Definition
Lisfanc injuries affect the tarsometatarsal ('Lisfranc') joints anc adjacent bones in the middle of the foot. There is a wide spectrum of injury from simple ligament sprains to severe high-energy injuries with mutliple fractures.
Early identifiaction and treatment of Lisfranc injuries is imprtant as, if not properly treated, they can lead to osteoarthritis and collapse of the midfoot causing long term pain and difficulty with activities.
Mechanism of the injury
Tarso-metatarsal (Lisfranc) injuries may be caused by minor sporting trauma or major injuries such as in falls from height or road traffic accidents. The forces may be applied to the foot directly or indirectly.
Symtoms
The foot becomes painful with swelling and usually bruising over the middle of the foot on the upper surface. Sometimes there is bruising seen in the centre of the sole of the foot ('plantar eccymosis'). If present this sign suggests a significant injury to the midfoot, often involving the Lisfranc joints.
The pain may seem out of proportion to the injury and can be severe even if bruising or swelling are minimal.
Diagnosis
A Lisfranc injury should be suspected if there is tenderness and swelling over the midfoot following injury.
Investigations usually include weright-bearing x-rays if this can be tolerated. MRI or CT scans can also add useful information
If the stability of an injury is in doubt it can be assessed with an examination under anaesthetic.
Medical treatment
Very simple, undisplaced, stable injuries, such as isolated sprains of the Lisfarnc ligament, can be treated conservatively, for example with a period of immobilisation in a fixed angle walker boot.
Surgical treatment
The majority of Lisfranc injuries require surgical intervention to restore and stabilise the bony architecture of the midfoot.
This is usually undertken through an open surgical approach to allow the Lisfranc joint to be re-aligned as accurately as possible and then held in place by a combination of plates and screws. In most cases the metalwork is removed at a later date but your surgeon will discuss the risks and benefits of this with you.
Sometimes, particularly if the Lisfranc joint are badly damaged, it may be better to fuse the joints at the start. Your surgeon will discuss this option with you if he or she feels it might be better in your particular case.
If joint-preserving surgery (or no surgery) has been carried out there is a risk of developing osteoarthritis in the midfoot. This cannot be evaluated until some time after the primary treatment and may mean that secondary surgery, such as a midfoot fusion, is required at a later date.