Biomechanical analysis of endobutton versus screw fixation after Lisfranc ligament complex sectioning

BackgroundOur goal was to compare diastasis after endobutton and screw fixation after Lisfranc ligament complex sectioning.MethodsTwenty-four (12 pairs) fresh-frozen cadaveric feet were assigned to endobutton or screw fixation and loaded to 343 N. Displacement (first–second metatarsal bases) was measured in intact feet and after ligament sectioning (Lisfranc, medial–intermediate cuneiform ligaments), fixation, and 10,000 cycles.ResultsThe mean change in diastasis for endobutton and screw fixation under initial loading was 1.0 mm (95% CI, 0.2–1.9 mm) and 0.0 mm (95% CI, −0.4 to 0.4 mm), respectively (p = 0.017). After cyclic loading, diastasis decreased (mean, −0.7 mm, 95% CI, −1.2 to −0.1 mm) in the endobutton group but was unchanged in the screw group (p = 0.035).ConclusionsDiastasis after endobutton fixation was significantly greater than after screw fixation under initial loading but did not increase further after cyclic loading.