A 60 year old male diabetic with a history of diabetic neuropathy, peripheral vascular disease and left first toe amputation presents to the ED with left foot pain after a recent fall. His pain is worse with weight bearing.
On exam, the patient is noted to have swelling and tenderness to the left midfoot. He has ecchymosis to the plantar surface as well as pain with pronation and supination of the midfoot foot.
You obtain the following X-ray. What is the diagnosis?
Answer: Lisfranc fracture-dislocation
The Lisfranc injury is a diagnosis that requires a high index of suspicion, as it is easily missed and can lead to significant morbidity including post-traumatic arthritis and midfoot instability.
Lisfranc was the name of a surgeon in Napoleon’s army who described a new method of amputation across the tarsometatarsal joints, which was utilized in situations of wet gangrene from frostbite. The injury itself was later named for horseback riders who got their foot caught in the stirrup upon falling off of the horse.
The lisfranc joint consists of 5 tarsometatarsal joints, with the first through third articulating with the medial, middle and lateral cuneiforms, respectively, while the 4th and 5th articulate with the cuboid bone. The lisfranc ligament originates from the medial cuneiform and extends to the base of the second metatarsal. It is responsible for the stability of the midfoot. A lisfranc injury refers to any fracture or dislocation of a tarsometatarsal joint.
The typical mechanism of injury involves high-energy trauma with plantar flexion and forced pronation or supination. However, up to 1/3 of injuries are from a minor fall. In diabetic patients, especially those with peripheral neuropathy, these injuries can occur from minimal or no trauma.
The clinical presentation includes pain to the midfoot, worse with weight bearing. Physical exam may reveal exaggerated swelling to the midfoot, ecchymosis along the plantar midfoot, pain and tenderness along the tarsal-metatarsal joints, and pain with pronation or supination of the midfoot with the heel fixed in the examiner’s hand. Always look for signs of compartment syndrome as the dorsalis pedis can be injured in severe dislocation.
On radiographs, look for fracture of the base of the second matatarsal. Another hallmark of a lisfranc injury is that the medial margin of the 2nd metatarsal base does not align with the medial margin of the second cuneiform. Dislocations are considered unstable if there is 1 mm or more displacement between the base of the first and second metatarsal. In lateral views, the 2nd metatarsal is higher than the middle cuneiform.
For nondisplaced fractures with < 1 mm between the first and second metatarsal bases, treatment is typically conservative management, with non-weight bearing to the affected foot, splinting and orthopedic follow up. For displaced fractures, emergent ortho consult is required as most of these will require operative management.