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Suspected acute Lisfranc injury — MSRA MCQ

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HardAnkle and FootSuspected acute Lisfranc injuryMSRA

A 15-year-old boy is assessed in a minor injuries unit 5 hours after a rugby injury. Another player landed on the back of his right heel while his forefoot was plantar-flexed. He was initially able to take four steps but now has increasing pain on push-off. There is marked dorsal midfoot swelling, plantar bruising and maximal tenderness over the first and second tarsometatarsal joints. Passive forefoot abduction with pronation produces severe pain. There is no tenderness at the navicular, base of the fifth metatarsal, malleoli or Achilles tendon. Neurovascular examination is normal. Standard non-weight-bearing anteroposterior, oblique and lateral foot radiographs show no definite fracture or malalignment. What is the most appropriate management today?

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

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Correct answer: D — Discuss immediately with the on-call orthopaedic team and arrange urgent CT assessment of the Lisfranc joints, keeping him non-weight-bearing pending their plan

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

This is a suspected Lisfranc injury despite apparently normal initial radiographs. The important linked features are the plantar-flexed loading mechanism, marked midfoot swelling with plantar bruising, focal first/second tarsometatarsal tenderness, and pain provoked by forefoot abduction-pronation stress. These indicate possible tarsometatarsal ligament disruption and instability rather than an uncomplicated midfoot sprain. His ability to take four steps does not safely exclude this diagnosis. Ottawa foot-rule landmarks are absent, but the rules are a fracture-imaging aid and should not override a specific clinical pattern suggesting Lisfranc injury. Non-weight-bearing radiographs may also fail to demonstrate subtle instability. In the applicable NHS paediatric orthopaedic guidance, significant midfoot swelling and plantar haematoma should prompt suspicion of Lisfranc injury and urgent CT assessment. B, C and E risk delayed recognition of an unstable injury. D is initially attractive because MRI can define ligament injury, but urgent orthopaedic discussion and CT are the specified immediate pathway here; outpatient MRI should not substitute for same-day assessment. Non-weight-bearing protection is prudent while instability is being assessed and the orthopaedic plan is determined.

Reference: RHCYP Orthopaedics – Information for FYs (August 2024) — https://www.rightdecisions.scot.nhs.uk/media/a02jttf4/fy-orthopaedic-induction-2024_aug-pdf.pdf Acute Lisfranc injury management (2024) — https://pubmed.ncbi.nlm.nih.gov/39615511/ A painful foot: Lisfranc fracture-dislocations (2016) — https://www.bmj.com/content/352/bmj.i882