A 14-month-old boy is brought to the orthopedic clinic with a 3-month history of limp and left groin pain. His mother reports he was born breech and was not screened for hip dysplasia in infancy. On examination, the left hip shows 20° of abduction (compared to 60° on the right), positive Trendelenburg sign, and internal rotation is limited to 10°. Plain radiographs show a shallow acetabulum (acetabular index 35°), lateral displacement of the femoral head, and delayed ossification of the femoral head epiphysis. What is the most appropriate definitive management?

Explanation

## Clinical Diagnosis & Radiographic Findings **Key Point:** This 14-month-old presents with late-diagnosed DDH (missed in infancy). The radiographic findings—shallow acetabulum (acetabular index > 30°), lateral femoral head displacement, and delayed epiphyseal ossification—confirm dysplasia with secondary changes. The positive Trendelenburg sign indicates hip instability. ## Age-Based Management Algorithm for DDH ```mermaid flowchart TD A[Diagnosed DDH]:::outcome --> B{Age at diagnosis?}:::decision B -->|< 6 months| C[Pavlik Harness]:::action B -->|6-18 months| D[Closed Reduction + Spica Cast]:::action B -->|18-24 months| E[Closed Reduction ± Adductor Tenotomy]:::action B --> |> 2 years| F[Open Reduction ± Osteotomy]:::action D --> G[Spica cast 12 weeks]:::action G --> H[Assess reduction on post-reduction imaging]:::action H --> I{Stable reduction?}:::decision I -->|Yes| J[Continue cast, then abduction orthosis]:::action I -->|No| K[Escalate to open reduction]:::urgent ``` ## Why Closed Reduction + Spica Cast at 14 Months | Age Group | Treatment | Rationale | | --- | --- | --- | | **< 6 months** | Pavlik harness | Optimal for immature hips; high remodeling potential | | **6–18 months** | Closed reduction + spica cast | Pavlik harness less effective; closed reduction achieves reduction; cast maintains position during acetabular remodeling | | **18–24 months** | Closed reduction ± adductor tenotomy | Adductors may be tight; tenotomy improves reduction stability | | **> 2 years** | Open reduction ± osteotomy | Soft tissue contractures prevent closed reduction; osteotomy corrects residual dysplasia | **High-Yield:** At 14 months, the hip is dislocated (lateral displacement confirmed on X-ray) but the child is still young enough for closed reduction to succeed. The acetabulum retains remodeling potential if the femoral head is concentrically reduced and held in position. ## Closed Reduction Technique 1. **Pre-reduction imaging:** Confirm dislocation and assess for associated femoral anteversion or acetabular dysplasia. 2. **General anesthesia:** Required for safe, gentle reduction without trauma. 3. **Reduction maneuver:** Hip flexed 100–110°, abducted 45–50°, gently internally rotated to seat the femoral head into the acetabulum. 4. **Post-reduction imaging:** X-ray or ultrasound to confirm concentric reduction. 5. **Immobilization:** Spica cast (hip flexion 100°, abduction 45–50°) for 12 weeks to allow acetabular remodeling. 6. **Follow-up:** Serial radiographs at 6 weeks, 12 weeks, and 6 months to assess acetabular development and femoral head coverage. **Clinical Pearl:** The presence of delayed femoral epiphyseal ossification (common in DDH) does not contraindicate closed reduction; it reflects the dysplastic process and will normalize with appropriate reduction and immobilization. **Key Point:** Closed reduction is successful in 85–90% of cases when performed between 6–18 months of age. Failure (persistent dysplasia or re-dislocation) occurs in ~10–15% and mandates open reduction.