47 Midfoot Fractures and Dislocation (Lisfranc’s Injuries)
Midfoot fracture dislocations (Lisfranc’s injuries) represent a spectrum of injuries resulting in the disruption of the midfoot architecture. These injuries can range from subtle low-energy mechanisms and sprains to high-energy mechanisms such as motor vehicle collisions. Lisfranc’s injuries are often missed on initial evaluation and can result in midfoot destabilization and significant long-term disability. A well-performed physical examination, appropriate imaging, and a high index of suspicion are important for evaluation of these injuries. Subsequent treatment ranges from nonoperative management of subtle sprains to open reduction and internal fixation (ORIF) or primary arthrodesis for more significant injuries (▶Video 47.1).
History and physical examination
Mechanisms of injury:
Direct—force applied directly to the tarsometatarsal (TMT) joint.
i. Usually associated with significant soft-tissue injuries—MVCs, crush injury—more prone to compartment syndrome.
ii. Displacement related to direction of force (can be plantar or dorsal).
Indirect—twisting or axial loading on a plantar flexed foot—fall from height, athletic injuries. Dorsal displacement due to weaker dorsal ligaments versus plantar ligaments.
Can also occur due to atraumatic or repeated microtrauma in neuropathic patient, such as those with evidence of Charcot’s neuropathy.
i. Lisfranc’s equivalent: fractures of contiguous metatarsal bases.
ii. Tarsal fractures (cuboid/navicular fractures).
iii. Cuboid fractures: often associated with twisting mechanism. Nutcracker injury: cuboid fracture associated with Lisfranc’s injury when cuboid is fractured between the fourth and fifth metatarsals and calcaneus (▶ Fig. 47.1 ).
Inability to weight bear.
Tender along TMT joints.
Plantar arch ecchymosis.
i. Pain with passive pronation and abduction.
ii. Piano key test: dorsal force applied to forefoot while grasping metatarsal heads.
Lisfranc’s joint complex (▶ Fig. 47.2a ):
Plantar TMT ligaments—transverse instability with injury to ligament between medial cuneiform and the second/third metatarsal.
Dorsal TMT ligaments—weaker than plantar, displacement more often dorsal.
Intermetatarsal ligaments—no direction connection between the first and second metatarsals.
Lisfranc’sligament—lateral aspect of the medial cuneiform to medial base of the second metatarsal; tightens with pronation and forefoot abduction.
Role of the second metatarsal base (▶ Fig. 47.2b ):
Recessed proximally; forms mortise in medial and middle cuneiform.
Acts as keystone in Roman arch formation of metatarsal bases.
Dorsal pedis artery—runs between the first and second metatarsals; can be damaged during injury or repair.
Deep peroneal nerve—can become interposed during reduction maneuver.
Anterior tibial tendon—inserts into the first metatarsal base and medial cuneiform; can obstruct reductions of lateral dislocations.
Peroneus longus tendon—inserts into the plantar aspect of the first metatarsal base.
Interossei/plantar fascia—provides additional plantar support.
Anteroposterior (AP), lateral, and oblique X-rays: 20% go unrecognized:
AP—best for the first and second TMT joints.
Oblique—best for the third, fourth, and fifth TMT joints.
Best if weight bearing.
i. If clinical suspicion remains, obtain comparison films of the contralateral foot.
ii. Many times, a patient cannot bear weight the day of injury due to pain. Repeat weight bearing films the following week may be helpful in these circumstances.
X-ray assessment for midfoot stability:
AP view (▶ Fig. 47.3a ):
i. Up to 3 mm between the first and second metatarsal bases.
ii. Lateral base of the first metatarsal in line with the lateral aspect of the medial cuneiform.
iii. Medial base of the second metatarsal in line with the medial aspect of the middle cuneiform.
Oblique view (▶ Fig. 47.3b ):
i. Medial base of the third metatarsal is in line with the medial aspect of the lateral cuneiform.
ii. Medial base of the fourth metatarsal is in line with the medial aspect of the cuboid.
Lateral view (▶ Fig. 47.3c ): The metatarsal is in line with the tarsal bone (no dorsal subluxation).
Other radiographic signs:
Second metatarsal base fractures.
Widening of the first intermetatarsal space (check contralateral limb for asymmetry): best if films are weight bearing (▶ Fig. 47.4 ).
“Fleck sign”—avulsion of Lisfranc’s ligament (▶ Fig. 47.5a ).
CT—high-energy or for preoperative planning.
MRI—rarely useful, but can be utilized if other imaging is negative and clinical suspicion remains.
Classifications: have not been determined to have prognostic value
Quenu and Kuss (modified by Hardcastle):
Homolateral—all five metatarsals displaced in one direction (typically laterally).
Isolated—one or two metatarsals displaced.
Divergent—the first metatarsal displaced medially and the second to fifth metatarsals displaced laterally. There is displacement in both the sagittal and coronal planes.