Department of Physical Therapy, University of Florida, Gainesville, FL, USA.
Departemento de Fisioterapia, Universidade Federal do Rio Grande do Norte, Natal, Brazil.
J Shoulder Elbow Surg. 2022 Feb;31(2):225-234. doi: 10.1016/j.jse.2021.09.007. Epub 2021 Oct 14.
The paucity of longitudinal clinical studies limits our understanding of the development of shoulder pain with repetitive shoulder tasks, and its association with underlying mind and body mechanisms. Tendon thickening characterizes painful shoulder supraspinatus tendinopathy, and the perception of pain can be affected by the presence of psychological factors such as anxiety and depression. This study determined the incidence of shoulder pain in novice individuals exposed to repetitive shoulder tasks, and the associated change in outcomes of supraspinatus tendon morphology and measures of anxiety and depression.
We recruited dental hygiene (DH) students (n = 45, novice and exposed to shoulder repetitive tasks) and occupational therapy (OT) students (n = 52, novice, but not exposed to shoulder repetitive tasks), following them over their first year of training. We measured shoulder pain, supraspinatus morphology via ultrasonography, and psychosocial distress via the Hospital Anxiety and Depression Scale. We compared the incidence of shoulder pain (defined as a change of visual analog scale for pain score greater than the minimal clinically important difference) between DH and OT students using Fisher exact test. We used mixed effects models to longitudinally compare the change in outcomes between 3 groups: DH students who develop and did not develop shoulder pain, and OT students.
The incidence of shoulder pain is higher in DH students (relative risk = 4.0, 95% confidence interval [CI] 1.4, 11.4). After 1 year, DH students with pain had the greatest thickening of the supraspinatus (0.7 mm, 95% CI 0.4, 0.9). The change in supraspinatus thickness of DH students with pain was greater than both DH students with no pain (0.4 mm, 95% CI 0.1, 0.8) and OT students (0.9 mm, 95% CI 0.5, 1.2). Anxiety score increased 3.8 points (95% CI 1.6, 5.1) in DH students with pain, and 43% of DH students with pain had abnormal anxiety score at 1 year (relative risk = 2.9, 95% CI 1.0, 8.6).
Our results provide support for the theoretical model of repetitive load as a mechanism of tendinopathy. The supraspinatus tendon thickens in the presence of repetitive tasks, and it thickens the most in those who develop shoulder pain. Concurrently, anxiety develops with shoulder pain, indicating a potential maladaptive central mechanism that may impact the perception of pain.
重复性肩部任务导致肩痛的发展及其与潜在身心机制的关系，我们对此知之甚少，这限制了我们的理解。肩袖上肌腱增厚是肩部疼痛的特征，疼痛的感知会受到焦虑和抑郁等心理因素的影响。本研究旨在确定暴露于重复性肩部任务的新手个体出现肩部疼痛的发生率，以及肩袖上肌腱形态和焦虑、抑郁测量结果的变化。
我们招募了牙科保健（DH）学生（45 名，新手，且暴露于肩部重复性任务）和职业治疗（OT）学生（52 名，新手，但未暴露于肩部重复性任务），并在他们培训的第一年对他们进行随访。我们通过超声检查测量肩部疼痛、肩袖形态，通过医院焦虑和抑郁量表测量心理社会困扰。我们使用 Fisher 精确检验比较 DH 和 OT 学生之间肩部疼痛（定义为疼痛评分的视觉模拟量表变化大于最小临床重要差异）的发生率。我们使用混合效应模型对 3 组（发展和未发展肩部疼痛的 DH 学生和 OT 学生）的结果进行纵向比较。
DH 学生的肩部疼痛发生率更高（相对风险=4.0，95%置信区间[CI]1.4，11.4）。1 年后，有疼痛的 DH 学生的肩袖上最厚（0.7mm，95%CI0.4，0.9）。有疼痛的 DH 学生的肩袖上厚度变化大于无疼痛的 DH 学生（0.4mm，95%CI0.1，0.8）和 OT 学生（0.9mm，95%CI0.5，1.2）。有疼痛的 DH 学生的焦虑评分增加了 3.8 分（95%CI1.6，5.1），并且 43%的有疼痛的 DH 学生在 1 年内出现异常焦虑评分（相对风险=2.9，95%CI1.0，8.6）。
我们的研究结果为重复性负荷作为一种肌腱病发病机制的理论模型提供了支持。在重复性任务的存在下，肩袖上肌腱会增厚，在出现肩部疼痛的患者中，肩袖上肌腱增厚最为明显。同时，焦虑与肩部疼痛一起发展，这表明潜在的适应性中枢机制可能会影响疼痛的感知。
