The Use of Knotless Fiber Tape Construct vs Screw Fixation for Lisfranc Injuries: A Cadaveric Biomechanical Study

Category: Trauma; Midfoot/Forefoot Introduction/Purpose: Lisfranc injuries are often treated with open reduction and internal fixation using rigid fixation techniques. The use of flexible fixation to stabilize the Lisfranc joint is a newer technique. The purpose of this cadaveric study is to compare the amount of diastasis at the Lisfranc interval under physiologic loads when treated with a knotless fiber tape construct and a solid screw. Methods: Ten cadavers (20 feet) had native motion at the intact Lisfranc interval assessed at multiple physiologic loads representing guarded walking (69N), walking (138N), and running (207N). The Lisfranc ligamentous complex was then disrupted, and testing repeated to evaluate the amount of diastasis. Randomization was performed to determine type of fixation for each cadaver: a solid screw or knotless fiber tape construct. Once fixation was completed, specimens were cyclically loaded for 10,000 cycles at physiologic loads and diastasis was quantified after each load cycle to compare the interventions. Diastasis was measured using motion tracking cameras and retroreflective marker sets. A non-inferiority statistical analysis was performed. Results: Diastasis mean values were confirmed to be >2mm for all load bearing conditions in the injury model. Post-treatment, diastasis was significantly reduced when compared to the sectioned conditions (p=0.00) for both treatment options. Non-inferiority analyses showed that the knotless fiber tape construct did not perform inferior to screw fixation for diastasis at the Lisfranc interval at any of the compared load states. Conclusion: Under physiologic loads, there is no significant difference in diastasis at the Lisfranc interval when treating ligamentous Lisfranc injuries with a knotless fiber tape construct or solid screws. Both reduced diastasis from the injured state and were not different from the intact state.