Orthopaedic Department, Balgrist University Hospital, University of Zurich, Rämistrasse 71, 8006, Zurich, Switzerland.
BMC Musculoskelet Disord. 2013 Aug 19;14:247. doi: 10.1186/1471-2474-14-247.
It seems appropriate to assume, that for a full and strong global shoulder function a normally innervated and active deltoid muscle is indispensable. We set out to analyse the size and shape of the deltoid muscle on MR-arthrographies, and analyse its influence on shoulder function and its adaption (i.e. atrophy) for reduced shoulder function.
The fatty infiltration (Goutallier stages), atrophy (tangent sign) and selective myotendinous retraction of the rotator cuff, as well as the thickness and the area of seven anatomically defined segments of the deltoid muscle were measured on MR-arthrographies and correlated with shoulder function (i.e. active abduction). Included were 116 patients, suffering of a rotator cuff tear with shoulder mobility ranging from pseudoparalysis to free mobility. Kolmogorov-Smirnov test was used to determine the distribution of the data before either Spearman or Pearson correlation and a multiple regression was applied to reveal the correlations.
Our developed method for measuring deltoid area and thickness showed to be reproducible with excellent interobserver correlations (r = 0.814-0.982).The analysis of influencing factors on active abduction revealed a weak influence of the amount of SSP tendon (r = -0.25; p < 0.01) and muscle retraction (r = -0.27; p < 0.01) as well as the stage of fatty muscle infiltration (GFDI: r = -0.36; p < 0.01). Unexpectedly however, we were unable to detect a relation of the deltoid muscle shape with the degree of active glenohumeral abduction. Furthermore, long-standing rotator cuff tears did not appear to influence the deltoid shape, i.e. did not lead to muscle atrophy.
Our data support that in chronic rotator cuff tears, there seems to be no disadvantage to exhausting conservative treatment and to delay implantation of reverse total shoulder arthroplasty, as the shape of deltoid muscle seems only to be influenced by natural aging, but to be independent of reduced shoulder motion.
似乎可以假定，对于一个完整和强壮的全球肩部功能，正常神经支配和活跃的三角肌是不可或缺的。我们着手分析磁共振关节造影中三角肌的大小和形状，并分析其对肩部功能的影响及其适应（即萎缩）减少肩部功能。
在磁共振关节造影中测量肩袖的脂肪浸润（Goutallier 分期）、萎缩（切线征）和选择性肩袖肌肌腱回缩，以及七个解剖定义的三角肌段的厚度和面积，并与肩部功能（即主动外展）相关联。包括 116 名患者，患有肩袖撕裂，肩部活动范围从假性瘫痪到自由活动。使用 Kolmogorov-Smirnov 检验来确定数据的分布，然后进行 Spearman 或 Pearson 相关分析，以及应用多元回归来揭示相关性。
我们开发的三角肌面积和厚度测量方法具有良好的观察者间相关性（r = 0.814-0.982），具有很好的可重复性。对主动外展影响因素的分析表明，肩袖上旋肌腱（SSP）的数量（r = -0.25；p < 0.01）和肌肉回缩（r = -0.27；p < 0.01）以及肌肉脂肪浸润程度（GFDI：r = -0.36；p < 0.01）的影响较弱。然而，出乎意料的是，我们无法检测到三角肌形状与主动盂肱关节外展程度之间的关系。此外，长期肩袖撕裂似乎不会影响三角肌形状，即不会导致肌肉萎缩。
我们的数据支持在慢性肩袖撕裂中，似乎没有理由耗尽保守治疗并延迟反向全肩关节置换的植入，因为三角肌的形状似乎仅受自然衰老的影响，而与减少的肩部运动无关。
