The other day I posted radiographs of proximal metatarsal fractures and posed the question: Is this the dreaded “Lisfranc fracture?”
It turns out that this is a complicated question. Lets dive into what the heck a “lisfranc fracture” means.
The Lisfranc joint is another name for the tarsometatarsal joint of the foot. It is named after Jacques Lisfranc (1790-1847) who was a surgeon in Napoleon’s army who basically pioneered amputating toes at the tarsometatarsal joint in order to treat gangrene. The joint contains 5 metatarsals that articulate with 3 cuneiforms and the cuboid. It is a complicated structure both radiographically and anatomically with mutliple ligaments and bones. This poses difficulty in identifying exactly what is mean’t when people discuss the “Lisfranc fracture” or “Lisfranc fracture-dislocation.”
Anytime something has multiple bones it becomes difficult to identify subtle radiographic findings. And it can be missed! Subtle Lisfranc injuries can happen and can cause significant morbidity if not treated correctly, usually surgically. There is a classification of Lisfranc joint injuries posed by Hardcastle et al (1) that is commonly used by our bone brotheren (orthopedics). I refer you to their article for details.
Radiographically you can have multiple findings from subtle to obvious. Here are some key points and things to look for:
- Always obtain 3 views of the foot: AP, lateral, and 30 degrees oblique
- Weight bearing views can show subtle widening of articulation spaces and point out instability due to lisfranc ligamentous injuries
- On the AP view, any diastasis of more than 2mm between the base of the 1st and 2nd metatarsals suggest Lisfranc injury
- On the lateral view, the superior border of the base of the first metatarsal should align with the superior border of the medial cuneiform
- On the oblique view, the medial border of the fourth metatarsal should align with the medial border of the cuboid
- A “fleck” sign on the AP view, or an avulsion off the base of the of the second metatarsal or medial cuneiform is a sign of a Lisfranc ligament* injury
- CT and/or MRI have been advantageous in radiographically subtle Lisfranc injuries
*The lisfranc ligament traverses the base of the 2nd metatarsal to the medial cuneiform.
The bottom line is these are highly morbid injuries if not treated correctly (and many times even if treatment is optimized). Orthopedics will often take the patient for operative fixation in order to anatomically align the joint for best long-term result.
Lets re-visit our radiograph and identify if we are concerned:
Fig. 1: (AP View) No diastasis of more than 2mm. Also one can see that the lateral border of the 1st Metatarsal is aligned with the lateral border of the medial cuneiform bone. The medial border of the second metatarsal is aligned with the medial border of the middle cuneiform bone. This is good alignment and indicates the Lisfranc ligament extending from the base of the second metatarsal to the medial cuneiform is intact.
Fig. 2: (Lateral view) The superior borders of the medial cuneiform and the base of the 1st metatarsal align
Fig. 3: (Oblique view) The medial border of the base of the 4th metatarsal aligns with the medial border of the cuboid.
If you look at all the criteria above you’ll realize that this gentleman only has non-displaced fractures of the proximal 3rd and 4th metatarsals, no signs consistent with injury to the Lisfranc joint. Consider weight bearing views or CT scan in this case to fully rule out a Lisfranc joint injury.
For a good radiograph showing Lisfranc fracture-dislocation please refer to reference #2 below, or stay tuned and I’ll try and dig one up!
1. Rijn J, Dorleijn D, Boetes B, Wiersma-Tuinstra S, Moonen S. Missing the Lisfranc Fracture: A Case Report and Review of the Literature. J Foot & Ankle Surg 51: 270-274, 2012.
2. Broder JS. Diagnostic Imaging for the Emergency Physician. Elsevier 2011. Figure 14-123 Pg. 830.