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Perthes disease — RACP Paediatrics MCQ

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ModerateEmergencyPerthes diseaseRACP Paediatrics

A 5-year-old presents with a 3-month history of progressive limp and hip pain. X-ray shows flattening and fragmentation of the left femoral head with surrounding lucency. There is no history of trauma. Inflammatory markers are normal. What is the most likely diagnosis?

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Correct answer: D — Perthes disease

Insidious onset hip pain with limp in a child aged 4-8 years with X-ray showing femoral head changes (flattening, fragmentation, lucency) and normal inflammatory markers is Legg-Calvé-Perthes disease (avascular necrosis of the femoral head). It is more common in boys. Management depends on age and extent of femoral head involvement, ranging from observation to surgical containment.

Reference: RCH Melbourne – 2023 – Acute Limp CPG; RACP Paediatric Curriculum – Orthopaedics