Lisfranc Injury

The Lisfranc injury is disruption of the tarsometatarsal joint complex, which links the midfoot to the five metatarsal bases. The key stabilizer is the Lisfranc ligament, running from the lateral face of the medial cuneiform to the medial base of the second metatarsal. Its plantar component is the strongest. The second metatarsal base is recessed between the cuneiforms, and the arch depends on this keystone.

Incidence is about 1 in 55,000 people a year. About 20% are missed at first presentation, and men are affected more often than women. Mechanisms:

• High energy: road traffic collision, crush, fall from height
• Low energy: axial load on a plantarflexed foot (stepping off a kerb, football, horse riding with the foot caught in a stirrup)

Patterns by displacement: homolateral (all five metatarsals shift laterally), isolated (one or two metatarsals), and divergent (the first ray moves medially and the lesser rays laterally). Injuries are stable (no displacement on weight bearing) or unstable.

Anatomic reduction determines outcome. Post-traumatic midfoot arthritis develops in over half of patients with residual displacement. Complications are compartment syndrome, injury to the dorsalis pedis artery and its perforating branch, chronic pain, loss of the arch and complex regional pain syndrome.

• Midfoot pain and swelling, inability to push off or bear weight
• Plantar arch ecchymosis, which is highly suggestive
• Tenderness over the tarsometatarsal joints, pain on passive pronation and abduction of the forefoot while the hindfoot is held, and pain on stress of the second metatarsal head
• Forefoot widening, a flattened arch and a prominent dorsal midfoot
• Red flags: tense swelling, severe pain on passive toe extension, absent dorsalis pedis pulse, open wound, and inability to weight bear despite normal early radiographs

• Weight bearing radiographs of both feet (anteroposterior, lateral and 30 degree medial oblique). If the patient cannot stand, use simulated weight bearing with axial load.
• Alignment criteria: the medial border of the second metatarsal base lines up with the medial border of the middle cuneiform on the anteroposterior view, and the medial border of the fourth metatarsal base lines up with the medial border of the cuboid on the oblique view. A gap over 2 mm between the first and second metatarsal bases, a fleck of bone in that gap, dorsal displacement of the metatarsal base on the lateral view, or widening over 2 mm compared with the other foot indicates injury.
• CT to define subtle diastasis, comminution and associated fractures of the cuneiforms, cuboid and navicular.
• MRI when radiographs are normal and suspicion persists, for ligament integrity.
• Stress views under anesthesia (abduction and pronation) when equivocal.

Differentials: midfoot sprain, cuboid fracture, navicular stress fracture, metatarsal base fracture, early Charcot arthropathy, tibialis posterior tendinopathy.

Stable injury: non-weight-bearing short leg cast for 6 weeks, then a walking boot for 4 to 6 weeks with a rigid arch support, and review with weight bearing radiographs at 2 weeks to detect late displacement.

Unstable or displaced injury (over 2 mm):

• Surgery within 1 to 2 weeks, once swelling allows. Immediate surgery for open injury, vascular compromise or compartment syndrome.
• Open reduction and internal fixation: transarticular 3.5 or 4.0 mm screws from the medial cuneiform to the second metatarsal base, dorsal bridge plates across the first to third tarsometatarsal joints, and 1.6 mm Kirschner wires for the fourth and fifth rays.
• Primary arthrodesis of the first to third tarsometatarsal joints is an option for purely ligamentous injury, with a lower need for later hardware removal.
• Compartment syndrome: fasciotomy through two dorsal incisions and a medial incision.
• Cefazolin 2 g IV 30 to 60 minutes before incision (3 g if over 120 kg).
• Enoxaparin 40 mg SC daily while non-weight-bearing.

Postoperative care: non-weight-bearing in a splint then cast for 6 to 8 weeks, then a boot with progressive weight bearing. Remove transarticular screws crossing mobile lateral joints at 3 to 4 months. Fused segments may keep their hardware. Return to sport takes 6 to 12 months.

Analgesia: paracetamol 1 g orally every 6 hours (maximum 4 g/day) with ibuprofen 400 mg orally every 8 hours with food for up to 7 days. Children: paracetamol 15 mg/kg every 6 hours and ibuprofen 10 mg/kg every 8 hours.

Follow up at 2 weeks, 6 weeks, 3 months, 6 months and 12 months. Counsel on arthritis risk, which may need later midfoot fusion, and on return to running only after union.