A 3-month-old girl born to a 28-year-old primigravida is brought to the pediatric orthopedic clinic by her mother for routine developmental screening. The child was delivered vaginally after an uncomplicated pregnancy. On examination, the infant is in breech position on the examination table. The left hip shows a positive Barlow test with a palpable clunk on adduction, and the Ortolani test reproduces the clunk on abduction. The right hip appears clinically normal. Ultrasound of the hip (Graf classification) shows the left hip with an alpha angle of 52° and beta angle of 65°. What is the most appropriate next step in management?

Explanation

## Clinical Diagnosis: Developmental Dysplasia of Hip (DDH) — Graf Type IIb ### Interpretation of Clinical Findings **Key Point:** The positive Barlow and Ortolani tests with an audible clunk in a 3-month-old infant are pathognomonic for DDH with hip instability. The breech presentation is a significant risk factor. **High-Yield:** Graf ultrasound classification: - **Type I (normal):** α ≥ 60°, β < 55° - **Type IIa (physiologic immaturity):** α 50–59°, β 55–77° - **Type IIb (dysplasia):** α 50–59°, β > 77° (or α < 50°, β < 77°) - **Type III/IV:** Dislocated hip This infant's α = 52° and β = 65° falls into **Type IIb** (dysplasia with instability). ### Management Algorithm for Type IIb DDH ```mermaid flowchart TD A[DDH Type IIb diagnosed]:::outcome --> B{Age at diagnosis?}:::decision B -->|< 6 months| C[Pavlik harness]:::action B -->|6-18 months| D[Consider harness or abduction orthosis]:::action B -->|> 18 months| E[Closed/open reduction + spica]:::action C --> F[Weekly clinical + ultrasound follow-up]:::action F --> G{Hip reduction achieved?}:::decision G -->|Yes| H[Continue harness 12 weeks total]:::action G -->|No| I[Escalate to closed/open reduction]:::action H --> J[Wean gradually, long-term surveillance]:::outcome ``` ### Pavlik Harness: Gold Standard at This Age **Clinical Pearl:** The Pavlik harness is the first-line treatment for DDH diagnosed before 6 months of age because: 1. Hip is still highly malleable; cartilaginous femoral head remodels rapidly 2. Success rate 90–95% when applied correctly 3. Non-invasive, allows normal hip motion in flexion and abduction 4. Avoids operative morbidity and avascular necrosis risk **Key Point:** Harness must maintain hip in flexion (90–110°) and abduction (45–60°) — the "position of safety." ### Monitoring Protocol - **Weekly clinical assessment:** Check for skin irritation, assess abduction/flexion, confirm proper fit - **Ultrasound at 2, 4, and 12 weeks:** Confirm progressive reduction and remodeling - **Duration:** 12 weeks continuous wear if reduction achieved by week 2–4 - **Weaning:** Gradual reduction over 2–4 weeks after 12 weeks **High-Yield:** If reduction not achieved by 4–6 weeks, or if harness intolerance occurs → escalate to closed reduction under anesthesia ± spica cast. [cite:Tuli's Orthopedics 5e Ch 10]