Li Junyan
School of Science and Technology, Middlesex University, London, NW4 4BT, United Kingdom.
J Mech Behav Biomed Mater. 2021 Jan;113:104136. doi: 10.1016/j.jmbbm.2020.104136. Epub 2020 Oct 10.
Musculoskeletal models provide non-invasive and subject-specific biomechanical investigations of the musculoskeletal system. In a musculoskeletal model, muscle forces contribute to the deformation and kinematics of the joint which in turn would alter moment arms of muscles and ground reaction forces and thus affect the prediction of muscle forces and contact forces and contact mechanics of the joint. By far, deformable contact models of the hip have not been considered in musculoskeletal models, and the role of kinematics and deformation within the hip in muscle forces and hip contact mechanics is unknown. In this study, an FE musculoskeletal model including bones, joints and muscles of the lower extremity was developed. A deformable contact model of the hip joint was incorporated and coupled into the musculoskeletal model. Joint angles and ground reaction forces during gait were used as inputs. Optimization minimizing the sum of muscle stresses squared was performed directly to the FE musculoskeletal model in order to simultaneously solve muscle forces and contact forces and contact stresses of the hip joint within a single framework. The calculated hip contact forces corresponded well to the in vivo measurement data. The maximum hip contact stress was 6.5 MPa and occurred at weight-acceptance. The influence of kinematics and deformation in the hip on muscles forces and hip contact forces was minimal and not sensitive to variations in the thickness and properties of the joint cartilage during gait. This suggests that the uncoupled approach in which the hip contact forces and contact mechanics are simulated in separate frameworks would serve as an effective and efficient alternative for subject-specific modelling of the hip. This study provides guidance for the level of complexity needed for future hip models and can be used to evaluate biomechanical changes of the musculoskeletal system following interventions.
肌肉骨骼模型提供了对肌肉骨骼系统的非侵入性且针对个体的生物力学研究。在肌肉骨骼模型中，肌肉力有助于关节的变形和运动学，而这反过来又会改变肌肉的力臂和地面反作用力，从而影响肌肉力和接触力以及关节接触力学的预测。到目前为止，肌肉骨骼模型尚未考虑髋关节的可变形接触模型，并且髋关节内的运动学和变形在肌肉力和髋关节接触力学中的作用尚不清楚。在本研究中，开发了一个包括下肢骨骼、关节和肌肉的有限元肌肉骨骼模型。将髋关节的可变形接触模型纳入并耦合到肌肉骨骼模型中。步态期间的关节角度和地面反作用力用作输入。直接对有限元肌肉骨骼模型进行优化，以使肌肉应力平方和最小化，以便在单个框架内同时求解肌肉力、接触力以及髋关节的接触应力。计算得到的髋关节接触力与体内测量数据吻合良好。最大髋关节接触应力为6.5兆帕，出现在承重阶段。髋关节内的运动学和变形对肌肉力和髋关节接触力的影响极小，并且在步态期间对关节软骨厚度和特性的变化不敏感。这表明在单独框架中模拟髋关节接触力和接触力学的解耦方法将成为针对个体的髋关节建模的一种有效且高效的替代方法。本研究为未来髋关节模型所需的复杂程度提供了指导，并可用于评估干预后肌肉骨骼系统的生物力学变化。
