Navacchia Alessandro, Kefala Vasiliki, Shelburne Kevin B
Center for Orthopaedic Biomechanics, The University of Denver, Denver, CO, USA.
Department of Mechanical and Materials Engineering, The University of Denver, 2390 S. York St., Denver, CO, 80208, USA.
Ann Biomed Eng. 2017 Mar;45(3):789-798. doi: 10.1007/s10439-016-1728-x. Epub 2016 Sep 12.
Quantification of muscle moment arms is important for clinical evaluation of muscle pathology and treatment, and for estimating muscle and joint forces in musculoskeletal models. Moment arms estimated with musculoskeletal models often assume a default motion of the knee derived from measurements of passive cadaveric flexion. However, knee kinematics are unique to each person and activity. The objective of this study was to estimate moment arms of the knee muscles with in vivo subject- and activity-specific kinematics from seven healthy subjects performing seated knee extension and single-leg lunge to show changes between subjects and activities. 3D knee motion was measured with a high-speed stereo-radiography system. Moment arms of ten muscles were estimated in OpenSim by replacing the default knee motion with in vivo measurements. Estimated inter-subject moment arm variability was similar to previously reported in vitro measurements. RMS deviations up to 9.0 mm (35.2% of peak value) were observed between moment arms estimated with subject-specific knee extension and passive cadaveric motion. The degrees of freedom that most impacted inter-activity differences were superior/inferior and anterior/posterior translations. Musculoskeletal simulations used to estimate in vivo muscle forces and joint loads may provide significantly different results when subject- and activity-specific kinematics are implemented.
肌肉力臂的量化对于肌肉病理学的临床评估和治疗以及在肌肉骨骼模型中估计肌肉和关节力而言至关重要。利用肌肉骨骼模型估计的力臂通常假定膝关节的默认运动源自被动尸体屈曲测量。然而，膝关节运动学因个体和活动而异。本研究的目的是根据7名健康受试者进行坐姿膝关节伸展和单腿弓步动作时体内特定个体和活动的运动学来估计膝关节肌肉的力臂，以显示个体和活动之间的差异。使用高速立体放射成像系统测量三维膝关节运动。通过在OpenSim中用体内测量值取代默认膝关节运动来估计10块肌肉的力臂。估计的个体间力臂变异性与先前报道的体外测量结果相似。在用特定个体的膝关节伸展和被动尸体运动估计的力臂之间观察到高达9.0毫米（峰值的35.2%）的均方根偏差。对活动间差异影响最大的自由度是上下平移和前后平移。当采用特定个体和活动的运动学时，用于估计体内肌肉力和关节负荷的肌肉骨骼模拟可能会提供显著不同的结果。
