A 12-year-old obese boy presents with right hip pain and limp for 4 weeks. He walks with an antalgic gait, and internal rotation of the hip is restricted and painful. On 'log roll' testing, the hip automatically externally rotates. X-ray shows posterior and inferior displacement of the femoral epiphysis on the right. This is a slipped capital femoral epiphysis (SCFE). Which imaging view is MOST sensitive for detecting early SCFE?

• A AP pelvis view alone
• B Frog-leg lateral (Lauenstein) view of the hip ✓
• C MRI of the pelvis with gadolinium
• D Ultrasound of the hip for joint effusion

Explanation

The frog-leg lateral (Lauenstein) view is most sensitive for early SCFE because the slip occurs posteriorly and inferiorly — a posterior slip may appear normal on AP view (where only medial displacement is visible as loss of Klein's line intersection) but is clearly seen as posterior epiphyseal displacement on the frog-leg lateral. Both AP and frog-leg lateral should be obtained; the AP shows Klein's line (Trethowan's sign) disruption for medial slips, but lateral view catches isolated posterior slips. MRI is reserved for pre-slip (physeal widening without displacement) or avascular necrosis assessment, not for initial diagnosis.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.