Sensory-Motor Systems (SMS) Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, Switzerland.
Department of Clinical Science, Intervention and Technology (Clintec), Karolinska Institute, Stockholm, Sweden.
Sci Rep. 2022 Aug 16;12(1):13856. doi: 10.1038/s41598-022-17984-5.
Knowledge about the orientation of a representative ankle joint axis is limited to studies of tarsal morphology and of quasistatic movements. The aim of our study was therefore to determine the development of the axis orientation during walking. Intracortical bone pins were used to monitor the kinematics of the talus and tibia of five healthy volunteers. The finite helical axis was determined for moving windows of 10% stance phase and its orientation reported if the rotation about the axis was more than 2°. A representative axis for ankle dorsi- and plantarflexion was also estimated based on tarsal morphology. As reported by literature, the morphology-based axis was inclined more medially upwards for dorsiflexion than for plantarflexion. However, when a mean of the finite helical axis orientations was calculated for each walking trial for dorsiflexion (stance phase 15-25%) and for plantarflexion (stance phase 85-95%), the inclination was less medially upwards in dorsiflexion than in plantarflexion in four out of five participants. Thus, it appears that the inclination of a representative ankle joint axis for dynamic loading situations cannot be estimated from either morphology or quasi-static experiments. Future studies assessing muscle activity, ligament behaviour and articulating surfaces may help to identify the determining factors for the orientation of a representative ankle joint axis.
关于代表性踝关节轴的方向的知识仅限于跗骨形态学和准静态运动的研究。因此，我们的研究目的是确定在行走过程中轴方向的发展。我们使用皮质内骨钉来监测五个健康志愿者的距骨和胫骨的运动学。对于 10%的支撑相移动窗口，确定有限螺旋轴的方向，如果围绕该轴的旋转超过 2°，则报告其方向。还根据跗骨形态学估计了用于踝关节背屈和跖屈的代表性轴。如文献所述，基于形态的轴在背屈时比在跖屈时更向内侧向上倾斜。然而，当为每个行走试验计算背屈（支撑相 15-25%）和跖屈（支撑相 85-95%）的有限螺旋轴方向的平均值时，在四个参与者中的五个参与者中，背屈时的倾斜度小于跖屈时的倾斜度。因此，似乎不能根据形态或准静态实验来估计用于动态加载情况的代表性踝关节轴的倾斜度。未来评估肌肉活动、韧带行为和关节表面的研究可能有助于确定代表性踝关节轴的方向的决定因素。
