Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
Shoulder and Elbow Mechanical Research Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
J Bone Joint Surg Am. 2022 Jul 20;104(14):1292-1300. doi: 10.2106/JBJS.21.01142. Epub 2022 Apr 27.
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.
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.
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).
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.
The CA is important in force transmission during shoulder abduction, and efforts should be made to restore its continuity with a repair or reconstruction.
矫形医学界普遍认为，旋转带缆线（RCa）起到悬索桥的作用，为月牙区（CA）提供应力屏蔽。本研究旨在确定在肩部外展过程中 RCa 是否对 CA 产生应力屏蔽作用。
在 20 个尸体标本中测量了 RCa 和 CA 的主应变幅度和方向，以及肩部外展力。10 个标本先进行前缆线插入松解，然后进行后缆线插入松解。在另外 10 个标本中，先进行后缆线插入松解，然后进行前缆线插入松解。对原始、单释放和全释放条件进行了测试。测量了 RCa 和 CA 的厚度。
RCa 和 CA 中的主应变幅度或应变方向在单释放或全释放 RCa 后均未发生变化（p≥0.493）。RCa 单释放或全释放后，外展力无变化（p≥0.180）。RCa 和 CA 的厚度在任何位置均无差异（p≥0.195）。
RCa 不作为悬索桥，不会对 CA 产生应力屏蔽作用。CA 主要将肩部外展力传递至大结节。
CA 在肩部外展过程中的力传递中很重要，应努力通过修复或重建来恢复其连续性。
