturator | Smooth, intact | | **Perkin's line** | Vertical from lateral acetabulum | Femoral head medial | | **Hilgenreiner's line** | Horizontal through triradiate | Reference line | --- ## Related Topics - DDH Screening and Diagnosis - Pavlik Harness Application - Open Reduction of DDH - Pelvic Osteotomies in DDH - AVN of Femoral Head - Residual Hip Dysplasia