McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA, USA.
J Biomech. 2013 Jul 26;46(11):1818-24. doi: 10.1016/j.jbiomech.2013.05.007. Epub 2013 Jun 12.
Large rotator cuff tears (supraspinatus and infraspinatus) are common in patients who perform overhead activities (laborers, athletes). In addition, following large cuff tears, these patients commonly attempt to return to pre-injury activity levels. However, there is a limited understanding of the damaging effects on the uninjured joint tissues when doing so. Therefore, the objective of this study was to investigate the effect of returning to overuse activity following a supraspinatus and infraspinatus tear on shoulder function and the structural and biological properties of the intact tendons and glenoid cartilage. Forty rats underwent 4 weeks of overuse followed by detachment of the supraspinatus and infraspinatus tendons and were then randomized into two groups: return to overuse or cage activity. Ambulatory measurements were performed over time and structural and biological properties of the adjacent tendons and cartilage were evaluated. Results demonstrated that animals returning to overuse activity did not have altered shoulder function but despite this, did have altered cartilage and tendon properties. These mechanical changes corresponded to altered transcriptional regulation of chondrogenic genes within cartilage and tendon. This study helps define the mechanical and biological mechanisms leading to joint damage and provides a framework for treating active cuff tear patients.
巨大的肩袖撕裂（冈上肌和冈下肌）在从事过顶活动的患者中很常见（劳动者、运动员）。此外，在巨大的肩袖撕裂后，这些患者通常试图恢复到受伤前的活动水平。然而，对于在这样做时对未受伤的关节组织的破坏性影响，我们的理解有限。因此，本研究的目的是调查在冈上肌和冈下肌撕裂后恢复过度活动对肩部功能以及完整肌腱和肩胛盂软骨的结构和生物学特性的影响。40 只大鼠进行了 4 周的过度使用，然后冈上肌和冈下肌肌腱分离，然后随机分为两组：恢复过度使用或笼式活动。随着时间的推移进行了步行测量，并评估了相邻肌腱和软骨的结构和生物学特性。结果表明，恢复过度活动的动物的肩部功能没有改变，但尽管如此，它们的软骨和肌腱特性还是发生了改变。这些力学变化与软骨和肌腱内软骨生成基因的转录调控改变相对应。这项研究有助于确定导致关节损伤的机械和生物学机制，并为治疗活跃的肩袖撕裂患者提供了框架。
