Analysis of the functional adaptation of biological tissues and its application to mechanical design

我们一直在研究肌腱和韧带在不同结构水平上对机械环境的适应性。在本研究中，考虑到前交叉韧带（ACL）和后交叉韧带（PCL）施加应力的位置依赖性，前-后抽屉载荷下的韧带中的载荷分布和它们的力学性能之间的关系，确定在不同的屈曲角度。结果表明：（1）前交叉韧带（ACL）前交叉韧带所承受的载荷取决于前交叉韧带的屈曲角度和韧带束。在伸展时，后外侧（Pl）束比前内侧（AM）部分承载更多的载荷。随着屈曲角度的增加，前屈部承受的载荷增加，后屈部承受的载荷减少。前交叉韧带的力学性能与前交叉韧带的屈曲角度和韧带束有关。随着屈曲角度的增加，韧带束的刚度增加。2）PCL韧带的力学性能和承载力均依赖于韧带束。前外侧束总是进行了相当大的负载，而束的刚度总是很大。这些研究结果表明，在不同的屈曲角度的交叉韧带的力学性能的分布对应的负载分布。这表明，膝关节的设计是最佳的，使其韧带功能最有效地在特定的屈曲角度，和外部和内部负载的膝盖保持最佳的结构和性能的一致性。这是可能的，这种机制可以应用到一种新的机械设计的发展。

We have been studying adaptation of tendons and ligaments to mechanical environments at various structure levels. In the present study, considering a locational dependence of applied stress to the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL), a relationship between the load distribution in the ligaments under anterior-posterior drawer load and their mechanical properties was determined at different flexion angles. The following findings were obtained.1) ACLThe load carried by the ACL depended on both the flexion angle and ligament bundle. In extension, the posterolateral (Pl) bundle carried more load than the anteromedial (AM) portion did. As the flexion angle increased, the load carried by the AM portion icreased while that carried the PL portion decreased. The mechanical property of the ACL was also dependent on both the flexion angle and ligament bundle. As the flexion angle increased, the stiffness of the PL bundle increased.2) PCLBoth the load carried by the PCL and the mechanical property of the PCL were dependent on the ligament bundle. The anterolateral bundle always carried a considerable load, while the stiffness of the bundle was always great.These findings indicate that the load distribution corresponds to the distribution of mechanical properties in the cruciate ligaments at different flexion angles. This suggests that the knee joint is optimally designed so that its ligaments function most effectively at specific flexion angles, and that the external and internal loading to the knee maintains the uniformity of the optimal structure and property. It is possible that this mechanism could be applied to the development of a novel mechanical design.