High-Yield Summary
- Lisfranc injuries involve disruption of the tarsometatarsal (TMT) joint complex, with subtle presentations requiring high clinical suspicion and weight-bearing radiographs for diagnosis.
- The stability of the Lisfranc ligament complex dictates management; displacement >2 mm or joint incongruity mandates operative fixation.
- Open reduction and internal fixation (ORIF) remains the gold standard for unstable injuries, with emerging evidence supporting primary arthrodesis in purely ligamentous injuries.
- Accurate reduction of the TMT joint alignment is critical to prevent post-traumatic arthritis and chronic instability.
- Postoperative protocols emphasize protected weight-bearing and close radiographic monitoring to detect loss of reduction.
Clinical Fundamentals
Relevant Anatomy
The Lisfranc joint complex comprises the articulation between the first, second, and third metatarsals and the three cuneiforms, plus the cuboid and fourth/fifth metatarsals. The Lisfranc ligament is a strong oblique interosseous ligament connecting the medial cuneiform to the base of the second metatarsal, providing primary stability. The second metatarsal base acts as a keystone, locked into a mortise formed by the cuneiforms, conferring inherent bony stability.
Biomechanics
The TMT joint complex transmits axial and rotational forces during gait. The second metatarsal base’s mortise configuration resists displacement, but ligamentous disruption compromises this stability, leading to abnormal joint mechanics and altered load distribution. Even minimal diastasis (>2 mm) can cause significant functional impairment.
Epidemiology
Lisfranc injuries are uncommon but often underdiagnosed, accounting for approximately 0.2% of fractures. They occur in high-energy trauma (motor vehicle collisions, falls) and low-energy mechanisms (sports injuries, twisting). Delayed diagnosis correlates with worse outcomes.
Classification & Diagnosis
| Classification System | Description | Clinical Relevance |
|---|---|---|
| Hardcastle Classification | Type A: Total incongruity; Type B: Partial incongruity (medial or lateral displacement); Type C: Divergent displacement | Guides surgical approach and fixation strategy based on displacement pattern |
| Myerson Modification | Adds subtypes based on direction of displacement and comminution | Refines treatment planning, especially for partial injuries |
| Nunley and Vertullo | Graded by weight-bearing radiograph findings and diastasis | Helps decide operative vs. non-operative management |
Diagnostic Pearls
- Obtain weight-bearing AP, lateral, and oblique foot radiographs; non-weight-bearing films often miss subtle diastasis.
- Look for >2 mm diastasis between the first and second metatarsal bases or malalignment of the medial cuneiform and second metatarsal.
- CT scan is invaluable for assessing comminution and subtle fractures; MRI can delineate ligamentous injury when radiographs are inconclusive.
- Beware of missed injuries in polytrauma or when initial swelling obscures clinical signs.
Decision-Making Algorithm
| Criteria | Non-Operative Management | Operative Management |
|---|---|---|
| Displacement <2 mm, stable on weight-bearing | Indicated | Not indicated |
| Displacement >2 mm or joint incongruity | Contraindicated | Indicated |
| Purely ligamentous injury with instability | Controversial; often operative | Primary arthrodesis or ORIF |
| Comminuted fractures or divergent displacement | Not indicated | ORIF with possible fusion |
Rationale for Surgical Approach and Implant Choice
- ORIF with screws or dorsal plates aims to restore anatomic alignment and maintain reduction.
- Primary arthrodesis is favored in purely ligamentous injuries or chronic instability to prevent late arthritis.
- Screw fixation across the second TMT joint is biomechanically superior; dorsal plates may be used for comminuted fractures.
- Minimally invasive techniques are emerging but require careful patient selection.
Surgical Mastery & Pearls
Step-by-Step Conceptual Overview
- Exposure: Dorsal longitudinal incision centered over the second TMT joint; protect dorsal neurovascular structures.
- Reduction: Achieve anatomic reduction of the second metatarsal base into the cuneiform mortise under direct visualization and fluoroscopy.
- Temporary Fixation: Use K-wires to maintain reduction before definitive fixation.
- Definitive Fixation: Insert 3.5 mm cortical screws across the Lisfranc joint, typically from medial cuneiform to second metatarsal base; supplement with screws or plates for adjacent joints as needed.
- Assessment: Confirm reduction and hardware placement with fluoroscopy in multiple planes.
- Closure: Layered closure with attention to soft tissue integrity.
Intraoperative Red Flags
- Persistent diastasis despite reduction attempts suggests soft tissue interposition or missed fracture fragment.
- Overcompression of the joint can cause iatrogenic cartilage damage; maintain anatomic spacing.
- Hardware prominence dorsally can cause irritation; countersink screws when possible.
- Avoid excessive stripping of dorsal soft tissues to preserve blood supply.
Evidence-Based Synthesis
Recent randomized controlled trials and meta-analyses have refined the management paradigm for Lisfranc injuries. The landmark study by Deol et al. demonstrated superior functional outcomes and lower reoperation rates with primary arthrodesis compared to ORIF in purely ligamentous injuries. Conversely, fractures with bony involvement benefit from ORIF to preserve joint motion.
Biomechanical studies confirm that screw fixation across the second TMT joint provides superior stability compared to K-wires or dorsal plates alone. However, controversy persists regarding the optimal implant choice in comminuted injuries.
Long-term cohort studies emphasize that anatomic reduction is the strongest predictor of good outcomes, regardless of fixation method. Non-operative management remains appropriate only for stable, non-displaced injuries, with vigilant follow-up.
Master Class Pro-Tip
Mastery in Lisfranc fixation hinges on appreciating the second metatarsal base as the keystone of the midfoot. Prioritize anatomic reduction of this joint before addressing adjacent articulations. Use intraoperative fluoroscopy judiciously to confirm alignment in multiple planes, and do not hesitate to extend fixation to adjacent joints if instability persists. Recognize that subtle malalignment, even by 1-2 mm, predisposes to debilitating post-traumatic arthritis. Finally, tailor your fixation strategy to the injury pattern-primary arthrodesis for ligamentous injuries, ORIF for fractures-balancing joint preservation with long-term stability.
