Fixation of the Anterior Ligament Graft at the Tibial Pole: Biomechanical Analysis of Three Methods

Abstract

Objective :Comparative biomechanical analysis of tibial fixation strength for ligament reconstruction with interference screw compared with screw post and washer, and compared with the associated fixation of both methods (hybrid fixation). Method :A total of 54 specimens were used (porcine tibias and bovine flexor digital tendons), which were divided into three groups with fixation types similar to those used in anterior cruciate ligament (ACL) reconstruction: 1) fixation with interference screw; 2) fixation with screw post and toothed washer over knot and suture strand; and)- fixation with screw post and washer combined with interference screw (hybrid fixation). The analyses were performed through pull-out biomechanical tensile tests to determine the stiffness and load to system failure (yield load). Results :The hybrid fixation group presented a significantly higher final stiffness (59.10 ± 3.45 N/mm) in comparison to the other groups (p < 0.05) and a higher yield load (581.34 ± 33.48 N) compared to the interference screw group (p < 0.05). Conclusion :Hybrid fixation had biomechanical advantages over the bovine digital flexor graft fixation system in swine tibia during tensile tests.