Background: 

It is accepted by the orthopaedic community that the rotator cable (RCa) acts as a suspension bridge that stress shields the crescent area (CA). The goal of this study was to determine if the RCa does stress shield the CA during shoulder abduction.

Methods: 

The principal strain magnitude and direction in the RCa and CA and shoulder abduction force were measured in 20 cadaveric specimens. Ten specimens underwent a release of the anterior cable insertion followed by a posterior release. In the other 10, a release of the posterior cable insertion was followed by an anterior release. Testing was performed for the native, single-release, and full-release conditions. The thicknesses of the RCa and CA were measured.

Results: 

Neither the principal strain magnitude nor the strain direction in either the RCa or the CA changed with single or full RCa release (p ≥ 0.493). There were no changes in abduction force after single or full RCa release (p ≥ 0.180). The RCa and CA thicknesses did not differ from one another at any location (p ≥ 0.195).

Conclusions: 

The RCa does not act as a suspension bridge and does not stress shield the CA. The CA primarily transfers shoulder abduction force to the greater tuberosity.

Clinical Relevance: 

The CA is important in force transmission during shoulder abduction, and efforts should be made to restore its continuity with a repair or reconstruction.

中文翻译：

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在肩外展期间，旋转器电缆不会对新月区域进行应力屏蔽

背景： 

骨科界普遍认为，旋转电缆 (RCa) 充当悬索桥，可对新月形区域 (CA) 进行应力屏蔽。本研究的目的是确定 RCA 在肩外展期间是否确实对 CA 进行了应力保护。

方法： 

在 20 个尸体标本中测量了 RCa 和 CA 的主应变大小和方向以及肩部外展力。十个样本经历了前电缆插入的释放，然后是后释放。在另外 10 例中，释放后部电缆插入后进行前部释放。针对本机、单次发布和完全发布条件进行了测试。测量了 RCa 和 CA 的厚度。

结果： 

RCa 或 CA 中的主应变大小和应变方向都不会随着单次或完全 RCa 释放而改变 (p ≥ 0.493)。单次或完全 RCa 释放后外展力没有变化 (p ≥ 0.180)。RCa 和 CA 厚度在任何位置都没有差异 (p ≥ 0.195)。

结论： 

RCa 不充当悬索桥，也不对 CA 进行应力屏蔽。CA 主要将肩外展力传递到大结节。

临床相关性： 

CA 在肩外展过程中对力量传递很重要，应努力通过修复或重建来恢复其连续性。