Mesfar W, Shirazi-Adl A
Laboratory of Biomechanical Orthopedics, Ecole Polytechnique Fédérale de Lausanne, Switzerland.
Clin Biomech (Bristol). 2008 May;23(4):477-82. doi: 10.1016/j.clinbiomech.2007.11.016. Epub 2008 Jan 4.
Different rehabilitation exercises such as open-kinetic-chain flexion and extension exercises are currently employed in non-operative and post-operative managements of joint disorders. The challenge is to strengthen the muscles and to restore the near-normal function of the joint while protecting its components (e.g., the reconstructed ligament) from excessive stresses.
Using a validated 3D nonlinear finite element model, the detailed biomechanics of the entire joint in open-kinetic-chain flexion exercises are investigated at 0 degrees, 30 degrees, 60 degrees and 90 degrees joint angles. Two loading cases are simulated; one with only the weight of the leg and the foot while the second considers also a moderate resistant force of 30 N acting at the ankle perpendicular to the tibia.
The addition of 30 N resistant force substantially increased the required hamstrings forces, forces in posterior cruciate and lateral collateral ligaments and joint contact forces/areas/stresses.
At post-anterior cruciate ligament reconstruction or injury period, the exercise could safely be employed to strengthen the hamstrings muscles without a risk to the anterior cruciate ligament. In contrast, at post-posterior cruciate/lateral collateral ligaments reconstructions or injuries, the open-kinetic-chain flexion exercise should be avoided under moderate to large flexion angles and resistant forces.
目前，诸如开链屈伸练习等不同的康复锻炼方法被用于关节疾病的非手术和术后管理。挑战在于增强肌肉力量并恢复关节的近乎正常的功能，同时保护其组成部分（例如重建的韧带）免受过度应力的影响。
使用经过验证的三维非线性有限元模型，研究在关节角度为0度、30度、60度和90度时开链屈伸练习中整个关节的详细生物力学情况。模拟了两种加载情况；一种仅考虑腿部和足部的重量，另一种还考虑了作用于脚踝且垂直于胫骨的30 N的中等阻力。
增加30 N的阻力显著增加了所需的腘绳肌力量、后交叉韧带和外侧副韧带中的力量以及关节接触力/面积/应力。
在前交叉韧带重建或损伤后阶段，可以安全地进行该锻炼以增强腘绳肌力量，而不会对前交叉韧带造成风险。相比之下，在后交叉韧带/外侧副韧带重建或损伤后阶段，在中等至大的屈曲角度和阻力下应避免进行开链屈伸练习。
