Fixação do enxerto do ligamento cruzado anterior no polo tibial: Análise biomecânica de três métodos

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.

Biomechanical comparison of anterior cruciate ligament reconstruction fixation methods and implications on clinical outcomes

“…Post fixation is another method of ACLR, which is usually a metal screw, with or without a washer, or a cross pin that acts as a stable, inflexible point of fixation in the bone separate from the tunnel aperture that acts as a point of fixation for the graft. Post methods of fixation allow for cortical fixation of the graft to the bone often through the use of sutures as an intermediary ( 12 ). Table 4 depicts the studies that include post fixation.…”

“…Table 4 depicts the studies that include post fixation. When analyzing tibial sided graft fixation techniques, Weiss et al ( 12 ) compared IFS fixation, screw-post and washer fixation, and screw-post and washer fixation with an additional IFS in an ACLR animal model. In their analysis, the hybrid fixation of a post and IFS yielded significantly higher final stiffness and higher yield load than the other fixation methods.…”

“…As such, hybrid fixation methods have been explored to determine if adjunct fixation improves graft stiffness and increase the fixation strength of the construct. Specifically, hybrid fixation has been used to address concerns with tibial fixation, as the tibia has lower bone density than the femur, and the graft is subject to slippage with parallel fixation ( 2 , 7 , 12 ). Multiple studies have found that suspensory fixation combined with an IFS fixation is biomechanically superior to suspensory fixation alone ( 41 , 42 ).…”

“…In a porcine model, Walsh et al ( 42 ) demonstrated that soft tissue grafts fixed with an IFS and suspensory cortical button were able to withstand higher initial and ultimate loads to failure. Similarly, hybrid fixation of an IFS with a post has also been shown to be biomechanically superior ( 12 ).…”

“…Regardless of the implant chosen for fixation, secure fixation is paramount to avoid displacement of the graft and allow for graft integration into the bone tunnel, which typically occurs around three months after surgery ( 2 ). Therefore, the biomechanical properties of these implants are particularly important in facilitating early post-operative rehabilitation after ACLR that is necessary for a successful clinical outcome, while also withstanding the shear and tensile forces to avoid displacement and early graft failure during graft osseointegration ( 12 ).…”