Definition
The lisfranc joint is named after one of the Napolean war’s surgeons. It is anatomically situated in the middle of the length of the foot between the heel and the toes. These joints do not move a lot but serve more to adapt the foot to the ground and as suspension. If the joint is disrupted, often with some skeletal fragments, the alignment of the foot becomes grossly disturbed and if untreated leads to osteoarthritis and painful ambulation.
Mechanism of the injury
Tarso-metatarsal (Lisfranc) injuries are caused by direct or indirect forces.
Direct forces include a crush injury (MVA or industrial) or a direct blow. These may be combined with soft-tissue injury and present as open fractures.
Indirect injuries are more common. They result from an axial load to a plantarflexed foot. They may occur during sports, or stepping down from a stair or sidewalk.
Symtoms
There is midfoot swelling, usually dorsal. There is often an area of plantar medial ecchymosis ( bleeding).
There is pain seemingly out of proportion to the injury. Unlike a routine ankle sprain, these injuries elicit patients’ comments of a visceral nature like “I almost passed out”, “I almost threw up”.
Diagnosis
Upon trauma suspicion should be raised if there is tenderness and swelling in the TMT –joints.
This should whenever possible lead to weight-bearing X-rays ( usually difficult because of pain) which are usually diagnostic with incongruence or disruption of the tarsometatarsal joints. If there is doubt a CT ( Computer tomography) is advocated.
If anesthesised instability can be confirmed, during radiographic exam.
Medical treatment
These injuries are very rarely thought to be suitable for a non-surgical treatment. If examined with stress-views under anesthesia the instability becomes obvious and to preserve function surgical stabilisation is usually recommended.
Surgical treatment
Technically the surgery could be done without opening the joints and with c-arm control, but often it is not possible to accurately reduce the joint-complex in this manor. Therfore in most cases the midfoot is exposed and stabilised with screws / pins or plates in an anatomic position.
In the instances where there are no joint fragments ( true ligamentuous injuries) it has been shown that improved results can be achieved wuth a primary arthrodesis.
The exact treatment is always to be decided by the attending surgeon who will tailor the treatment indvidually to his expertise.
Often screws and plates are used to stabilise the ligament-repair and removal is recommended within some months after the fixation to restore the joint- function.
There is a risk of development of late osteoarthritis in the joint also after surgery, and as this cannot be evaluated until some time after the primary treatment necessity for secondary surgery might evolve.