Division of Sports Medicine, Department of Orthopedic Surgery, Rush University Medical Center, Rush Medical College of Rush University, Chicago, Illinois 60612, USA.
Arthroscopy. 2011 Feb;27(2):161-6. doi: 10.1016/j.arthro.2010.07.004. Epub 2010 Oct 27.
To evaluate the effect of screw length and diameter on the mechanical properties of biceps tenodesis (BT) with an interference screw in 2 different locations (proximal and distal).
We randomized 42 fresh-frozen human cadaveric shoulders (mean age, 65 ± 8 years) into 6 groups (n = 7): arthroscopic proximal BT using 7 × 15-, 7 × 25-, 8 × 15-, or 8 × 25-mm interference screws or distal subpectoral BT with 7 × 15- or 8 × 15-mm interference screws. Each repaired specimen was mounted onto a materials testing machine, preloaded to 5 N for 2 minutes, cycled from 5 to 70 N for 500 cycles (1 Hz), and loaded to failure (1 mm/s). Displacement during cyclical loading, pullout stiffness, and ultimate load to failure were computed, and the mechanism of failure was noted.
All failures occurred at the tendon-screw interface. There was no statistically significant difference in ultimate displacement among all groups in the ultimate load to failure, displacement at peak load, and stiffness.
There is no difference in ultimate load to failure, displacement at peak load, and stiffness of BT with regard to screw length or diameter at both proximal and distal tenodesis locations. These data would support use of a smaller-diameter and shorter implant for BT both proximally and distally.
The results may serve as a guide to the orthopaedic surgeon performing proximal BT in selecting the appropriate interference screw. When possible, we recommend using the smallest screw size available to minimize risk of stress fracture at the tenodesis site.
评估在肱二头肌肌腱固定术（BT）中使用不同长度和直径的螺钉在两个不同位置（近端和远端）对力学性能的影响。
我们将 42 个新鲜冷冻的人体尸体肩关节随机分为 6 组（n = 7）：关节镜下近端 BT 使用 7×15、7×25、8×15 或 8×25mm 干扰螺钉，或远端胸肌下 BT 使用 7×15 或 8×15mm 干扰螺钉。每个修复标本都安装在材料试验机上，预加载 5N 持续 2 分钟，循环从 5N 到 70N 进行 500 次（1Hz），并以 1mm/s 的速度加载至失效。计算循环加载过程中的位移、拔出刚度和失效时的极限载荷，并记录失效机制。
所有失效均发生在肌腱-螺钉界面。在失效时的极限载荷、峰值载荷时的位移和刚度方面，所有组之间的最终位移均无统计学差异。
在近端和远端肌腱固定术位置，螺钉长度或直径对 BT 的失效时的极限载荷、峰值载荷时的位移和刚度均无差异。这些数据将支持在近端和远端都使用较小直径和较短的植入物进行 BT。
这些结果可以为进行近端 BT 的骨科医生选择合适的干扰螺钉提供指导。在可能的情况下，我们建议使用最小尺寸的螺钉，以最大程度地降低肌腱固定部位的应力性骨折风险。
