A 6-week-old female infant born to non-consanguineous parents presents for routine postnatal screening. On examination, there is a positive Barlow test on the left hip with a palpable clunk on adduction. The right hip is normal. Ultrasound of the left hip shows a Graf Type IIb acetabulum. What is the most appropriate next step in management?

Explanation

## Clinical Context This is a case of **developmental dysplasia of the hip (DDH)** detected early at 6 weeks of age with a positive Barlow test (hip can be dislocated) and ultrasound confirmation of borderline dysplasia (Graf Type IIb). ## Management Algorithm for DDH by Age and Severity ```mermaid flowchart TD A[DDH Suspected]:::outcome --> B{Age at Diagnosis?}:::decision B -->|< 3 months| C{Barlow/Ortolani Positive?}:::decision B -->|3-6 months| D{Ultrasound Grade?}:::decision B -->|> 6 months| E[Spica Cast or Traction]:::action C -->|Yes| F{Graf Type?}:::decision F -->|IIa, IIb| G[Pavlik Harness 12 weeks]:::action F -->|IIc, D, III, IV| H[Immediate Pavlik or Spica]:::action D -->|Mild dysplasia| I[Pavlik Harness]:::action D -->|Moderate/Severe| J[Spica Cast ± Traction]:::action G --> K[Ultrasound at 6 weeks]:::action K --> L{Improvement?}:::decision L -->|Yes| M[Continue Harness, Discharge]:::outcome L -->|No| N[Upgrade to Spica Cast]:::action ``` ## Key Management Principles **Key Point:** Pavlik harness is the **gold standard first-line treatment** for DDH diagnosed before 3 months of age with positive dynamic signs (Barlow/Ortolani) and Graf Type IIa–IIb ultrasound findings. **High-Yield:** The Pavlik harness works by maintaining the hip in **flexion (100–110°) and abduction (45–60°)**, which deepens the acetabulum and reduces the femoral head into the socket through dynamic remodeling. **Clinical Pearl:** Success rate of Pavlik harness is **95–98%** when applied before 3 months of age; this drops significantly after 6 months, necessitating spica casting or traction. ## Why Pavlik Harness at 6 Weeks? | Factor | Rationale | |--------|----------| | **Age** | < 3 months — optimal window for harness efficacy | | **Barlow positive** | Confirms dynamic instability, not fixed dislocation | | **Graf IIb** | Borderline dysplasia; harness promotes acetabular remodeling | | **Non-invasive** | Preserves hip anatomy; avoids surgery risks | | **Follow-up imaging** | Ultrasound at 6 weeks assesses response | **Tip:** Remember the **"3-month rule"** — Pavlik harness is most effective before 3 months; after 6 months, fixed deformities develop and spica casting becomes necessary. ## Expected Follow-up 1. **Ultrasound at 6 weeks** — assess acetabular remodeling (Graf grade should improve to Type I or IIa) 2. **If improved** — continue harness until hip is stable, then gradual weaning 3. **If no improvement or worsening** — upgrade to spica cast or consider traction 4. **Clinical review at each stage** — Barlow/Ortolani should become negative [cite:Tuli's Orthopedics 6e Ch 4]