Orthopedic Robotics Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
J Orthop Res. 2021 Mar;39(3):648-656. doi: 10.1002/jor.24860. Epub 2020 Sep 28.
Capsular injuries can occur during multiple shoulder dislocations. The purpose of this study is to evaluate the location and magnitude of glenohumeral capsular injury following multiple dislocations. We hypothesized that the magnitude of capsular injury would increase and the location of peak injury would vary depending on the number of dislocations. Seven fresh-frozen cadaveric shoulders were used. A 7 × 11 grid of strain markers was affixed to the anteroinferior capsule. Each joint was then mounted to a six degree-freedom robotic testing system. Marker tracking was performed following 1, 2, 3, 4, 5, and 10 dislocations to determine the nonrecoverable strain as capsular injury. Following each dislocation, the magnitude of the maximum principal strain representing the nonrecoverable strain in the inferior glenohumeral capsule was quantified by comparing the strain marker positions following each dislocation. The peak value of nonrecoverable strain statistically increased with the number of dislocations in five of seven specimens (p = .0007). The capsular location that had the peak value of nonrecoverable strain varied according to the number of dislocations, and from specimen to specimen. The nonrecoverable strain was identified in the posterior capsule and anterior axillary pouch, which increased with the number of dislocations compared to the other regions of the capsule (p = .001-.012) by up to 16%. Clinical significance: While plication of the anterior axillary pouch is important following multiple dislocations, a more extensive anterior capsular shift may be necessary with an increased number of dislocations in addition to a posterior capsular shift when appropriate.
在多次肩关节脱位过程中可能会发生关节囊损伤。本研究旨在评估多次脱位后盂肱关节囊损伤的位置和程度。我们假设关节囊损伤的程度会增加，且损伤的峰值位置会因脱位次数的不同而变化。本研究使用了 7 个新鲜冷冻的尸体肩关节。在关节囊前下区域附着了一个 7×11 的应变标记网格。然后，将每个关节安装到一个六自由度机器人测试系统。在进行 1、2、3、4、5 和 10 次脱位后，通过跟踪标记点来确定不可恢复的应变，即关节囊损伤。在每次脱位后，通过比较每次脱位后的应变标记点位置，定量评估下盂肱关节囊不可恢复应变的最大主应变。在五个标本中的七个中，不可恢复应变的峰值随脱位次数的增加而增加（p=0.0007）。不可恢复应变的峰值位置随脱位次数的不同而变化，并且在不同标本之间也有所不同。与关节囊的其他区域相比，后关节囊和前腋窝区域的不可恢复应变（p=0.001-0.012）增加了 16%。不可恢复应变在后关节囊和前腋窝区域被识别出来，与其他区域相比，后关节囊和前腋窝区域的不可恢复应变随着脱位次数的增加而增加，最多可达 16%。临床意义：尽管在前腋窝区域进行折叠术对于多次脱位很重要，但随着脱位次数的增加，可能需要进行更广泛的前关节囊移位，并且在适当情况下还需要进行后关节囊移位。
