What is a Lisfranc injury?

Lisfranc Injury of the Foot

A Lisfranc injury is a disruption of the tarsometatarsal (TMT) joint complex in the midfoot, involving damage to the Lisfranc ligamentous complex and/or fractures of associated bones, which requires prompt diagnosis and appropriate management to prevent chronic disability. 1

Anatomy and Mechanism

• The Lisfranc joint complex consists of the articulations between the tarsal bones and the bases of the metatarsals
• The Lisfranc ligament connects the medial cuneiform to the base of the second metatarsal
• Injury mechanisms include:
  • High-energy trauma (motor vehicle accidents, falls from height)
  • Low-energy trauma (sports injuries, especially twisting injuries with a fixed forefoot)
  • Hyperflexion injuries to the midfoot 2

Clinical Presentation

• Midfoot pain, swelling, and ecchymosis
• Pain with weight-bearing
• Plantar ecchymosis (highly suggestive of Lisfranc injury)
• Widening between the first and second metatarsals
• Pain with pronation and abduction of the forefoot while stabilizing the hindfoot 3

Diagnostic Approach

Initial Imaging

1. Standard radiographs (three-view series of the foot) are the first-line imaging study 1

   • Weight-bearing views when possible (critical for detecting subtle instability)
   • Look for:
     • Widening between the 1st and 2nd metatarsal bases (>2mm)
     • Fleck sign (small avulsion fracture)
     • Disruption of normal alignment between metatarsals and tarsals

2. When radiographs are negative but clinical suspicion remains high:

   • CT scan: Superior for detecting bony injuries, non-displaced fractures, and planning surgery 2
   • MRI: Best for evaluating the Lisfranc ligamentous complex and associated soft tissue injuries 2, 1
   • Weight-bearing CT when available: Provides functional assessment of instability

Classification

Lisfranc injuries range from purely ligamentous injuries to complex fracture-dislocations:

• Purely ligamentous - Disruption of ligaments without fractures
• Bony - Fractures of metatarsal bases (especially 2nd metatarsal base, present in ~50% of cases) 4
• Combined - Both ligamentous and bony injuries

Management Algorithm

1. Stable Injuries (no displacement on weight-bearing radiographs)

• Non-weight bearing cast for 6 weeks
• Followed by graduated weight bearing in a protective boot
• Regular clinical and radiographic follow-up to ensure proper alignment 1, 5

2. Unstable Injuries

• Purely ligamentous unstable injuries:

  • Primary arthrodesis shows better functional outcomes, increased cost-effectiveness, and reduced rates of return to theater 5, 6

• Bony unstable injuries:

  • Open reduction and internal fixation (ORIF) is generally preferred
  • Fixation options include screws, plates, or K-wires
  • Dorsal bridge plates are emerging as the preferred fixation method 6

3. High-Energy Complex Injuries

• CT scan is essential for preoperative planning 2, 1
• May require staged procedures if significant soft tissue injury
• Higher risk of complications including compartment syndrome

Complications

• Post-traumatic arthritis (occurs in up to 45% of cases) 4
• Chronic pain and disability
• Midfoot instability and arch collapse
• Delayed or missed diagnosis (occurs in up to 20% of cases) 7

Pitfalls to Avoid

• Delayed diagnosis - Almost 20% of Lisfranc injuries are initially missed 7
• Inadequate imaging - Standard radiographs may appear normal; weight-bearing views or advanced imaging are often necessary
• Premature weight-bearing - Can lead to chronic instability and arthritis
• Inadequate reduction - Even small amounts of residual displacement can lead to significant disability 1

Follow-up

• Regular clinical and radiographic follow-up is essential to ensure proper alignment and healing
• Long-term monitoring for development of post-traumatic arthritis
• Functional rehabilitation once healing permits

Lisfranc injuries represent a spectrum of midfoot injuries that require careful evaluation and appropriate management to optimize outcomes. Early diagnosis and proper treatment are critical to prevent long-term disability and chronic pain.