Lateral Foot Sprain
The Lisfranc's, or tarsometatarsal joint, forms a bony arc across the midfoot. The diagnosis has been missed in up to 20% of cases. The mechanism of injury is often a misstep or fall with forced planterflexion of the forefoot on the rearfoot. Diffuse swelling across the midfoot is noted with ecchymosis, or bruising noted in the arch. X-ray of both feet can aid in subtle radiographic changes in the injured foot. If there is no displacement on X-ray noted but sprain is considered, an MRI without contrast of the foot will evaluate the integrity of the Lisfranc or medial cuneiform- second metatarsal ligament.
If intact and no displacement or fractures are noted, nonweightbearing cast immobilization is standard treatment for approximately 6 weeks. If displacement or complete tear occurs, surgical reduction and fixation is recommended to stabilize and reduce the fracture. CT scans are utilized for evaluation for better visualization of osseus structures. Accurate anatomic reduction, whether open or closed, provides better functional results. Percutaneous wire or screw fixation to maintain alignment and congruity. If neglected, these injuries can cause chronic pain and necessitate fusion to prevent pain.