What is a Lisfranc Injury?
Lisfranc injuries or fractures are midfoot injuries where the metatarsal bone displaces from the tarsal bone. It predominantly occurs at the 2nd tarsometatarsal joint and the corresponding Lisfranc ligament. Injuries can range from a subluxation of the joint to a dislocation involving a fracture.
Anatomy of the Midfoot
Five bones, the cuboid, navicular and three cuneiform bones create the midfoot where they articulate with the five metatarsal bones. Damage to these articulations are known as Lisfranc injuries and are most commonly seen between the medial cuneiform bone and the second and third metatarsal bones. Several ligaments support the mid foot however the dorsal aspect (topside) of the joints in the midfoot is weaker than the plantar aspect.
Hardcastle Classification of Lisfranc Fractures
- Homolateral – all five metatarsals are displaced, may also involve a fracture of the cuboid bone
- Isolated – one or two metatarsals are displaced
- Divergent – metatarsals are displaced in different directions and may also include a fracture of the navicular bone
In 1815, Jacques Lisfranc de St Martin, a French surgeon and gynaecologist, first described the injury after witnessing several fractures or even amputations in the midfoot region, amongst cavalry men on horseback.
Direct force to the dorsum of the midfoot is the most common cause of Lisfranc injuries. They are often seen in crush injuries due to road traffic accidents, falls from a height or work place related accidents where a heavy weight is dropped on the midfoot or the foot is run over by a vehicle. Indirect trauma accounts for one third of Lisfranc injuries and can occur when excess rotational force is applied to a pointed (plantar flexed) foot. Examples of this kind of injury include getting a foot stuck in a drain cover and falling forwards, a person falling off a horse with their foot remaining in the stirrup, or a footballer being tackled while kicking the ball.
People who participate in snowboarding, wake boarding and kite boarding as well as other sports that require bindings secured over the metatarsal bones risk injury to this area by falling with their feet remaining in the bindings. Ballet dancers may also sustain a Lisfranc injury during a pirouette or a spinning motion performed on a pointed foot. Often there is other soft tissue damage or vascular compromise involved potentially making recovery complicated.
Diagnosis of a Lisfranc fracture is usually confirmed through a subjective assessment, confirming the mechanism of injury as well as an x-ray checking for any skeletal deformity. Patients might report an inability to weight bear, especially difficulty walking downstairs and there may be swelling over the midfoot. Weight bearing x-rays can be very helpful in the diagnosis of a Lisfranc injury. If the patient finds it too painful to weight-bear initially then it may be worth waiting a week to allow acute inflammation to resolve before taking x-rays. Another assessment tool that is supportive of a Lisfranc injury is the presence of plantar ecchymosis. This is a flat, purple or blue patch of discolouration on the sole of the foot, similar to a bruise however without any raised surface or swelling. The discolouration is caused by capillaries which have burst due to trauma to the foot. 20-40% of Lisfranc injuries are initially missed(1) and there can be debilitating consequences, including vascular compromise due to a missed or incorrect diagnosis. Early diagnosis and management are imperative to avoid developing complications such as post traumatic arthritis.
Treatment of Lisfranc Injuries
Treatment is either conservative or surgical and patients are usually required to be non-weight bearing while awaiting an orthopaedic review to prevent doing further damage to the foot.
Non-surgical management should only be for patients without any instability or diastasis (separation) of tarsometatarsal joints evident on weight bearing x-ray. If the fracture displacement is less than 2mm then management has traditionally been a plaster cast for six weeks. More recently however, specialists have prescribed a short walker boot for two weeks of protective weight bearing, then have the patient reassessed with a second set of weight bearing x-rays for comparison. If there is no tenderness over the tarsometatarsal joint and no diastasis on x-ray, then weight bearing in a walker boot can continue for a further six to eight weeks. A gradual return to weight bearing can then commence ensuring the patient is wearing appropriate supportive, stiff soled shoes. Patients can expect a period of 6-12 months before making a full return to competitive sport.
Surgical intervention is usually an Open Reduction and Internal Fixation (ORIF) of the fracture although other techniques may include a percutaneous reduction, performed through the skin. While a percutaneous technique is preferable due to being minimally invasive, having fewer complications and allowing for early rehabilitation, it can only be performed on fractures that have been diagnosed early and therefore have less soft tissue swelling. Post-operatively, patients are non-weight bearing for two to four weeks with their ankle and foot immobilised in a cast or boot. Once they are out of the boot and have any range of motion restrictions lifted, standard post-operative physiotherapy is vital to not only the foot, but ankle as well to regain movement and strength and return gait pattern to normal. Thorough rehabilitation will help to avoid post-op complications and developing arthritis in the foot at a later date.
(1) Desmond, E. A., & Chou, L. B. (2006). Current Concepts Review: Lisfranc Injuries. Foot & Ankle International, 27(8), 653–660.