Lisfranc Injuries

Lisfranc injuries involve disruption of the tarsometatarsal (TMT) joint complex of the midfoot. These injuries range from subtle ligament sprains to severe fracture-dislocations. Accurate diagnosis is critical because missed Lisfranc injuries can lead to chronic pain, midfoot instability, and post-traumatic arthritis.

The Lisfranc joint complex plays an essential role in maintaining the structural integrity of the medial longitudinal arch of the foot. Disruption of this joint complex leads to significant functional impairment and difficulty with weight bearing.

Lisfranc injuries are often misdiagnosed, particularly when the injury is purely ligamentous and radiographic findings are subtle. Early recognition and appropriate treatment are therefore essential to restore midfoot stability and prevent long-term disability.

The Lisfranc joint complex consists of the articulation between the metatarsal bases and the tarsal bones of the midfoot.

• First metatarsal articulates with medial cuneiform
• Second metatarsal articulates with intermediate cuneiform
• Third metatarsal articulates with lateral cuneiform
• Fourth and fifth metatarsals articulate with cuboid

The second metatarsal base fits into a recess between the medial and lateral cuneiforms, forming a keystone that stabilizes the midfoot.

The Lisfranc ligament is a strong interosseous ligament connecting the medial cuneiform to the base of the second metatarsal. It is the primary stabilizer of the tarsometatarsal joint complex.

• Connects medial cuneiform to second metatarsal
• Prevents separation of first and second metatarsals
• Key stabilizing structure of the midfoot

There is no ligament between the first and second metatarsals, which explains why disruption of the Lisfranc ligament leads to diastasis between these bones.

Lisfranc injuries may occur due to both high-energy and low-energy mechanisms.

• Motor vehicle accidents
• Falls from height
• Sports injuries
• Twisting injury of foot
• Axial load applied to plantar-flexed foot

A classic mechanism involves axial loading of a plantar-flexed foot, which disrupts the Lisfranc ligament and leads to displacement of the metatarsals.

Several classification systems have been proposed for Lisfranc injuries. The Hardcastle classification is commonly used and describes displacement patterns.

• Midfoot pain and swelling
• Difficulty bearing weight
• Tenderness over tarsometatarsal joints
• Bruising on plantar surface of foot
• Instability of midfoot

Plantar ecchymosis is considered a classic clinical sign of Lisfranc injury.

• AP foot radiograph
• Oblique foot radiograph
• Lateral foot radiograph
• Weight-bearing radiographs
• CT scan for detailed fracture assessment

A key radiographic sign is widening between the first and second metatarsal bases, indicating disruption of the Lisfranc ligament.

Management depends on the stability of the injury and the degree of displacement.

• Post-traumatic arthritis
• Chronic midfoot instability
• Persistent pain
• Malunion
• Loss of arch height

• Lisfranc ligament connects medial cuneiform to second metatarsal
• Plantar ecchymosis is classic clinical sign
• Fleck sign indicates Lisfranc ligament avulsion
• Missed injuries lead to midfoot arthritis