Background
Lisfranc ligament attaches 2nd metatarsal to medial cuneiform
2nd metatarsal is held in mortice created by the three cuneiform bones
Injury to 2nd metatarsal often results in dislocation of the other MTs
Dorsalis pedis may be injured in severe dislocation
Lisfranc Injury = any fracture or dislocation of the tarsal-metatarsal joint
Mechanism of Injury
MVAs, falls from height, and athletic injuries
Indirect rotational forces and axial load through hyper-plantarflexed forefoot
hyperflexion/compression/abduction moment exerted on forefoot and transmitted to the TMT articulation
metatarsals displaced in dorsal/lateral direction
Clinical Features
Inability to bear weight (especially on tiptoe)
Tenderness over tarsometatarsal region
Pain with pronation and passive abduction of the midfoot
Ecchymosis of plantar section of midfoot is highly suggestive
Imaging
Obtain radiographs, which include AP, lateral, oblique, and weight bearing views.
AP: Medial margin of 2nd metatarsal base does not align with medial margin of 2nd cuneiform. Bony displacement 1mm or greater between bases of first and second metatarsals is considered unstable.
Oblique: Medial margin of 3rd metatarsal does not align with medial margin of 3rd cuneiform.
Lateral: 2nd metatarsal is higher than middle cuneiform (step-off).
If suspicion is high based on history and physical, you may want to consider obtaining further imaging in conjunction with your ortho consultants.
Treatment and Dispo
Sprains and non-displaced fractures:
Non-weightbearing splint with ortho follow up (most managed with cast x 6 weeks)
Posterior Ankle Splint
Displaced fractures:
Emergent ortho consult
When diagnosed appropriately, patients who undergo open reduction and internal fixation of fractures have superior outcomes to those with purely ligamentous injury
20% are missed on first presentation to ED, so keep this in mind the next time you see a patient with the chief complaint of foot pain!
References:
https://www.orthobullets.com/foot-and-ankle/7030/lisfranc-injury
Sherief, T et al. Lisfranc injury: How frequently does it get missed? And how can we improve? Injury: International Journal of the Care of the Injured 2007: 34; 856-860. PMID: 17214988