Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
Funabashi Orthopaedic Hospital, Chiba, Japan.
J Shoulder Elbow Surg. 2021 Feb;30(2):359-364. doi: 10.1016/j.jse.2020.05.033. Epub 2020 Jun 18.
The ulnar collateral ligament complex, particularly the anterior oblique ligament (AOL), is mainly a static stabilizer controlling valgus. Various studies have been conducted on the kinematics of elbow joints after ligament cutting; however, no biomechanical studies have measured the tension applied to the ligament. Finite element modeling (FEM) is a very useful tool for biomechanical evaluation of the elbow. However, an accurate FEM of elbow joints cannot be developed without information on the potential tension of ligaments applied during the flexion and extension of elbow joints. We believe that FEM of the elbow joint could be obtained by measuring the material properties and potential tension of the ligament applied during the flexion and extension of the elbow joint. This study aimed to measure the potential tension and material properties of the ligament during the flexion and extension of the elbow, by identifying the relation between ligament length and tension using mechanical testing.
We included 10 elbows harvested from 7 fresh-frozen cadavers. The average age of the cadavers was 83.7 ± 5.65 years, and the samples included 8 elbows from 6 male cadavers and 2 elbows from 1 female cadaver. We measured the ligament length at each elbow angle by changing the elbow joint from 0° to 120° in 15° intervals. Thereafter, we extracted the AOL and divided into an anterior band (AB) and a posterior band (PB) and performed a mechanical test to calculate ligament stress.
The ligament length of the AB gradually decreased as the flexion angle increased. Conversely, the ligament length of the PB gradually increased as the flexion angle increased. AB and PB lengths were approximately the same between 60° and 75°. The average ligament tension and stress of the AB gradually increased with elbow extension. In contrast, the average ligament tension and stress of the PB gradually increased with elbow flexion. The tension and stress of the AB and PB were balanced around the elbow joint at 60°.
The AB was tenser on elbow extension, and the PB was tenser following elbow flexion. Also, the angle at which the AOL stress was equalized was 60°, suggesting that ∼60° is the angle at which the AOL is unlikely to be damaged.
尺侧副韧带复合体，特别是前斜韧带（AOL），主要是控制外翻的静态稳定器。已经有许多关于韧带切断后肘关节运动学的研究，但没有生物力学研究测量韧带所施加的张力。有限元建模（FEM）是评估肘部生物力学的非常有用的工具。然而，如果没有关于在肘关节屈伸过程中韧带潜在张力的信息，就无法开发出准确的肘部 FEM。我们认为，可以通过测量在肘关节屈伸过程中应用的韧带的材料特性和潜在张力来获得肘关节的 FEM。本研究旨在通过使用机械测试来确定韧带长度与张力之间的关系，来测量在肘关节屈伸过程中韧带的潜在张力和材料特性。
我们纳入了 10 个来自 7 个新鲜冷冻尸体的肘部。尸体的平均年龄为 83.7±5.65 岁，样本包括 6 个男性尸体的 8 个肘部和 1 个女性尸体的 2 个肘部。我们通过将肘关节从 0°改变到 120°，每隔 15°测量一次每个肘部角度的韧带长度。然后，我们提取 AOL 并将其分为前带（AB）和后带（PB），并进行机械测试以计算韧带应力。
AB 的韧带长度随着屈曲角度的增加而逐渐减小。相反，PB 的韧带长度随着屈曲角度的增加而逐渐增加。AB 和 PB 的长度在 60°至 75°之间大致相同。AB 的平均韧带张力和应力随着肘关节伸展而逐渐增加。相比之下，PB 的平均韧带张力和应力随着肘关节弯曲而逐渐增加。AB 和 PB 的张力和应力在 60°的肘部平衡。
AB 在肘关节伸展时更紧张，PB 在肘关节弯曲时更紧张。此外，AOL 应力平衡的角度为 60°，这表明大约 60°是 AOL 不太可能受损的角度。
