Department of Biomedical Engineering, University of Basel, Basel, Switzerland.
Department of Orthopaedics and Traumatology, University Hospital Basel, Basel, Switzerland.
J Orthop Traumatol. 2023 Aug 4;24(1):41. doi: 10.1186/s10195-023-00720-8.
Rotator cuff muscles stabilise the glenohumeral joint and contribute to the initial abduction phase with other shoulder muscles. This study aimed to determine if the load-induced increase in shoulder muscle activity during a 30° abduction test is influenced by asymptomatic or symptomatic rotator cuff pathologies.
Twenty-five patients with unilateral rotator cuff tears (age, 64.3 ± 10.2 years), 25 older control subjects (55.4 ± 8.2 years) and 25 younger control subjects (26.1 ± 2.3 years) participated in this study. Participants performed a bilateral 30° arm abduction and adduction movement in the scapular plane with handheld weights (0-4 kg). Activity of the deltoid, infraspinatus, biceps brachii, pectoralis major, latissimus dorsi and upper trapezius muscles was analysed at maximum abduction angle after normalisation to maximum voluntary contraction. Shoulders were classified into rotator cuff tendinopathy, asymptomatic and symptomatic rotator cuff tears, and healthy based on magnetic resonance images. A linear mixed model (loads, shoulder types) with random effects (shoulder identification) was applied to the log-transformed muscle activities.
Muscle activity increased with increasing load in all muscles and shoulder types (P < 0.001), and 1-kg increments in additional weights were significant (P < 0.001). Significant effects of rotator cuff pathologies were found for all muscles analysed (P < 0.05). In all muscles, activity was at least 20% higher in symptomatic rotator cuff tears than in healthy shoulders (P < 0.001). Symptomatic rotator cuff tears showed 20-32% higher posterior deltoid (P < 0.05) and 19-25% higher pectoralis major (P < 0.01) activity when compared with asymptomatic tears.
Rotator cuff pathologies are associated with greater relative activity of shoulder muscles, even with low levels of additional load. Therefore, the inclusion of loaded shoulder tests in the diagnosis and rehabilitation of rotator cuff pathologies can provide important insight into the functional status of shoulders and can be used to guide treatment decisions.
Level 2.
Ethical approval was obtained from the regional ethics committee (Ethics Committee Northwest Switzerland EKNZ 2021-00182), and the study was registered at clinicaltrials.gov on 29 March 2021 (trial registration number NCT04819724, https://clinicaltrials.gov/ct2/show/NCT04819724 ).
肩袖肌肉稳定盂肱关节，并与其他肩部肌肉一起参与初始外展阶段。本研究旨在确定在 30°外展测试中，由负荷引起的肩部肌肉活动增加是否受无症状或有症状的肩袖病变影响。
25 名单侧肩袖撕裂患者（年龄 64.3±10.2 岁）、25 名年龄较大的对照组（55.4±8.2 岁）和 25 名年龄较小的对照组（26.1±2.3 岁）参加了这项研究。参与者在肩胛平面上用手持重物（0-4kg）进行双侧 30°手臂外展和内收运动。在正常化至最大自主收缩后，分析最大外展角度时三角肌、冈下肌、肱二头肌、胸大肌、背阔肌和上斜方肌的活动。根据磁共振成像，将肩分为肩袖肌腱病、无症状和有症状的肩袖撕裂以及健康。对数转换后的肌肉活动采用带有随机效应（肩部识别）的线性混合模型（负荷、肩部类型）进行分析。
所有肌肉和肩部类型的肌肉活动均随负荷的增加而增加（P<0.001），并且增加 1kg 的额外重量具有显著意义（P<0.001）。在所有分析的肌肉中，肩袖病变都有显著影响（P<0.05）。在所有肌肉中，与健康肩部相比，有症状的肩袖撕裂的活动至少高出 20%（P<0.001）。与无症状的肩袖撕裂相比，有症状的肩袖撕裂的后三角肌（P<0.05）和胸大肌（P<0.01）活动分别高出 20-32%和 19-25%。
即使在低水平的附加负荷下，肩袖病变也与肩部肌肉的相对活动度增加有关。因此，在肩袖病变的诊断和康复中纳入负重肩部测试，可以提供对肩部功能状态的重要了解，并可用于指导治疗决策。
2 级。
本研究已获得区域伦理委员会（西北瑞士伦理委员会 EKNZ 2021-00182）的伦理批准，并于 2021 年 3 月 29 日在 clinicaltrials.gov 上注册（试验注册号：NCT04819724，https://clinicaltrials.gov/ct2/show/NCT04819724）。
