skip to main content

Legg-Calvé-Perthes disease — MSRA MCQ

Instant feedback + full explanation. One question, done properly.

HardHip and GroinLegg-Calvé-Perthes diseaseMSRA

A 7-year-old boy is reviewed with a 6-week history of an intermittent left-sided limp. He initially complained of left knee pain after football, but over the past 2 weeks has also described mild groin discomfort. He had a self-limiting coryzal illness shortly before the symptoms began. He is afebrile and systemically well. He can weight-bear but walks with a Trendelenburg-type limp. The knee examination is normal. Left hip internal rotation and abduction are restricted and reproduce his groin pain. There is no erythema, swelling or focal bony tenderness. Full blood count and CRP are normal. An anteroposterior pelvic radiograph performed 8 days ago was reported as normal. What is the most appropriate next step in primary care?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Arrange urgent paediatric orthopaedic assessment for suspected Perthes disease

Explanation lettering: D = shown as A · E = shown as B · B = shown as C · A = shown as D · C = shown as E

This child has a pattern concerning for Perthes disease: age 7 years, symptoms evolving over weeks, limp, referred knee pain, groin pain and restriction of hip internal rotation and abduction. A preceding viral illness may attract a diagnosis of transient synovitis, but transient synovitis should improve rapidly; persistent symptoms with restricted hip movement require reconsideration of the diagnosis. A normal early pelvic radiograph does not exclude Perthes disease, because radiographic changes can be absent early. Urgent orthopaedic assessment is therefore appropriate, with specialist-led consideration of repeat imaging or MRI. A is inappropriate because the duration and persistent mechanical restriction are not consistent with uncomplicated transient synovitis. C risks delaying diagnosis of structural hip disease. D would be appropriate with fever, systemic illness, inability to weight-bear or severe acute restriction suggesting septic arthritis, none of which is present. E is attractive because MRI can detect early disease, but suspected Perthes should be urgently referred even when initial radiographs are normal; imaging choice and timing should be coordinated through paediatric orthopaedics. ([rightdecisions.scot.nhs.uk](https://www.rightdecisions.scot.nhs.uk/nhs-tayside-refguide/surgery-and-orthopaedics/orthopaedic-and-trauma-surgery/paediatric-orthopaedics/childrens-hip-problems/perthes-disease/?organization=nhs-tayside&utm_source=openai))

Reference: NHS Tayside RefGuide: Perthe's Disease (Next review date 03/07/2027) — https://www.rightdecisions.scot.nhs.uk/nhs-tayside-refguide/surgery-and-orthopaedics/orthopaedic-and-trauma-surgery/paediatric-orthopaedics/childrens-hip-problems/perthes-disease/?organization=nhs-tayside NHSGGC: Atraumatic painful limb, paediatrics (September 2019) — https://www.clinicalguidelines.scot.nhs.uk/ggc-paediatric-guidelines/ggc-paediatric-guidelines/emergency-medicine/atraumatic-painful-limb-paediatrics-1126/ NHS: Limping in children (23 January 2025) — https://www.nhs.uk/symptoms/limp-in-children/