Biomechanical analysis of a double fixation method for tendon graft in porcine tibia - using an interference screw plus staple

ABSTRACT Objective: The aim of the study was to compare the mechanical behavior of interference screw tibial fixation vs. screw-plus-staple tibial fixation in an animal model. Methods: Thirty-six pieces of swine knee specimens were selected and divided into two groups: Group 1, tibial fixation with interference screw (n = 17), and Group 2, fixation with interference screw and staple (n = 19). The models were submitted to a single cycle of tension testing. The following variables were measured: graft cross-sectional area, failure point on 10 mm (F10), yield load (Fy), and stiffness. Results: The mean values of graft cross-sectional area, F10, Fy, and stiffness did not present significant differences between the groups. Conclusion: The addition of a second staple-type ligament fixation device, complementing the interference screw, did not increase the mechanical safety of the system.