What is the role of plain radiography in the diagnosis of Lisfranc fracture dislocation?

Updated: Apr 20, 2020
  • Author: Nirmal Tejwani, MD, MPA; Chief Editor: Thomas M DeBerardino, MD  more...
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Answer

Obtain initial radiographs of the injured foot in all patients, as follows:

  • Anteroposterior (AP) view of the foot in a standing position, if possible - In the normal image, the medial border of the base of the second metatarsal (MT) and the middle cuneiform should line up; any gross diastasis greater than 2 mm between the bases of the first and second MTs suggests a Lisfranc injury (see the first and second images below)
  • Lateral view of the foot in a standing position, if possible - In this view, the superior border of the first MT base should align with the superior border of the medial cuneiform (see the third image below)
  • Medial 30º oblique view of the foot - In this view, the medial border of the cuboid should align with the medial border of the fourth MT (see the fourth and fifth images below)
In this anteroposterior radiograph of a Lisfranc d In this anteroposterior radiograph of a Lisfranc dislocation, note the disruption of the normal second tarsometatarsal alignment.
Standard anteroposterior radiograph demonstrates a Standard anteroposterior radiograph demonstrates a Lisfranc fracture dislocation. Determining the extent of fracture involving the joint is difficult with plain radiographs.
In this lateral radiograph of a typical Lisfranc i In this lateral radiograph of a typical Lisfranc injury, note the malalignment of the metatarsal bases with the midfoot.
In this medial oblique radiograph of a normal foot In this medial oblique radiograph of a normal foot, note the medial borders of the cuboid and fourth metatarsal base. They should be even, as depicted by the black lines.
In this medial oblique radiograph of a Lisfranc in In this medial oblique radiograph of a Lisfranc injury, note the loss of alignment between the cuboid and fourth metatarsal base (black lines). This is diagnostic of a Lisfranc injury and is as important as recognition of the second tarsometatarsal instability.

If a subtle injury is suspected, it is advisable to obtain a weightbearing AP view of both feet on the same cassette for direct comparison. Additionally, a stress-view radiograph can be performed in which the hindfoot position is maintained while the midfoot and forefoot are forced into pronation and abduction; this will demonstrate lateral subluxation of the first and second tarsometatarsal (TMT) joints with instability (see below).

A “fleck sign” seen on the AP radiograph is pathognomonic for a Lisfranc injury. This sign is reportedly present in 90% of Lisfranc ligament injuries. It represents an avulsion fracture from either the second MT base or the medial cuneiform, resulting from forceful abduction of the forefoot that avulses the strong Lisfranc ligament between the base of the second MT and the medial cuneiform.

The literature offers many approaches to classifying Lisfranc injuries on the basis of radiographic appearance. The value of these classifications is for reporting only. For the purposes of treatment, the major determinant is whether the joint complex is stable or unstable. This is determined by the radiographic stress views (see Procedures).


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