Vidt Meghan E, Santago Anthony C, Marsh Anthony P, Hegedus Eric J, Tuohy Christopher J, Poehling Gary G, Freehill Michael T, Miller Michael E, Saul Katherine R
Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, Wake Forest Baptist Health, Biomedical Engineering, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, Wake Forest Baptist Health, Biomedical Engineering, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
Clin Biomech (Bristol). 2018 Dec;60:20-29. doi: 10.1016/j.clinbiomech.2018.10.004. Epub 2018 Oct 4.
Rotator cuff tears in older individuals may result in decreased muscle forces and changes to force distribution across the glenohumeral joint. Reduced muscle forces may impact functional task performance, altering glenohumeral joint contact forces, potentially contributing to instability or joint damage risk. Our objective was to evaluate the influence of rotator cuff muscle force distribution on glenohumeral joint contact force during functional pull and axilla wash tasks using individualized computational models.
Fourteen older individuals (age 63.4 yrs. (SD 1.8)) were studied; 7 with rotator cuff tear, 7 matched controls. Muscle volume measurements were used to scale a nominal upper limb model's muscle forces to develop individualized models and perform dynamic simulations of movement tracking participant-derived kinematics. Peak resultant glenohumeral joint contact force, and direction and magnitude of force components were compared between groups using ANCOVA.
Results show individualized muscle force distributions for rotator cuff tear participants had reduced peak resultant joint contact force for pull and axilla wash (P ≤ 0.0456), with smaller compressive components of peak resultant force for pull (P = 0.0248). Peak forces for pull were within the glenoid. For axilla wash, peak joint contact was directed near/outside the glenoid rim for three participants; predictions required individualized muscle forces since nominal muscle forces did not affect joint force location.
Older adults with rotator cuff tear had smaller peak resultant and compressive forces, possibly indicating increased instability or secondary joint damage risk. Outcomes suggest predicted joint contact force following rotator cuff tear is sensitive to including individualized muscle forces.
老年个体的肩袖撕裂可能导致肌肉力量下降，并改变整个盂肱关节的力分布。肌肉力量的降低可能会影响功能任务的执行，改变盂肱关节的接触力，从而可能增加不稳定或关节损伤的风险。我们的目标是使用个性化计算模型，评估在功能性拉伸和腋下清洗任务中肩袖肌肉力分布对盂肱关节接触力的影响。
对14名老年人（年龄63.4岁（标准差1.8））进行了研究；7名患有肩袖撕裂，7名匹配的对照组。通过肌肉体积测量来缩放名义上肢模型的肌肉力量，以开发个性化模型，并进行运动跟踪参与者运动学的动态模拟。使用协方差分析比较两组之间盂肱关节接触力的峰值合力以及力分量的方向和大小。
结果显示，肩袖撕裂参与者的个性化肌肉力分布在拉伸和腋下清洗时的峰值合力接触力降低（P≤0.0456），拉伸时峰值合力中的压缩分量较小（P = 0.0248）。拉伸时的峰值力在关节盂内。对于腋下清洗，三名参与者的峰值关节接触指向关节盂边缘附近/外侧；由于名义肌肉力不影响关节力位置，因此预测需要个性化肌肉力。
患有肩袖撕裂的老年人的峰值合力和压缩力较小，这可能表明不稳定或继发性关节损伤风险增加。结果表明，肩袖撕裂后预测的关节接触力对纳入个性化肌肉力很敏感。
