of the distal
second (marked by the arrow),
third, and
fourth metatarsal bones. In a high energy injury to the midfoot, such as a fall from a height or a motor vehicle accident, the diagnosis of a Lisfranc injury should, in theory at least, pose less of a challenge. There will be deformity of the midfoot and X-ray abnormalities should be obvious. Further, the nature of the injury will create heightened clinical suspicion and there may even be disruption of the overlying skin and compromise of the blood supply. Typical X-ray findings would include a gap between the base of the first and second toes. The diagnosis becomes more challenging in the case of low energy incidents, such as might occur with a twisting injury on the racquetball court, or when an American Football lineman is forced back upon a foot that is already in a fully
plantar flexed position. Then, there may only be complaint of inability to bear weight and some mild swelling of the forefoot or midfoot. Bruising of the arch has been described as diagnostic in these circumstances but may well be absent. Typically, conventional radiography of the foot is utilized with standard non-weight bearing views, supplemented by weight-bearing views which may demonstrate widening of the interval between the first and second toes, if the initial views fail to show abnormality. Unfortunately, radiographs in such circumstances have a sensitivity of 50% when non-weight bearing and 85% when weight-bearing, meaning that they will appear normal in 15% of cases where a Lisfranc injury actually exists. In the case of apparently normal x-rays, if clinical suspicion remains, advanced imaging such as
magnetic resonance imaging (MRI) or
computed tomography (CT scan) is a logical next step.
Classification There are three classifications for the fracture: • Homolateral: All five metatarsals are displaced in the same direction. Lateral displacement may also suggest
cuboidal fracture. • Isolated: one or two metatarsals are displaced from the others. • Divergent: metatarsals are displaced in a
sagittal or
coronal plane and may also involve the
intercuneiform area and include a
navicular fracture. ==Treatment==