Sunday, March 22, 2015

Foot Pain Out of Proportion to Exam: Lisfranc Injuries

Author: Alexandra Murray, OMSIV
Ohio University Heritage College of Osteopathic Medicine

Originally Published: Modern Resident, February-March 2015

Classic medical conditions that are associated with “pain out of proportion to exam” include compartment syndrome, necrotizing fasciitis and mesenteric ischemia.[1-3] However, another condition that can present with excruciating pain, despite underwhelming exam findings, is a Lisfranc injury.[4-6] Lisfranc injuries encompass a broad spectrum of injuries to the tarsometatarsal (TMT) joints that separate the mid-foot and forefoot. These injuries can be purely ligamentous or involve the osseous and articular structures, resulting in dislocation and/or fracture.[4-6]

Lisfranc injuries comprise only 0.2% of all fractures and can result from direct or indirect trauma. Most cases are associated with high-energy motor vehicle accidents (i.e., ATV accidents) where there is a crush injury to the foot. Indirect trauma from a twisting injury combined with axial loading of the foot can also result in plantar displacement (i.e., sports injury or falling from a step). Most Lisfranc injuries are closed without obvious deformity, making the injury difficult to diagnosis.

Patients typically present with a painful, swollen mid-foot with possible ecchymosis to the plantar aspect.[5,6] Weight bearing is not tolerated, but the patient may have relatively minor pain at rest. Side to side compression of the mid-foot should be painful and may be needed to elicit the diagnosis.[4-6] X-rays of the foot should include three views and, if possible, these images should be taken while weight bearing.[4-6] Non-weight bearing radiographs may not demonstrate an appreciable displacement of the osseous structures, causing the injury to be initially overlooked in up to 50% of cases.[6] Dislocations and fractures are commonly found in combination. An avulsion fracture of the base of the second metatarsal or medial cuneiform, referred to as a “fleck sign,” can often be seen with Lisfranc injuries.[4-6]

Treatment of all Lisfranc injuries requires urgent orthopedic evaluation and follow up, whether treated conservatively or surgically.[4-6] Without treatment, many Lisfranc injuries progress to post-traumatic arthritis, worsening instability and deformity.[4-6] These injuries need anatomical reduction to improve outcome, which can generally only be accomplished with surgery.[4-6] Patients should be placed in a non-weight bearing cast until orthopedic evaluation can be performed.[5]

Lisfranc injuries comprise a spectrum of injuries to the tarsometatarsal joints that can present with foot pain out of proportion to exam.[4-6] These injuries may appear relatively benign; however, it is important to keep in mind that even significant injuries can reduce spontaneously, thereby hiding the initial deformity.[4] Therefore, it is important that the clinician keep a high index of suspicion for this type of injury in any patient with pain and swelling over the mid-foot.

References:
  1. Murdock M, Murdoch MM. Compartment syndrome: A review of the literature. Clin Podiatr Med Surg. 2012 Apr;29(2):301-10.
  2. Hussein QA, Anaya DA. Necrotizing soft tissue infections. Crit Care Clin. 2013 Oct;29(4):795-806.
  3. Renner P, et al. Intestinal ischemia: Current treatment concepts. Langenbecks Arch Surg. 2011 Jan;396(1):3-11.
  4. Loveday D, Robinson A. Lisfranc injuries. Br J Hosp Med (Lond). 2008 Jul;69(7):399-402.
  5. Eleftheriou KI, Rosenfeld PF, Calder JD. Lisfranc injuries: An update. Knee Surg Sports Traumatol Arthrosc. 2013 Jun;21(6):1434-46.
  6. Welck MJ, Zinchenko R, Rudge B. Lisfranc injuries. Injury. 2014 Dec 10. pii: S0020-1383(14)00612-3. doi: 10.1016/j.injury.2014.11.026. [Epub ahead of print].

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