Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo, Japan.
Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo, Japan.
Arthroscopy. 2018 Jun;34(6):1776-1784. doi: 10.1016/j.arthro.2018.01.011. Epub 2018 Feb 9.
To evaluate the distance and position of humeral head translation during glenohumeral motion and to investigate the function of the rotator cuff in glenohumeral translation.
Using 9 cadavers, glenohumeral translation during passive pendulum motion was tracked by an optical motion capture system. Tension was applied to 5 compartments of the rotator cuff muscles, and 7 different conditions of rotator cuff dysfunction were sequentially simulated. Three-dimensional glenohumeral structure was reconstructed from the computed tomography images of the specimens, and the distance and position of glenohumeral translation were compared among the conditions.
The average radius of glenohumeral translation was 10.6 ± 4.3 mm when static loading was applied to all rotator cuff muscles. The radius increased significantly in the models without traction force on the supraspinatus and total subscapularis tendons (P = .030). The position of the translation center did not change in the mediolateral direction (P = .587) and in the anteroposterior direction (P = .138), but it moved significantly superiorly in the models without supraspinatus and infraspinatus loading (P = .011) and in those without supraspinatus, infraspinatus, and teres minor loading (P < .001).
The distance and position of humeral head translation during glenohumeral motion changed with rotator cuff deficiency. The present study indicated that the subscapularis plays an important role in maintaining the central position of the humeral head, and that the infraspinatus acts as a major depressor of the humeral head during shoulder motion.
The results of this study suggest that extension of a tear into the subscapularis should be avoided to maintain the centering function of the glenohumeral joint in cases with rotator cuff tear.
评估肩盂在肩肱运动过程中的平移距离和位置，并研究肩袖在肩盂平移中的作用。
使用 9 具尸体，通过光学运动捕捉系统跟踪被动摆动手臂运动时的肩盂平移。向肩袖肌肉的 5 个部位施加张力，并依次模拟 7 种不同的肩袖功能障碍情况。从标本的 CT 图像重建三维肩盂结构，并比较各条件下肩盂平移的距离和位置。
当所有肩袖肌肉均受到静态负荷时，肩盂平均平移半径为 10.6 ± 4.3 mm。当冈上肌和肩胛下肌全部肌腱无牵引力时，半径显著增大（P =.030）。平移中心的位置在中外向（P =.587）和前后向（P =.138）均无变化，但在冈上肌和冈下肌无负荷以及冈上肌、冈下肌和小圆肌无负荷模型中，显著向上移动（P =.011 和 P <.001）。
肩盂在肩肱运动中的平移距离和位置随肩袖缺损而改变。本研究表明，肩胛下肌在维持肱骨头中心位置方面起重要作用，冈下肌在肩部运动时是肱骨头的主要降压器。
本研究结果表明，在肩袖撕裂的情况下，为了维持盂肱关节的中心功能，应避免撕裂延伸至肩胛下肌。
