Mura Nariyuki, O'Driscoll Shawn W, Zobitz Mark E, Heers Guido, Jenkyn Thomas R, Chou Siaw-Meng, Halder Andreas M, An Kai-Nan
Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN 55905, USA.
J Shoulder Elbow Surg. 2003 Mar-Apr;12(2):179-84. doi: 10.1067/mse.2003.9.
Rotator cuff ruptures that extend into the infraspinatus tendon may cause dysfunction and superior migration of the humerus. The purpose of this study was to determine whether a threshold size of infraspinatus defect exists beyond which abduction torque generation decreases and superior migration of the humeral head increases. Glenohumeral abduction torque and superior humeral head translations were measured in hanging arms in neutral rotation in cadaver shoulders (n = 10). Loads were applied to the rotator cuff tendons and the middle deltoid. After sequential detachment of the infraspinatus, abduction torque progressively decreased. At three-fifths detachment, abduction torque was significantly lower than after supraspinatus release alone (52% vs 61%, P <.05). Superior translation after complete supraspinatus and infraspinatus detachment increased significantly (P <.05), but no intermediate threshold was detected. Therefore, the entire infraspinatus contributes to abduction torque generation and stabilizes the humeral head against superior subluxation. Even with a tear extending into the superior infraspinatus, the infraspinatus contributes abduction force generation across the glenohumeral joint.
延伸至冈下肌腱的肩袖破裂可能导致功能障碍和肱骨向上移位。本研究的目的是确定是否存在一个冈下肌缺损的临界大小，超过该大小外展扭矩产生减少且肱骨头向上移位增加。在尸体肩部（n = 10）中立旋转的悬垂臂中测量盂肱外展扭矩和肱骨头向上移位。将负荷施加于肩袖肌腱和三角肌中部。在依次切断冈下肌后，外展扭矩逐渐降低。在五分之三切断时，外展扭矩显著低于仅松解冈上肌后（52%对61%，P <.05）。冈上肌和冈下肌完全切断后的向上移位显著增加（P <.05），但未检测到中间临界值。因此，整个冈下肌有助于外展扭矩的产生，并稳定肱骨头防止其向上半脱位。即使撕裂延伸至冈下肌上部，冈下肌仍有助于在盂肱关节产生外展力。
