Lisfranc Injury (Tarsometatarsal Joint Injury)

Anatomy & Biomechanics

• The second metatarsal is the keystone, recessed between the medial and lateral cuneiforms - this makes it the most vulnerable to fracture
• Transverse stability is provided by the wedge-shaped metatarsal bases and cuneoform-cuboid articulations
• Longitudinal stability depends almost entirely on ligamentous support
• Strong intermetatarsal ligaments connect the bases of metatarsals 2-5, but there is no ligament between the 1st and 2nd metatarsal bases
• The Lisfranc ligament (the key stabilizer) runs from the medial cuneiform to the base of the second metatarsal

• Medial: 1st metatarsal, medial cuneiform, navicular facet
• Middle: 2nd and 3rd metatarsals with their cuneiforms
• Lateral: 4th and 5th metatarsals with the cuboid

Epidemiology & Mechanisms

• Historically described in equestrian riders whose foot caught in the stirrup during a fall from a horse
• High-energy mechanisms: Motor vehicle crashes, industrial crush injuries - typically produce fracture-dislocations
• Low-energy mechanisms: Sports (football, basketball), axial load on a plantarflexed foot (e.g., stepping off a curb, jumping) - typically produce ligamentous injuries
• Recent evidence suggests >50% of injuries result from low-energy mechanisms (Rosen's)
• Diagnosis is missed on initial presentation in up to 30% of cases, especially with low-energy mechanisms

Classification

Myerson Classification (modification of Quénu-Küss / Hardcastle)

Nunley Classification (low-energy/ligamentous injuries)

Clinical Features

• Midfoot pain, swelling, and inability to bear weight (especially on toes)
• Plantar ecchymosis (bruising under the midfoot arch) - highly specific sign of Lisfranc injury
• Tenderness along the TMT joint line
• Pain on passive pronation/abduction of the forefoot (stress testing)
• "Piano key" test: dorsal-plantar stress on individual metatarsals elicits pain
• Campbell's: Compartment syndrome, though rare, can occur with high-energy injuries - presents with severe swelling and must be promptly decompressed.

Imaging

Plain Radiographs (first line)

• AP, lateral, and 30-degree oblique views of both feet
• Weight-bearing films are preferred but often impossible acutely

CT Scan

• Recommended when X-rays are equivocal
• Better delineation of bony structures, detects occult fractures and subluxations
• Weight-bearing CT (where available) is very useful for subtle instability
• Limitation: still fails to detect many isolated ligamentous injuries

MRI

• Most sensitive and specific for ligamentous injury
• Strong correlation with intraoperative instability
• Best reserved for suspected purely ligamentous injury with normal CT

Stress Fluoroscopy

• Can be used under anesthesia by orthopedics for definitive assessment of instability

Ultrasound

• Can evaluate the dorsal Lisfranc ligament; utility for detecting instability is unproven

Emergency Department Management

1. Apply Ottawa Ankle Rules - can safely exclude midfoot fractures if no bony tenderness at the navicular or 5th metatarsal base, and patient can bear weight
2. Splint, elevate, and apply ice in the ED
3. Orthopedic consultation for any displaced injury or suspected compartment syndrome
4. Compartment syndrome is an emergency - requires fasciotomy (medial incision for deep/abductor hallucis compartments + two dorsal incisions between metatarsals)

Definitive Treatment

Non-operative (Nunley Stage I / nondisplaced injuries)

• Non-weight-bearing short leg cast for 6 weeks
• Then weight-bearing cast for an additional 4-6 weeks
• Serial radiographs to confirm maintained alignment
• Requires strict criteria: displacement <2 mm, ligamentous stability confirmed

Operative (displaced injuries)

• Preferred over closed reduction for most displaced injuries
• Closed reduction (with finger traps, countertraction, percutaneous bone clamps) acceptable if displacement is not severe
• K-wires: used for the lateral two joints but may lose reduction in the medial and middle columns
• 4-mm cannulated or standard partially-threaded cancellous screws: excellent fixation for medial and middle columns, inserted under image control
• Dorsal/medial plating: avoids articular surface damage; fixation strength comparable to transarticular screws

• Reserved for severely comminuted fractures or significant articular damage
• Growing evidence (2024 meta-analyses) that primary arthrodesis vs. ORIF shows no significant difference in return to sport or complications for purely ligamentous injuries - PMID 40020966 and PMID 39680239

Complications

Key Points Summary

• The Lisfranc ligament (medial cuneiform to 2nd metatarsal base) is the primary stabilizer; there is no intermetatarsal ligament between metatarsals 1 and 2
• The fleck sign on X-ray is pathognomonic
• Plantar ecchymosis is highly specific clinically
• Missed in ~30% of cases on initial ED visit
• Any diastasis >2 mm is considered unstable and surgical
• Recent meta-analyses (2024-2025) show no significant difference between ORIF and primary arthrodesis in outcomes for purely ligamentous Lisfranc injuries