Aurbach M, Špička J, Süß F, Vychytil J, Havelková L, Ryba T, Dendorfer S
Laboratory for Biomechanics, Ostbayerische Technische Hochschule (OTH) Regensburg, Regensburg, Germany.
Man-Machine Interaction Department, New Technologies - Research Center, University of West Bohemia in Pilsen, Univerzitní 8, 301 00 Pilsen, Czech Republic.
J Biomech. 2020 Aug 26;109:109864. doi: 10.1016/j.jbiomech.2020.109864. Epub 2020 Jun 1.
Musculoskeletal models of the shoulder complex are valuable research aids to investigate tears of the supraspinatus and the resulting mechanical impact during abduction of the humerus. One of the major contributors to this motion is the deltoid muscle group and for this, an accurate modeling of the lines of action is indispensable. The aim of this work was to utilize a torus obstacle wrapping approach for the deltoids of an existing shoulder model and assess the feasibility of the approach during humeral abduction. The shoulder model from the AnyBody™ modeling system was used as a platform. The size of the tori is based on a magnetic resonance imaging (MRI) approach and several kinematic couplings are implemented to determine the trajectories of the tori during abduction. To assess the model behavior, the moment arms of the virtual muscle elements and the resultant glenohumeral joint reaction force (GHJF) were compared with reference data from the literature during abduction of the humerus in the range 20°-120°. The root mean square error for the anterior, lateral and posterior part between the simulated muscle elements and reference data from the literature was 3.9, 1.7 and 5.8 mm, respectively. The largest deviation occurred on the outer elements of the muscle groups, with 12.6, 10.4 and 20.5 mm, respectively. During abduction, there is no overlapping of the muscle elements and these are in continuous contact with the torus obstacles, thus enabling a continuous force transmission. This results in a rising trend of the resultant GHJF. The torus obstacle approach as a wrapping method for the deltoid muscles provides a guided muscle pathing by simultaneously approximating the curvature of the deltoid muscle. The results from the comparison of the simulated moment arms and the resultant GHJF are in accordance with those in the literature in the range 20°-120° of abduction. Although this study shows the strength of the torus obstacle as a wrapping approach, the method of fitting the tori according to MRI data was not suitable. A cadaver study is recommended to better validate and mathematically describe the torus approach.
肩部复合体的肌肉骨骼模型是研究冈上肌撕裂及肱骨外展时所产生机械影响的重要研究辅助工具。此运动的主要贡献者之一是三角肌组，因此，准确模拟其作用线必不可少。本研究的目的是对现有肩部模型的三角肌采用环形障碍物包裹方法，并评估该方法在肱骨外展过程中的可行性。使用AnyBody™建模系统中的肩部模型作为平台。环形物的尺寸基于磁共振成像（MRI）方法确定，并且实施了几种运动学耦合来确定外展过程中环形物的轨迹。为了评估模型行为，在肱骨外展20°至120°范围内，将虚拟肌肉元件的力臂和合成的盂肱关节反作用力（GHJF）与文献中的参考数据进行了比较。模拟肌肉元件与文献参考数据之间，前部、外侧和后部的均方根误差分别为3.9、1.7和5.8毫米。最大偏差出现在肌肉组的外侧元件上，分别为12.6、10.4和20.5毫米。在外展过程中，肌肉元件没有重叠，并且它们与环形障碍物持续接触，从而实现连续的力传递。这导致合成GHJF呈上升趋势。环形障碍物方法作为三角肌的包裹方法，通过同时逼近三角肌的曲率提供了引导性的肌肉路径。在20°至120°外展范围内，模拟力臂和合成GHJF的比较结果与文献中的结果一致。尽管本研究显示了环形障碍物作为一种包裹方法的优势，但根据MRI数据拟合环形物的方法并不合适。建议进行尸体研究以更好地验证并从数学上描述环形物方法。
