Duke Sports Science Institute, Department of Orthopaedic Surgery, Duke University School of Medicine, Durham, North Carolina, USA.
Department of Mechanical Engineering, Duke University, Durham, North Carolina, USA.
Am J Sports Med. 2018 Jul;46(8):1857-1862. doi: 10.1177/0363546518771365. Epub 2018 May 15.
Adjustable-loop cortical buttons for femoral fixation of bone-tendon-bone grafts have potential advantages over interference screw fixation; however, these devices have not been benchmarked biomechanically against interference screws. Purpose/Hypothesis: The purpose was to compare the time zero biomechanical properties of commercially available, adjustable-loop cortical button and metallic interference screws for femoral fixation of bone-tendon-bone grafts. It was hypothesized that no significant differences would be found in biomechanical properties between fixation techniques.
Controlled laboratory study.
Adjustable-loop cortical buttons (n = 8) and metallic interference screws (n = 8) were used to fix matched pairs of human bone-tendon-bone allografts in porcine distal femurs. These constructs were preconditioned (10 N to 50 N at 1 Hz, 10 cycles), subjected to cyclic loading (50 N to 250 N at 1 Hz, 500 cycles), and then pulled to failure at 20 mm/min.
The loads to failure (mean ± SD, 700 ± 256 N vs 688 ± 215 N, P = .92) and linear stiffnesses (219 ± 48 N/mm vs 218 ± 49 N/mm, P = .97) for the adjustable-loop cortical button and metallic interference screws, respectively, were not significantly different. Cyclic displacement was higher in the adjustable-loop cortical button group (2.1 ± 0.6 mm vs 1.3 ± 0.4 mm, P = .01). The mechanism of failure was different between groups, with bone block slippage occurring most commonly in the interference screw group (n = 5) and fracture of the bone block through the suture hole occurring most commonly in the adjustable-loop cortical button group (n = 6).
Adjustable-loop cortical buttons and interference screws have similar time zero failure loads, although cyclic displacement was higher with the adjustable-loop cortical buttons. The mean difference in displacement was less than 1 mm compared with the interference screw.
Adjustable-loop cortical buttons may be an acceptable alternative to an interference screw for femoral fixation of bone-tendon-bone grafts in anterior cruciate ligament reconstruction. The clinical relevance of the observed differences in cyclic displacement is unknown and should be evaluated in future studies.
可调环皮质按钮用于固定骨-腱-骨移植物的股骨固定具有潜在优势，优于干扰螺钉固定；然而，这些装置尚未与干扰螺钉进行生物力学基准测试。目的/假设：目的是比较商业上可用的可调环皮质按钮和金属干扰螺钉在固定骨-腱-骨移植物的股骨固定方面的零时间生物力学特性。假设在固定技术之间不会发现生物力学特性的显着差异。
对照实验室研究。
使用可调环皮质按钮（n = 8）和金属干扰螺钉（n = 8）固定匹配的人骨-腱-骨同种异体移植物在猪的股骨远端。这些结构经过预处理（1 Hz 时 10 N 至 50 N，10 个循环），进行循环加载（1 Hz 时 50 N 至 250 N，500 个循环），然后以 20 mm/min 的速度拉断。
可调环皮质按钮和金属干扰螺钉的失效载荷（平均值±标准差，700 ± 256 N 与 688 ± 215 N，P =.92）和线性刚度（219 ± 48 N/mm 与 218 ± 49 N/mm，P =.97）差异无统计学意义。可调环皮质按钮组的循环位移更高（2.1 ± 0.6 mm 与 1.3 ± 0.4 mm，P =.01）。两组的失效机制不同，干扰螺钉组最常见的是骨块滑移（n = 5），可调环皮质按钮组最常见的是骨块穿过缝线孔断裂（n = 6）。
可调环皮质按钮和干扰螺钉具有相似的零时间失效载荷，尽管可调环皮质按钮的循环位移更高。与干扰螺钉相比，位移的平均差异小于 1 毫米。
可调环皮质按钮可能是前交叉韧带重建中骨-腱-骨移植物股骨固定的可接受替代物干扰螺钉。观察到的循环位移差异的临床相关性尚不清楚，应在未来的研究中进行评估。
