First and second year — the floor first, then every step
Check two alignments on every foot radiograph — the medial second metatarsal against the middle cuneiform, the medial fourth against the cuboid — and the gap between the first and second metatarsal bases. The injury that is missed is subtle and ligamentous.
Orient first
The Lisfranc ligament runs from the medial cuneiform to the base of the second metatarsal; there is no ligament between the first and second metatarsal bases, which is why this is the weak point.
Up to a substantial proportion are missed on the first radiograph, especially purely ligamentous injuries seen only on weight-bearing views.
A FLECK SIGN — a small avulsed fragment between the first and second metatarsal bases — is an avulsion of the Lisfranc ligament.
Acquire the study
AP, 30° oblique and lateral of the foot; WEIGHT-BEARING AP views (both feet) when the patient can stand.
The manoeuvre
AP view: the MEDIAL border of the second metatarsal base must line up with the medial border of the MIDDLE CUNEIFORM.
Oblique view: the medial border of the FOURTH metatarsal base lines up with the medial border of the CUBOID; the third with the lateral cuneiform.
Measure the gap between the first and second metatarsal bases (and the medial cuneiform–second metatarsal gap) against the other foot.
Fleck sign between the first and second metatarsal bases.
Lateral view: dorsal step of the metatarsal bases relative to the cuneiforms.
What confirms it
Malalignment of the second metatarsal with the middle cuneiform, diastasis compared with the other foot, a fleck sign, or ligament disruption on MRI.
What licenses you to exclude it
A non-weight-bearing radiograph cannot exclude a ligamentous Lisfranc injury.
The classic misread
Calling a non-weight-bearing film normal in a patient with midfoot tenderness and plantar ecchymosis — request weight-bearing views or CT/MRI.
Reporting the injury
Classification to use
Myerson (homolateral, isolated/partial, divergent) or Nunley–Vertullo for subtle athletic injuries — descriptive reporting of alignment and diastasis is what is acted on.
Measurements — and how to take them
Medial cuneiform–second metatarsal and first–second metatarsal base distances in mm, against the contralateral foot (a side-to-side difference of about 2 mm or more is commonly considered abnormal — verify).
What to report
Alignment at each tarsometatarsal joint, diastasis in mm (with the contralateral comparison), fleck sign, associated fractures, weight-bearing status of the study.
How to report it
X-ray: "On weight-bearing AP views there is 3 mm diastasis between the medial cuneiform and the base of the second metatarsal compared with 1 mm on the left, with a small fleck fragment in the first intermetatarsal space — Lisfranc injury."
What not to report
Do not report a normal midfoot on non-weight-bearing films without saying weight-bearing views are needed when clinically suspected.
Associated injuries to look for
Cuboid compression fracture, metatarsal base and neck fractures, compartment syndrome of the foot (clinical).
What changes management
Any diastasis or malalignment on weight-bearing imaging — operative fixation; a stable sprain without diastasis — conservative.
Reference values
Each value carries the caveat that keeps it from being misused. Normal limits and diagnostic criteria are kept apart on purpose: a disease cut-off read as a normal range is the more dangerous mistake.
Diagnostic criteria
Tarsometatarsal joints · Lisfranc alignment and the C1–M2 interval
the medial border of the second metatarsal base aligns with the medial border of the middle cuneiform on the AP view; a gap over approximately 2 mm between the medial cuneiform and the second metatarsal base suggests Lisfranc injury
⚠️ WEIGHT-BEARING VIEWS ARE PART OF THE TEST — a non-weight-bearing film can look normal in a purely ligamentous injury. The "fleck sign" (avulsion in the C1–M2 interval) is diagnostic at any interval. CT resolves the equivocal film.
X-ray · CT
See it on real cases
Direct links to Radiopaedia — the reference article and worked cases with their images. Each opens on Radiopaedia.