McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, 424 Stemmler Hall, 36th and Hamilton Walk, Philadelphia, PA 19104, USA.
J Orthop Res. 2012 Sep;30(9):1435-9. doi: 10.1002/jor.22100. Epub 2012 Mar 9.
Rotator cuff repairs are commonly performed to reduce pain and restore function. Tears are also treated successfully without surgical intervention; however, the effect that a torn tendon has on the glenohumeral cartilage remains unknown. Clinically, a correlation between massive rotator cuff tears and glenohumeral arthritis has often been observed. This may be due to a disruption in the balance of forces at the shoulder, resulting in migration of the humeral head and subsequently, abnormal loading of the glenoid. Our lab previously demonstrated changes in ambulation and intact tendon mechanical properties following supraspinatus and infraspinatus rotator cuff tendon tears in a rat model. Therefore, the purpose of this study was to investigate the effects of supraspinatus and infraspinatus rotator cuff tears on the glenoid cartilage. Nine rats underwent unilateral detachment of the supraspinatus and infraspinatus tendons and were sacrificed after 4 weeks. Cartilage thickness significantly decreased in the antero-inferior region of injured shoulders. In addition, equilibrium elastic modulus significantly decreased in the center, antero-superior, antero-inferior, and superior regions. These results suggest that altered loading after rotator cuff injury may lead to damage to the joint with significant pain and dysfunction. Clinically, understanding the mechanical processes involved with joint damage will allow physicians to better advise patients.
肩袖修复通常用于减轻疼痛和恢复功能。撕裂也可以通过非手术干预成功治疗；然而，撕裂的肌腱对肩盂软骨的影响尚不清楚。临床上，常观察到巨大肩袖撕裂与肩关节炎之间存在相关性。这可能是由于肩部力量平衡的破坏，导致肱骨头的迁移，进而导致肩盂的异常负荷。我们实验室之前在大鼠模型中证明了肩袖冈上肌和冈下肌肌腱撕裂后步行和完整肌腱力学性能的变化。因此，本研究旨在探讨冈上肌和冈下肌肩袖撕裂对肩胛盂软骨的影响。9 只大鼠行单侧冈上肌和冈下肌肌腱分离，4 周后处死。损伤侧肩盂前下区软骨厚度明显变薄。此外，中心、前上、前下和上区的平衡弹性模量明显降低。这些结果表明，肩袖损伤后负荷的改变可能导致关节损伤，引起明显的疼痛和功能障碍。临床上，了解与关节损伤相关的力学过程将使医生能够更好地为患者提供建议。
