Potvin Brigitte M, Shourijeh Mohammad S, Smale Kenneth B, Benoit Daniel L
Department of Mechanical Engineering, University of Ottawa, Ottawa, Ontario, Canada.
Department of Mechanical Engineering, University of Ottawa, Ottawa, Ontario, Canada; School of Rehabilitation Sciences, University of Ottawa, Ottawa, Ontario, Canada.
J Biomech. 2017 Sep 6;62:124-131. doi: 10.1016/j.jbiomech.2017.02.006. Epub 2017 Feb 21.
Musculoskeletal modeling and simulations have vast potential in clinical and research fields, but face various challenges in representing the complexities of the human body. Soft tissue artifact from skin-mounted markers may lead to non-physiological representation of joint motions being used as inputs to models in simulations. To address this, we have developed adaptive joint constraints on five of the six degree of freedom of the knee joint based on in vivo tibiofemoral joint motions recorded during walking, hopping and cutting motions from subjects instrumented with intra-cortical pins inserted into their tibia and femur. The constraint boundaries vary as a function of knee flexion angle and were tested on four whole-body models including four to six knee degrees of freedom. A musculoskeletal model developed in OpenSim simulation software was constrained to these in vivo boundaries during level gait and inverse kinematics and dynamics were then resolved. Statistical parametric mapping indicated significant differences (p<0.05) in kinematics between bone pin constrained and unconstrained model conditions, notably in knee translations, while hip and ankle flexion/extension angles were also affected, indicating the error at the knee propagates to surrounding joints. These changes to hip, knee, and ankle kinematics led to measurable changes in hip and knee transverse plane moments, and knee frontal plane moments and forces. Since knee flexion angle can be validly represented using skin mounted markers, our tool uses this reliable measure to guide the five other degrees of freedom at the knee and provide a more valid representation of the kinematics for these degrees of freedom.
肌肉骨骼建模与模拟在临床和研究领域具有巨大潜力，但在呈现人体复杂性方面面临各种挑战。来自皮肤表面标记物的软组织伪影可能导致关节运动的非生理性表征，而这些表征被用作模拟模型的输入。为解决这一问题，我们基于在步行、单脚跳和切入动作过程中记录的体内胫股关节运动，为膝关节六个自由度中的五个开发了自适应关节约束，这些运动来自于在胫骨和股骨中插入皮质内针的受试者。约束边界随膝关节屈曲角度而变化，并在包括四到六个膝关节自由度的四个全身模型上进行了测试。在OpenSim模拟软件中开发的肌肉骨骼模型在水平步态期间被约束到这些体内边界，然后求解逆运动学和动力学。统计参数映射表明，在骨针约束和无约束模型条件下，运动学存在显著差异（p<0.05），尤其是在膝关节平移方面，而髋关节和踝关节的屈伸角度也受到影响，这表明膝关节处的误差会传播到周围关节。髋关节、膝关节和踝关节运动学的这些变化导致髋关节和膝关节横向平面力矩以及膝关节额状平面力矩和力发生可测量的变化。由于可以使用皮肤表面标记物有效地表示膝关节屈曲角度，我们的工具利用这一可靠测量来指导膝关节的其他五个自由度，并为这些自由度提供更有效的运动学表示。
