Utilizing supplementary high-strength suture tying over a bone bridge enhances the effectiveness of interference screw as tibial fixation method in anterior cruciate ligament reconstruction.

Abstract

Background: Tibial fixation is the biomechanical weak point in anterior cruciate ligament (ACL) reconstruction, with numerous techniques proposed to address this challenge. This study evaluates the utility of a simple, cost-effective system: high-strength suture tying over a bone bridge (BB). Its effectiveness as standalone fixation and as a supplement to standard interference screw (IS) fixation is compared with IS alone and supplemented with other commercial systems.

Methods: A biomechanical study was conducted using six fixation methods tested on 61 specimens with bovine extensor tendons in porcine tibial models. Groups included BB alone, IS alone, and four hybrid fixation methods: IS + BB, IS + a cortical screw post (CSP), IS + a PushLock^® anchor, and IS + a SwiveLock^® anchor, with at least nine specimens per group. Specimens underwent cyclic load testing (500 cycles at 100-200 N) and pull-to-failure tests (20 mm/min) to measure displacement, ultimate load to failure, and stiffness.

Results: Standalone BB fixation showed limited performance, with an ultimate load to failure of 357.81 ± 90.53 N and cyclic displacement of 14.88 ± 3.28 mm, insufficient for early rehabilitation. When combined with IS, BB significantly improved performance, achieving an ultimate load to failure of 500.55 ± 151.24 N, comparable to commercial systems, and reducing cyclic displacement to 4.82 ± 0.83 mm. Hybrid fixation methods lowered early failure rates to 10%, compared with 30-40% in single-method fixations, confirming enhanced stability.

Conclusions: Hybrid fixation methods are more reliable than simple ones for tibial fixation. Combining IS with BB provides a biomechanically robust and cost-effective solution for ACL reconstruction. This simple, ecological and affordable method reduces early failure rates, minimizes cyclic displacement, and achieves outcomes comparable to commercial systems, offering a practical choice for improving ACL repair outcomes.