A Lisfranc injury (or tarsometatarsal injury) is a rare, yet extremely important, possible repercussion of trauma to the foot. Missing a Lisfranc injury may have dire consequences to the patient.

Some findings suggestive of a Lisfranc injury are:

• malalignment > 1 mm of M1-C1, M2-C2, and/or M4-Cuboid
• M1-M2 distance > 4 mm (non-weightbearing)
• M1-M2 distance > 5 mm (weightbearing)
• M1-M2 distance difference > 1 mm between feet (weightbearing)
• C1-M2 distance > 3 mm (non-weightbearing)
• C1-M2 distance > 5 mm (weightbearing)
• C1-M2 distance difference > 1 mm between feet (weightbearing)
• fleck sign - an avulsion fracture of the base of the 2^nd metatarsal or medial cuneiform which is pathognomonic of a Lisfranc injury