34 y M with right midfoot swelling and pain after injuring while playing football. The patient describes a hyper-plantarflexion mechanism. Physical exam notable for bruising to medial plantar foot and diffuse swelling to dorsal midfoot with tenderness to palpation. XR is seen below:
What is the diagnosis?
Lisfranc Injury. Characterized by a disruption of the tarsometatarsal joint complex, specifically the medial cuneiform to the base of the 2nd metatarsal (attachment points of the Lisfranc ligament). Usually from hyper-plantarflexion and axial loading on the joint space. Can range from sprain to fracture-dislocation. If the joint is unstable or if there is displacement of >2mm, or if there is associated fracture rather than purely ligamentous injury this will typically require operative management. Often this will not be seen on ap and lateral images of the foot and will require weight bearing views with comparison to the normal foot. If seen on lateral views it appears as dorsal displacement of the proximal base of the 1st or 2nd metatarsal.
One of the critical findings on weight bearing views is a disruption in a line drawn extending from the medial 2nd metatarsal to the medial middle cuneiform as shown below:
Another radiographic finding is called ‘Fleck’ sign, which is a bony fragment in the first intermetatarsal space caused by an avulsion of the Lisfranc ligament from the base of the 2nd metatarsal. Shown below:
For more info please visit: