Findings:

The long-axis image demonstrates mid substance disruption of the interosseous component of the Lisfranc ligament complex. The short-axis image demonstrates mid substance disruption of the dorsal and interosseous components of the Lisfranc ligament complex.

Differential Diagnosis: Internal derangement of foot

Diagnosis: Lisfranc avulsion fracture

Discussion:

In the general population, injuries to the Lisfranc ligament complex account for lesser than 0.5 percent of all fractures. The injuries occur as a result of high-velocity indirect trauma, such as from a motor vehicle accident, and result in obvious displacement and disruption of the midfoot anatomy.

The Lisfranc joint, or tarsometatarsal articulation of the foot, is named after Jacques Lisfranc, a field surgeon in Napoleon's army.

The Lisfranc joint is a complex skeletal and capsuloligamentous structure that provides significant stability while maintaining the transverse arch of the foot. The Lisfranc joint forms a shallow arc between the medial base of the second metatarsal and the lateral margin of the distal medial cuneiform, a configuration that gives it little bony stabilization. The bony architecture of this joint, specifically the "keystone" wedging of the second metatarsal into the cuneiform, forms the focal point that supports the entire tarsometatarsal articulation.

As many as 20 percent of Lisfranc joint injuries are missed on initial radiographs. MR imaging has been shown to demonstrate the Lisfranc ligament complex reliably in the normal foot. Three distinct structures can be identified: the dorsal, plantar, and interosseous ligaments. MR imaging frequently shows small avulsion fractures that are not visible on radiographs. The fractures usually arise from the base of the second metatarsal, though other midfoot contusions and fractures are often seen as well. Bone marrow edema without avulsions are commonly encountered and are a useful secondary sign raising suspicion for a Lisfranc ligament complex injury.

MR imaging can prove very helpful for the evaluation of injuries to the midfoot, particularly in the setting of normal radiographs. Specific injuries to the components of the Lisfranc ligament complex can be detected. Other injuries to this region that are exclusive of the Lisfranc ligament complex, such as midfoot contusions and fractures, are also well demonstrated. The accurate diagnosis of Lisfranc and related injuries in the patient with midfoot pain allows appropriate conservative or surgical treatment to be instituted.

References:

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2.     Crim J. MR imaging evaluation of subtle Lisfranc injuries: the midfoot sprain. Magn Reson Imaging Clin N Am 2008;16:19–27.

3.     Desmond EA, Chou LB. Current concepts review: Lisfranc injuries. Foot Ankle Int 2006;27:653–660.

4.     Lattermann C, Goldstein JL, Wukich DK, Lee S, Bach Jr BR. Practical management of Lisfranc injuries in athletes. Clin J Sport Med 2007;17:311–315.

5.     Coetzee JC, Ly TV. Treatment of primarily ligamentous Lisfranc joint injuries: primary arthrodesis compared with open reduction and internal fixation. Surgical technique. J Bone Joint Surg Am 2007;89:122–127.