Which of the following is the most sensitive clinical sign for detecting developmental dysplasia of hip (DDH) in a 3-month-old infant?

Explanation

## Clinical Examination for DDH **Key Point:** The Ortolani test is the most sensitive clinical sign for detecting DDH in infants under 3 months of age, with sensitivity approaching 60–80% when performed correctly. ### Ortolani Test (Reduction Test) - **Mechanism:** The examiner abducts the flexed hip while applying gentle anterior pressure to the greater trochanter. - **Positive finding:** A palpable clunk or click as the femoral head reduces into the acetabulum. - **Sensitivity:** Highest in infants < 3 months; decreases after 3 months as capsular laxity resolves. - **Specificity:** Lower in first 2 weeks of life due to physiological laxity. ### Barlow Test (Provocation Test) - **Mechanism:** The examiner adducts the flexed hip while applying posterior pressure to the femoral head. - **Positive finding:** A palpable clunk as the femoral head dislocates posteriorly. - **Sensitivity:** Slightly lower than Ortolani in detecting established DDH. - **Use:** Best for detecting instability rather than fixed dislocation. ### Comparison Table | Test | Age Group | Mechanism | Finding | Sensitivity | | --- | --- | --- | --- | --- | | **Ortolani** | < 3 months | Abduction + anterior pressure | Clunk (reduction) | 60–80% | | **Barlow** | < 3 months | Adduction + posterior pressure | Clunk (dislocation) | 50–70% | | **Trendelenburg** | > 3 years | Single-leg stance | Pelvic drop | Late sign | | **Galeazzi** | 2–6 months | Knee height comparison | Knee height discrepancy | Moderate | **High-Yield:** In clinical practice, both Ortolani and Barlow are performed together as a screening pair. Ortolani is more sensitive for reduction; Barlow is more specific for instability. **Clinical Pearl:** After 3 months of age, the hip capsule tightens and these tests become less reliable. Galeazzi sign (asymmetry of knee heights with hips flexed) becomes more useful in infants 2–6 months old. Trendelenburg sign appears only when the child begins weight-bearing (> 3 years). **Warning:** A negative Ortolani and Barlow test does NOT exclude DDH—ultrasound screening is still recommended in high-risk populations (family history, breech presentation, female gender).