Computational analysis of Lisfranc surgical repairs.

Ligamentous Lisfranc injuries cause debilitating pain and loss of function. Even small diastasis of this normally rigid joint after injury requires surgical treatment, but outcomes remain poor. Existing literature has compared the different surgical procedures using cadaveric models, but no approach has been recommended over others. This study uses a computational biomechanical approach consistent with a cadaveric study to evaluate the different procedures' ability to stabilize the Lisfranc joint without inducing secondary consequences. A validated rigid body model for the cadaver foot with a Lisfranc injury was extended to compare the stability of four different surgical repairs-three open reduction and internal fixation procedures with different hardware (cannulated screws, endobuttons, and screws with a dorsal plate) and primary arthrodesis with screws. Forces calculated from the rigid body model for 50% partial weight bearing provided boundary conditions for a finite element model of the surgical repairs. Comparing the different surgical procedures, the open reduction and internal fixation with screws and primary arthrodesis with screws showed the most stable postoperative Lisfranc joint. However, the use of cannulated screws for fixation showed regions of high stress that may be susceptible to breakage and also resulted in higher contact forces in joints adjacent to the surgery site. Endobuttons and dorsal plates did not restore sufficient stability. Since all procedures showed different points of concern that could impact outcomes, additional surgical approaches could be needed in the future. This study offers a standard protocol for benchmarking the new procedures against those currently used.