UMEM Educational Pearls

Category: Orthopedics

Title: Imaging of Lisfranc Injuries

Keywords: foot fracture, radiology (PubMed Search)

Posted: 9/14/2019 by Brian Corwell, MD (Updated: 10/14/2019)
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Imaging of Lisfranc Injuries

Tarsometatarsal fracture-dislocation

Anatomy

         3 Columns of the midfoot, divided by the tarsometatarsal joints

  1. Medial
    1. First TMT joint
  2. Middle
    1. 2nd and 3rd TMT joints
  3. Lateral
    1. 4th and 5th TMT joints

The Lisfranc ligament

     - Extends from the 2nd MT to the medial cuneiform

     - Critical to structure and stabilization of the 2nd MT and the midfoot arch

 

Imaging 

Plain films: AP/lateral/oblique

Consider weight bearing view with contralateral comparison if high suspicion

CT: Can be useful to confirm abnormal plain films

MRI: not done in ED but can be used to diagnose pure ligament injuries

Below is a review of the lines of the foot which will ensure not missing this diagnosis. May be helpful to review with sample imaging.

Plain films findings: https://prod-images.static.radiopaedia.org/images/49189279/86408d5bae08ab80ae9ef377337ab7_big_gallery.jpeg

 

On AP view:

  1. Discontinuity of a line drawn from the medial part of 2nd MT to the medial side of the 2nd cuneiform
  2. Widening of the interval between the 1st and 2nd ray
  3. Bony fragment in 1st MT space (fleck sign) – Lisfranc ligament avulsion

On Lateral view:

  1. Dorsal displacement of the proximal 1st or 2nd MT (may be subtle)

On the Oblique view:

  1. Discontinuity of a line drawn from the medial border of the 3rd cuneiform with the medial border of the 3rd MT
  2. Discontinuity of a line drawn from the medial side of the 4th MT with the medial side of the cuboid 

Remember that the lateral margin of the 5th MT can project lateral to the cuboid (up to 3 mm)

 

Lines drawn on 2 view foot for review

https://radiopaedia.org/cases/lisfranc-ligament-normal-alignment

 

 

 

References

https://radiopaedia.org

Orthobullets.org