A Hop, Skip and a Jump: Lisfranc Injuries in the Emergency Department
“Lisfranc injuries are relatively rare, occurring at a rate of one person per 55,000 population per year, and result from direct and indirect forces acting on or through the Lisfranc joint of the foot.”
Case
A 32-year-old male with no pertinent past medical history presents to the ED for evaluation of a right foot injury after attempting a backflip jumping off a trampoline the day prior. He reports severe pain and swelling in the right mid-foot and has been unable to bear weight on that foot.
Physical exam is significant for normal vital signs and significant right foot swelling and tenderness to palpation over the first, third and fourth metatarsals. The foot is held in a slightly plantar-flexed position, and the patient has difficulty with dorsiflexion. There is intact dorsalis pedis and posterior tibial pulses. Sensation to light touch is intact in the distal toes.
The patient is sent for x-ray imaging (Figure 1) which shows a possible avulsion injury of the metatarsals but is otherwise unremarkable for obvious bony abnormality.
Figure 1: AP view of the right foot without obvious abnormality
Diagnosis
The patient is still having significant pain and inability to bear weight, and so a CT of the foot without contrast is performed, which shows fractures of the first, third, and fourth metatarsals, with disruption of the Lisfranc joint.
Discussion
Lisfranc injuries are relatively rare, occurring at a rate of one person per 55,000 population per year, and result from direct and indirect forces acting on or through the Lisfranc joint of the foot. These injuries tend to occur more in males than females, and most commonly occur within the third decade of life. The mechanism of injury usually involves a high-force trauma, and commonly results from motor vehicle accidents, falls from a height, and athletic injuries. Hyper-plantarflexion of the flexed forefoot transmits force to the tarso-metatarsal (TMT) junction and results in displaced metatarsals in a dorsal/lateral direction.
Lisfranc injuries can range from mild sprains to severe fracture-dislocations. There are a few different classification systems used to describe Lisfranc injuries, which are more commonly used by orthopedics for planning non-operative vs. operative management. Nunley et al [4] described a new classification system (Figure 3) that is commonly used in athletes and is based on clinical exam and imaging studies. Stage I is a sprain to the Lisfranc ligament with no diastasis or arch height loss seen on radiographs, but increased uptake on bone scintigrams. Stage II sprains have a first to second intermetatarsal diastasis of 1–5 mm because of failure of the Lisfranc ligament, but no arch height loss. Stage III sprains display first to second intermetatarsal diastasis and a loss of arch height, as represented by a decrease or inversion of the distance between the plantar aspect of the fifth metatarsal bone and the plantar aspect of the medial cuneiform bone on an erect lateral radiograph.
Figure 2: Nunley Classification System of Lisfranc injuries
Radiographs are the first step in making the diagnosis of a Lisfranc injury. Common radiographic findings that indicate presence of midfoot instability are widening of the interval between the first and 2nd metatarsal with a bony fragment (fleck sign) in the first intermetatarsal space (Figure 3); dorsal displacement of the proximal base of the first or second metatarsals. A toe dislocation may be an indirect consequence and pathognomonic sign of a Lisfranc injury. Computed tomography (CT) imaging may be necessary for diagnosing subtle injuries if x-rays are inconclusive.
Figure 3: "Fleck sign" on an AP radiograph of the foot
Fractures and dislocations of the tarsometatarsal (Lisfranc) joint are frequently overlooked or misdiagnosed, primarily due to the low incidence of these injuries and variations in the pattern of injury and clinical presentation. The importance of careful physical and radiological examination of these patients cannot be overestimated because up to 20% of such injuries are missed at initial presentation. Missed injuries can result in progressive foot planovalgus deformity.
Treatment generally ranges from closed reduction and non-weight-bearing cast for 4-8 weeks in patients with contraindications to more aggressive management, to primary arthrodesis for more severe injuries.
Case Resolution
The patient was provided pain control, placed in a posterior leg splint, made non-weight bearing, and was provided with orthopedics follow-up for definitive management of his Lisfranc injury.
Take-Aways
1. Lisfranc injuries are rare, easily overlooked, and can lead to long-term disability.
2. If x-ray imaging is not definitive, it is important to have high clinical suspicion and obtain advanced imaging with either CT or MRI to assess for Lisfranc injuries.
3. Management in the ED includes placing of a splint. Definitive orthopedic management ranges from closed reduction, percutaneous pinning, to ORIF and primary arthrodesis in more severe cases.
Author: Lindsey Brown, MD is a first-year emergency medicine resident at Brown University Emergency Medicine Residency.
Faculty Reviewer: Kristina McAteer, MD is an attending emergency medicine physician at Rhode Island Hospital and Newport Hospital.
References
1. Grewal US, Onubogu K, Southgate C, Dhinsa BS. Lisfranc injury: A review and simplified treatment algorithm. Foot (Edinb). 2020 Dec; 45:101719. doi: 10.1016/j.foot.2020.101719. Epub 2020 Jul 6. PMID: 33038662.
2. Mulcahy H. Lisfranc Injury: Current Concepts. Radiol Clin North Am. 2018 Nov;56(6):859-876. doi: 10.1016/j.rcl.2018.06.003. Epub 2018 Sep 17. PMID: 30322487.
3. Mulier T, de Haan J, Vriesendorp P, Reynders P. The Treatment of Lisfranc Injuries: Review of Current Literature. Eur J Trauma Emerg Surg. 2010 Jun;36(3):206-16. doi: 10.1007/s00068-010-1034-5. Epub 2010 Jun 1. PMID: 26815863.
4. Nunley J, Vertullo C. Lisfranc injuries in the athlete. Am J Sports Med 2002;30:871–878.