LisFranc Fracture

---

Introduction

• Disruption between the articulation of the medial cuneiform and base of the second metatarsal
  • Disruption of the TMT joint complex
  • Injury to 2nd metatarsal àDisruption of other metatarsals
• May take form of purely ligamentous injuries or fracture-dislocations
  • Ligamentous vs. bony injury pattern has treatment implications
• More common in males in their 30s 
• Missed injuries can result in progressive foot deformity, chronic pain and dysfunction
  • Tarsometatarsal fracture-dislocations are easily missed (up to 30% on initial visits) and diagnosis is critical

Mechanism & Pathoanatomy

• Mechanism = indirect rotational forces and axial load through hyperplantar flexed forefoot 
  • Hyperflexion/compression/abduction moment exerted on forefoot and transmitted to the TMT articulation
  • Metatarsals displaced in dorsal/lateral direction 
  • Think of a running back trying to push through lineman or sprinter

 
Anatomy

• Midfoot:
  • Medial, Intermediate (Middle), Lateral Cuneiform
  • Navicular
  • Cuboid
• Lisfranc joint complex consists of three articulations:
  • 1) Tarsometatarsal articulation
  • 2) Intermetatarsal articulation
  • 3) Intertarsal articulations
• Ligaments
  • Lisfranc ligament  
    • Stabilizes 2nd metatarsal and maintenance of the midfoot arch
    • Interosseous ligament that goes from medial cuneiform to base of 2nd metatarsal on plantar surface 
  • No direct ligamentous attachment between first and second metatarsal

Physical Exam

• Symptoms
  • Severe pain and inability to bear weight
• PE
  • Medial plantar bruising with swelling throughout midfoot
  • Tenderness over tarsometatarsal joint
  • Pain with pronation and passive abduction of the midfoot
  • *Instability test
    • Grasp metatarsal heads and apply dorsal force to forefoot while other hand palpates the TMT joints
    • Dorsal subluxation suggests instability
    • If first and second metatarsals can be displaced, global instability is present, and surgery is required
    • When plantar ligaments are intact, dorsal subluxation does not occur with stress exam and injury may be treated nonoperatively
  • Evaluate for compartment syndrome!

 
Imaging

• Radiographs
  • AP, lateral, oblique views
  • Stress -> may be helpful to show instability when non-weight bearing radiographs are normal and there is high suspicion
  • Weight-bearing with comparison view
  • 5 critical radiographic signsthat indicate presence of midfoot instability
    • 1) Discontinuity of a line drawn from the medial base of the 2nd metatarsal to the medial side of the middle cuneiform (diagnostic)
    • 2) Widening of the interval between the 1st and 2nd metatarsal
      • Fleck sign= bony fragment in 1st intermetatarsal space àAvulsion of Lisfranc ligament from base of 2nd metatarsal (diagnostic)
    • 3) Dorsal displacement of the proximal base of the 1st or 2nd metatarsal  
    • 4) Medial side of the base of the 4th metatarsal does not line up with medial side of cuboid 
    • 5) Disruption of the medial column line (line tangential to the medial aspect of the navicular and the medial cuneiform)
• CT scan
  • Useful for diagnosis and preoperative planning
• MRI
  • Can be used to confirm presence of purely ligamentous injury

Treatment

• Nonoperative
  • Posterior splint and non-weightbearing for sprains and non-displaced fractures
    • No displacement on weight-bearing and stress radiographs and no evidence of bony injury on CT (usually dorsal sprains)
  • Cast immobilization for 8 weeks 
• Operative
  • ORIF
  • Any evidence of instability (> 2mm shift)     
  • Favored in bony fracture dislocations as opposed to purely ligamentous injuries
  • Primary arthrodesis 
    • Purely ligamentous arch injuries   
    • Primary arthodesis is an alternative to ORIF in patients with any evidence of instability with possible benefits