While stabilizing the rearfoot, apply an adductory/supinatory force on the lateral aspect around the fifth metatarsal base, then an abductory/pronatory force near the first metatarsal base (Fig. 116.4).
Each metatarsal base is stressed in a dorsal and plantar direction while grabbing the metatarsal head, which has been previously called the “piano key test” (9). Excessive movement especially dorsally is positive for disruption of the joint.
On the anteroposterior view, the metatarsal bases should line up with their corresponding cuneiforms and the cuboid. A gap greater than 2 mm between the medial and intermediate cuneiform may signify an injury. A “fleck fracture” or “fleck sign” may be evident at the medial base of the second metatarsal and is caused by traction of the Lisfranc ligament (Fig. 116.6A).
On the medial oblique view, the medial aspect of the fourth metatarsal aligns with the corresponding border of the cuboid (Fig. 116.6B).
compared with the other side when no other disruption is identified. This rule can be applied to any questionable pathology but seems to be utilized more in trauma cases. Probably the number one instance, however, is in pediatric cases comparing physes.
TABLE 116.1 Lisfranc Classifications
the dislocation is obvious and not reduced upon presentation, a CT scan could be considered superfluous. When the injury is suspected but not readily identified on plain films, then a CT scan can be ordered (Fig. 116.7). Surgeon preference may dictate CT usage in both scenarios to ascertain the osseous integrity and degree of communition of the metatarsal bases for fixation or fusion. A CT scan may also demonstrate other subtle fractures of the midfoot. The author routinely orders CT scans for Lisfranc injuries. An MRI can also be ordered but rarely (17,18).
These injuries may present open, which then initiates the Gustilo-Anderson open fracture classification and protocol (19).
The clinical presentation and mechanism of injury can lead to a compartment syndrome. The most important phrase “index of suspicion” then has to take hold and compartment pressures measured (20). Then two injuries are managed: the fracture dislocation (and other fractures if present) along with the compartment syndrome (Fig. 116.8). The latter is a surgical emergency.
compartment syndrome. A salient question: is the foot pulseless because of the dislocation? If so, then the dislocation needs to be reduced to reestablish blood flow. Maneuvers for this could require the operating room, especially if an initial attempt fails. Keep the “attempts” to one, two at most. Too many can lead not only to damage of the soft tissues but osseous structures as well. Failure to establish blood flow necessitates immediate surgical intervention. Fasciotomies are performed for neurovascular compromise in the presence of a compartment syndrome.