Background:The glenoid track concept is used to determine preoperatively whether a Hill-Sachs defect is engaging or not. Currently, the glenoid track concept relies on measurements of bony structures as well as on the confines and elasticity of the rotator cuff as a reference point, which varies extensively among individuals and therefore limits the reliability and accuracy of this concept.Purpose:To evaluate the reliability of the global track concept, which determines the angular distance of the Hill-Sachs defect from the center of the articular surface of the humeral head as a new reference point with the help of an automated image analysis software and 3-dimensional analysis of the humeral head.Study Design:Controlled laboratory study.Methods:Computed tomography scans of 100 patients treated for anterior shoulder instability with different sizes of Hill-Sachs defects were evaluated manually by 2 orthopaedic surgeons independently using the software OsiriX as well as automatically by using a dedicated prototype software (ImFusion). Obtained manual and automated measurements included the Hill-Sachs length, Hill-Sachs width, and Hill-Sachs depth of the defect; the Hill-Sachs interval (HSI); and the glenoid width for the glenoid track concept, as well as the angular distance of the Hill-Sachs defect from the center of the articular surface of the humeral head (global track concept). The reliability of the different measurement techniques was compared by calculating intraclass correlation coefficients (ICCs).Results:There was a significant difference for all obtained parameters comparing manual and automatic measurements. For manually obtained parameters, measurements referring to bony boundaries (glenoid width, Hill-Sachs length, and Hill-Sachs width) showed good to excellent agreement (ICC, 0.86, 0.82, and 0.62, respectively), while measurements referring to soft tissue boundaries (HSI and glenoid track; ICC, 0.56 and 0.53, respectively) or not directly identifiable reference points (center of articular surface and global track) only showed fair reliability (ICC middle excursion, 0.42). When the same parameters were measured with the help of an automated software, good reliability for the glenoid track concept and excellent reliability for the global track concept in the middle excursion were achieved.Conclusion:The present study showed that the more complex global track measurements of humeral defects are more reliable than the current standard HSI and glenoid track measurements. However, this is only true when automated software is used to perform the measurements.Clinical Relevance:Future studies using the new proposed method in combination with an automated software need to be conducted to determine critical threshold values for defects prone to engagement.

中文翻译：

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用于评估肩部前不稳定的 Hill-Sachs 缺陷的全局轨迹概念

背景：关节盂轨道概念用于在术前确定 Hill-Sachs 缺损是否接合。目前，关节盂轨道概念依赖于骨结构的测量以及肩袖的限制和弹性作为参考点，这在个体之间差异很大，因此限制了该概念的可靠性和准确性。 目的：评估全局轨迹概念的可靠性，借助自动图像分析软件和 3 维分析，确定 Hill-Sachs 缺损距肱骨头关节面中心的角距离作为新的参考点研究设计：对照实验室研究。方法：2 名骨科医生使用 OsiriX 软件独立手动评估 100 名患有不同大小 Hill-Sachs 缺损的肩前不稳定患者的计算机断层扫描，并使用软件自动评估专用原型软件（ImFusion）。获得的手动和自动测量结果包括缺陷的 Hill-Sachs 长度、Hill-Sachs 宽度和 Hill-Sachs 深度；希尔-萨克斯区间 (HSI)；关节盂轨迹概念的关节盂宽度，以及 Hill-Sachs 缺损距肱骨头关节面中心的角距离（全局轨迹概念）。通过计算组内相关系数（ICC）来比较不同测量技术的可靠性。结果：与手动测量和自动测量相比，所有获得的参数均存在显着差异。对于手动获得的参数，参考骨边界（关节盂宽度、Hill-Sachs 长度和 Hill-Sachs 宽度）的测量显示出良好到极好的一致性（ICC 分别为 0.86、0.82 和 0.62），而参考软组织边界的测量（HSI 和关节盂轨迹；ICC，分别为 0.56 和 0.53）或不可直接识别的参考点（关节面中心和全局轨迹）仅显示出相当的可靠性（ICC 中间偏移，0.42）。当借助自动化软件测量相同的参数时，关节盂轨迹概念具有良好的可靠性，而中间行程的全局轨迹概念具有出色的可靠性。结论：本研究表明，更复杂的全局轨迹测量肱骨缺损比当前标准 HSI 和关节盂轨迹测量更可靠。然而，只有当使用自动化软件执行测量时，这才是正确的。 临床相关性：未来的研究需要结合使用新提出的方法和自动化软件来进行，以确定容易发生接合的缺陷的临界阈值。