Lisfranc Injuries
Description:
The “Lisfranc joint complex” (see figure 1) describes the tarsometatarsal (TMT) articulation of the midfoot while the “Lisfranc joint” refers to the articulation between the first and second metatarsals (MT) with the medial and intermediate cuneiform bones, respectively. The “Lisfranc ligament” originates from the lateral surface of the medial cuneiform bone and runs obliquely on the plantar aspect where it inserts on the base of the second MT. A “Lisfranc injury” describes a sprain to the Lisfranc ligament and can result in second MT dislocation.
“Lisfranc fractures” refer to fracture/subluxation of MTs. This can occur from MTs 2-5. (See Figure 2).
Figure 1 – Lisfranc Joint Complex Figure 2 – Lisfranc Fracture/dislocation
The injury is classified by 3 stages:
Stage 1: Lisfranc ligament sprain with no 2nd MT diastasis
Stage 2: Complete Lisfranc ligament rupture, 2-5 mm 2nd MT diastasis, no loss of medial arch height
Stage 3: Complete Lisfranc ligament rupture, 2-5 mm 2nd MT diastasis, loss of medial arch height
Injury Mechanism: Axial longitudinal force to the foot while plantar flexed and rotated
Figure 3 – Lisfranc Injury – foot being axially loaded
Differential Diagnoses:
Proximal 2nd MT fracture
Cuboid Fracture
Navicular Fracture
Posterior tibialis tendon rupture
Spring Ligament rupture
Exam:
Inspection: Inability to weight-bear (particularly with plantar flexed ankle), ecchymosis localized to plantar aspect of mid foot
Palpation: Tenderness along MT, pain with pronation and abduction of forefoot. In chronic injury, distraction of forefoot with rotation will reproduce pain and clicking in lisfranc.
Investigations:
X-ray: (Standing, AP, lateral, 30-degree oblique view)
1. Weight bearing X-ray: loss of alignment between the lateral edge of the 1st MT with the lateral edge of the medial cuneiform, loss of alignment between the medial edge of the 2nd MT with the medial edge of the intermediate cuneiform, and a “fleck sign” (small avulsed fragments).
2. Lateral X-ray: “step off sign” (dorsal surface of the proximal 2ndMT is superior to the dorsal surface of the medial cuneiform.
CT: May help classify and diagnose the injury, in addition to plan for surgical intervention.
Management:
Stage 1:Nonweightbearing fiberglass cast x 6 weeks. If pain free at 6 weeks, can remove cast, fit for custom orthotics, and begin graded return to activity. If pain present at 6 weeks: weightbearing ankle-foot orthotic for 4 weeks, followed by orthotics and graded return to activity.
Stage 2 and 3: Surgical management.
Dr. David W. Lawrence, May 19, 2014 (PR ND)
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