Cortical suspensory button fixation has superior biomechanical properties to knotless anchor suture in anterior cruciate ligament repair: a biomechanical study

The purpose of our biomechanical study was to assess load-to-failure, stiffness, gap formation following cyclic loading, and the failure mechanism for anterior cruciate ligament (ACL) repair comparing the cortical suspensory button and knotless anchor suture. Eight Thiel’s embalmed paired cadaveric knees from four cadavers were dissected. The specimens were assigned to undergo ACL repair either with cortical suspensory button or with knotless anchor suture. The Instron machine replicates cyclic loading and then determines the gap formation. Traction was applied until failure. The load-to-failure, stiffness, and modes of failure in both groups were recorded. The load-to-failure, stiffness, and gap formation were compared between the two groups using the student's t-test. The mean load-to-failure in the cortical suspensory button group was significantly higher than the knotless anchor suture group (212.96 ± 54.57 vs 44.57 ± 20.80, p value < 0.01). No statistically significant difference was found regarding gap formation following cyclic loading and stiffness between the cortical suspensory button group and the knotless anchor suture group. This biomechanical study showed a higher load-to-failure for the ACL repair with cortical suspensory button compared to ACL repair with knotless anchor suture, while no statistically significant difference was found regarding the gap formation following cyclic loading and the stiffness. The load-to-failure in both cortical suspensory button and knotless anchor suture are below regular daily activity load. Thus, an internal brace or external support is recommended during rehabilitation.