Institute of Biomedical Engineering, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei 100, Taiwan, ROC.
J Biomech. 2011 Apr 7;44(6):1182-8. doi: 10.1016/j.jbiomech.2011.01.009.
Biomechanics of the knee during stair-ascent has mostly been studied using skin-marker-based motion analysis techniques, but no study has reported a complete assessment of the soft tissue artifacts (STA) and their effects on the calculated joint center translation, angles and moments at the knee in normal subjects during this activity. This study aimed to bridge the gap. Twelve young adults walked up a three-step stair while data were acquired simultaneously from a three-dimensional motion capture system, a force plate and a dynamic fluoroscopy system. The "gold standards" of poses of the knee were obtained using a 3D fluoroscopy method. The STA of the markers on the thigh and shank were then calculated, together with their effects on the calculated joint center translations, angles and moments at the knee. The STA of the thigh markers were greater than those on the shank, leading to significantly underestimated flexion and extensor moments, but overestimated joint center translations during the first half of the stance phase. The results will be useful for a better understanding of the normal biomechanics of the knee during stair-ascent, as a baseline for future clinical applications and for developing a compensation method to correct for the effects of STA.
在楼梯上升过程中，膝关节的生物力学主要使用基于皮肤标记的运动分析技术进行研究，但没有研究报告全面评估正常受试者在该活动中软组织伪影（STA）及其对计算得到的关节中心平移、角度和膝关节力矩的影响。本研究旨在弥补这一空白。12 名年轻人在走上三级台阶的同时，从三维运动捕捉系统、力板和动态荧光透视系统同步采集数据。使用三维荧光透视方法获得膝关节的“黄金标准”姿势。然后计算大腿和小腿标记物的 STA 及其对膝关节计算得到的关节中心平移、角度和力矩的影响。大腿标记物的 STA 大于小腿标记物，导致在站立前期，伸肌和屈肌力矩明显低估，但关节中心平移被高估。研究结果有助于更好地理解楼梯上升过程中膝关节的正常生物力学，为未来的临床应用提供基线，并开发一种补偿方法来纠正 STA 的影响。
