Lisfranc injury refers to disruption of the Lisfranc joint complex, the articulation between the proximal metatarsals and the distal cuneiforms and cuboid (collectively called the tarsometatarsal joint or TMT joint). The complex includes 5 articulations (TMT 1-5), the strong Lisfranc ligament (interosseous ligament between medial cuneiform and base of second metatarsal — the keystone), and supporting plantar and dorsal ligaments. The midfoot derives stability from the keystone arrangement of the second metatarsal base recessed between the medial and lateral cuneiforms.
Mechanisms include high-energy direct trauma (crush, fall from height, motor vehicle accident causing fracture-dislocation) and lower-energy indirect trauma (axial loading on a plantarflexed foot with abduction or rotation — common in football, equestrian sports, dancing, missing a step). Quenu and Kuss classification (1909) divides into: homolateral (all metatarsals displaced laterally), isolated (one or two metatarsals displaced), and divergent (1st metatarsal medially, 2nd-5th laterally). Myerson classification (1986) divides into Type A (total incongruity), Type B (partial incongruity, B1 medial, B2 lateral), and Type C (divergent, C1 partial, C2 total).
Diagnosis: clinical features include midfoot pain with weight-bearing, swelling, plantar bruising (highly suggestive), and inability to bear weight. Examination: piano key test (instability of metatarsal head with pressure), pain with passive abduction-pronation, and tenderness over the TMT joint. Imaging: weight-bearing standing AP and 30° oblique foot radiographs (more sensitive than non-weight-bearing — comparison with contralateral foot is critical). Findings: fleck sign / Hardwig sign (small avulsion between medial cuneiform and second metatarsal base) is pathognomonic; widening of space between first and second metatarsal bases more than 2 mm; loss of alignment at TMT joints; second metatarsal base medial line should align with the medial cuneiform medial line on AP, and fourth metatarsal medial line with cuboid medial line on oblique. CT is standard for surgical planning; MRI evaluates Lisfranc ligament integrity in subtle purely ligamentous cases. Treatment: anatomic reduction is critical to prevent post-traumatic arthritis. Stable, nondisplaced (less than 2 mm), and subtle injuries may be treated with non-weight-bearing cast/boot for 6-8 weeks with serial weight-bearing radiographs. Most injuries require surgical treatment: open reduction internal fixation (ORIF) with transarticular screws (3.5-4.0 mm) and plates for fracture-dislocations; primary arthrodesis (fusion of medial column TMT joints) is increasingly favored over ORIF for severe purely ligamentous injuries based on evidence of better long-term outcomes (Ly and Coetzee 2006, Henning 2009). Postoperative non-weight-bearing for 6-12 weeks. Hardware removal at 4-6 months for ORIF (some surgeons leave permanently). Untreated Lisfranc injuries lead to progressive midfoot collapse, painful arthrosis, and the need for late salvage arthrodesis.