Ahmed A M, McLean C
McGill University, Department of Mechanical Engineering, 817 Sherbrooke St. West, Montreal, Quebec, Canada H3A 2K6.
J Biomech Eng. 2002 Dec;124(6):768-79. doi: 10.1115/1.1504100.
The study aimed to test the hypothesis that the restraining role of the anterior cruciate ligament (ACL) of the knee is significant during the activities of normal walking and stair ascent. The role of the ACL was determined from the effect of ACL excision on tibiofemoral displacement patterns measured in vitro for fresh-frozen knee specimens subjected to simulated knee kinetics of walking (n = 12) and stair ascent (n = 7). The knee kinetics were simulated using a newly developed dynamic simulator able to replicate the sagittal-plane knee kinetics with reasonable accuracy while ensuring unconstrained tibiofemoral kinematics. The displacements were measured using a calibrated six degree-of-freedom electromechanical goniometer. For the simulation of the walking cycle, two types of knee flexion/extension moment patterns were used: the more common "biphasic" pattern, and an extensor muscle force intensive pattern. For both of these patterns, the restraining role of the ACL to tibial anterior translation was found to be significant throughout the stance phase and in the terminal swing phase, when the knee angle was in the range of 4 degrees to 30 degrees. The effect of ACL excision was an increase in tibial anterior translation by 4 mm to 5 mm. For the stair ascent cycle, however, the restraining role of the ACL was significant only during the terminal stance phase, and not during the initial and middle segments of the phase. Although, in these segments, the knee moments were comparable to that in walking, the knee angle was in the range of 60 degrees to 70 degrees. These results have been shown to be consistent with available data on knee mechanics and ACL function measured under static loading conditions.
在正常行走和上楼梯活动期间，膝关节前交叉韧带（ACL）的限制作用显著。通过对新鲜冷冻膝关节标本进行体外测量，观察ACL切除对胫股位移模式的影响，从而确定ACL的作用。这些标本模拟了行走（n = 12）和上楼梯（n = 7）的膝关节动力学。使用新开发的动态模拟器模拟膝关节动力学，该模拟器能够以合理的精度复制矢状面膝关节动力学，同时确保胫股运动不受限制。使用校准的六自由度电动测角仪测量位移。对于步行周期的模拟，使用了两种类型的膝关节屈伸力矩模式：较常见的“双相”模式和伸肌肌力增强模式。对于这两种模式，在整个站立期和终末摆动期，当膝关节角度在4度至30度范围内时，发现ACL对胫骨前移的限制作用显著。ACL切除的影响是胫骨前移增加4毫米至5毫米。然而，对于上楼梯周期，ACL的限制作用仅在终末站立期显著，而在该阶段的初始和中间段不显著。尽管在这些阶段，膝关节力矩与行走时相当，但膝关节角度在60度至70度范围内。这些结果已被证明与在静态加载条件下测量的膝关节力学和ACL功能的现有数据一致。
