Lisfranc injury

Introduction

Lisfranc injuries are severe injuries to the tarsometatarsal (Lisfranc) joint between the medial cuneiform and the base of the 2^nd metatarsal. They can be either solely ligamentous injuries or involving the bony structures of the midfoot (termed a “fracture-dislocation”).

Lisfranc injuries are unfortunately often missed due to their subtle radiological features, but prompt diagnosis is crucial as neglected injury can lead to ongoing midfoot pain, instability, and deformity.

The inherent stability of the Lisfranc joint is normally provided by the “keystone” configuration of base of the second metatarsal fitting into a mortise created by the medial and middle cuneiforms (Fig. 1). Multiple interosseous ligaments support this area, of which the Lisfranc ligament (from the medial cuneiform to the base of the second metatarsal) is the largest and strongest.

By TeachMeSeries Ltd (2020)

Figure 1 – The tarsal bones of the foot

Clinical Features

Lisfranc injuries most commonly occur following severe torsional or translational forces applied through a plantar flexed foot, therefore commonly occur as road traffic accidents or athletic injuries. Following the injury, patients will report severe pain in the midfoot and difficulty in weight-bearing.

On examination, there will be swelling and tenderness over the midfoot*; plantar bruising is highly suggestive of a Lisfranc injury. Pain may be provoked by stressing the midfoot.

Patients with tarsometatarsal injuries, resulting from high-energy mechanisms or which result in a significant amount of swelling, should be monitored for features of compartment syndrome.

*The ‘piano key’ sign is prominence of the metatarsal bones, which reduce back down with pressure

Differential Diagnosis

Patients presenting with midfoot pain following high-energy injuries should also be assessed for ankle fractures, other tarsal fractures, or proximal metatarsal fracture.

Investigation

Any patient involved in a trauma or high-energy injury should be managed and investigated as per ATLS guidelines.

First line imaging for suspected Lisfranc injury is with plain film radiograph, which should include antero-posterior, oblique, and lateral foot views whilst weight-bearing. However, obvious widening of tarsometatarsal joint is not always apparent in Lisfranc injuries*.

CT scanning is useful in the pre-operative planning of more comminuted fractures. MRI imaging can confirm the presence of purely ligamentous injury.

*Weight bearing films can also be obtained to help diagnosis if uncertainly / as comparison, when force is applied through the TMT joint complex, there will be increased displacement of Lisfranc joint

James Heilman, MD, CC BY-SA 4.0 , via Wikimedia Commons

Figure 2 – Lisfranc injury to the left foot (arrow)

Classification

The Hardcastle and Myerson classification can be used to classify Lisfranc injuries:

• Type A – complete homolateral dislocation
• Type B1 – partial injury, medial column dislocation
• Type B2 – partial injury, lateral column dislocation
• Type C1 – partial divergent dislocation
• Type C2 – complete divergent dislocation

Management

In trauma patients, ensuring the haemodynamic stability of the patient is essential, before any further injuries are managed

For significantly displaced injuries, closed reduction may be required in A&E to correct any gross deformity and help protect the soft-tissue envelope. This involves gentle traction to the midfoot and then a corrective pressure to the metatarsal base, before being placed in a backslab.

Certain Lisfranc injuries without significant displacement can be primarily managed conservatively with cast immobilisation / air-cast boot and non-weight-bearing mobilisation for 6-12 weeks, with regular orthopaedic follow-up and review.

Surgical Intervention

Patients with clear displacement must be managed operatively. Temporary external fixation can be used if there is significant soft tissue swelling making the injury not amenable to surgery in the first instance.

Definitive fixation most commonly involves screw fixation between the medial cuneiform and second metatarsal, between the medial cuneiform and the first metatarsal, and between the middle cuneiform and second metatarsal. Occasionally, small region specific plate systems can be used.

Primary arthrodesis can be used for severely comminuted or displaced fracture-dislocations.

James Heilman, MD, CC BY 3.0 , via Wikimedia Commons

Figure 3 – Lisfranc fracture with fractures of the 2nd to 4th distal metatarsals

Complications

Post-traumatic arthritis is the most common complication following a Lisfranc injury, occurring in up to 25%. It is more common in those with a delayed management by ORIF or those with a non-anatomical reduction; in such cases, they may require midfoot arthrodesis.

Midfoot compartment syndrome is an important complication that can occur following Lisfranc injuries, presenting acutely following the initial injury.