Stabilization of Lisfranc joint injuries: a biomechanical study

Lisfranc joint injuries are often misdiagnosed, leading to significant morbidity. Methods for anatomic reduction of the tarsometatarsal joint include closed reduction with casting or surgical stabilization with either Kirschner wires and/or cortical screw fixation. Controversy exists as to which fixation technique offers optimal stability. In the present study, the biomechanical stability of three fixation methods was tested: (1) four Kirschner wires, (2) three cortical screws plus two Kirschner wires, and (3) five cortical screws.

Ten matched pairs of fresh-frozen cadaveric feet were dissected to their ligamentous and capsular elements. The tarsometatarsal ligaments were completely transected to replicate a Lisfranc dislocation; the "injury" was reduced and stabilized using one of the three methods. Biomechanical studies were performed by applying a 100-N cyclic load physiologically distributed to the plantar aspect of the metatarsal heads. Displacement and force measurements were taken from the first and fifth metatarsal heads. Average stiffness of each construct was calculated from the force displacement curves.

Method 2 provided significantly more stability than Kirschner wire fixation. Method 3 created more stiffness than method 2 at the medial portion of the foot; no statistical difference between the two methods was evident at the lateral foot.

Cortical screw fixation provides a more rigid and stable method of fixation for Lisfranc injuries as compared to Kirschner wire fixation. This fixation method allows maintenance of anatomic reduction and possibly earlier mobilization with a decreased risk of posttraumatic arthrosis.