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Perthes Disease Imaging — RACP Paediatrics MCQ

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ModerateRheumatologyPerthes Disease ImagingRACP Paediatrics

A 6-year-old presents with a limp and knee pain. On examination, he has limited internal rotation and abduction of the right hip. X-ray shows increased density (sclerosis) of the right femoral head with early fragmentation. What imaging modality best assesses the extent of femoral head involvement?

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Correct answer: C — MRI hip

MRI is the most sensitive imaging for Perthes disease (Legg-Calvé-Perthes), demonstrating the extent of epiphyseal necrosis, containment of the femoral head, and early changes before radiographic changes appear. It guides prognostic classification (Herring lateral pillar classification) and management decisions.

Reference: RCH Melbourne – 2024 – Clinical Practice Guidelines: Perthes Disease