Department of Rehabilitation, Hitsujigaoka Hospital, Sapporo, Japan.
Second Division of Physical Therapy, School of Health Sciences, Sapporo Medical University, Sapporo, Japan.
Clin Anat. 2022 Jan;35(1):94-102. doi: 10.1002/ca.23800. Epub 2021 Oct 26.
This study aimed to compare the effect of the load of the upper limb on the stiffness of supraspinatus muscle regions during isometric shoulder abduction in the scapular plane in healthy individuals and patients with a rotator cuff tear. Thirteen male patients were scheduled for arthroscopic rotator cuff repair, and 13 healthy male individuals were recruited. The movement task involved 30° isometric shoulder abduction in the scapular plane. The tasks included passive abduction, abduction with half-weight of the upper limb (1/2-weight), and full weight of the upper limb (full-weight). The stiffness of the supraspinatus muscle (anterior superficial, anterior deep, posterior superficial, and posterior deep regions) was recorded using ultrasound shear-wave elastography. The stiffness of the anterior superficial region on the affected side was significantly lower than that on the control side for the 1/2-weight and full-weight tasks. The stiffness of the anterior deep, posterior superficial, and posterior deep regions was not affected. This is the first study that investigated the mechanical effects of different loads on different supraspinatus muscle regions in rotator cuff tear patients. Our results indicate that the anterior superficial region in rotator cuff tear patients was mainly responsible for reduced active stiffness. This might be because this region contributes to force exertion and exhibits atrophy in rotator cuff tears. Hence, the anterior superficial region could be a focal point of quantitative dysfunction evaluation of the supraspinatus muscle in the case of a rotator cuff tear.
本研究旨在比较健康个体和肩袖撕裂患者在肩胛平面内等长肩外展时，上肢负荷对上肩袖肌区刚度的影响。13 名男性肩袖撕裂患者拟行关节镜肩袖修复术，同时招募 13 名健康男性作为对照。运动任务包括 30°肩胛平面内等长肩外展。任务包括被动外展、上肢半重（1/2 重）外展和全重（全重）外展。使用超声剪切波弹性成像记录冈上肌（前浅层、前深层、后浅层和后深层）的刚度。患侧前浅层区在 1/2 重和全重任务时的刚度明显低于对侧。前深层、后浅层和后深层的刚度不受影响。这是第一项研究不同负荷对肩袖撕裂患者不同冈上肌区力学影响的研究。我们的结果表明，肩袖撕裂患者的前浅层区主要负责主动刚度降低。这可能是因为该区域参与力量的产生，在肩袖撕裂中会发生萎缩。因此，在前肩袖撕裂的情况下，前浅层区可能是冈上肌定量功能障碍评估的一个焦点。
