Beeler Silvan, Leoty Laura, Hochreiter Bettina, Carrillo Fabio, Götschi Tobias, Fischer Tim, Fürnstahl Philipp, Gerber Christian
Department of Orthopaedic Surgery, University of Zürich, Balgrist University Hospital, Zürich, Switzerland.
Research in Orthopedic Computer Science (ROCS), University of Zürich, Balgrist University Hospital, Zürich, Switzerland.
JSES Int. 2021 Jan 15;5(2):181-189. doi: 10.1016/j.jseint.2020.11.003. eCollection 2021 Mar.
There is evidence that specific variants of scapular morphology are associated with dynamic and static posterior shoulder instability. To this date, observations regarding glenoid and/or acromial variants were analyzed independently, with two-dimensional imaging or without comparison with a healthy control group. Therefore, the purpose of this study was to analyze and describe the three-dimensional (3D) shape of the scapula in healthy and in shoulders with static or dynamic posterior instability using 3D surface models and 3D measurement methods.
In this study, 30 patients with unidirectional posterior instability and 20 patients with static posterior humeral head subluxation (static posterior instability, Walch B1) were analyzed. Both cohorts were compared with a control group of 40 patients with stable, centered shoulders and without any clinical symptoms. 3D surface models were obtained through segmentation of computed tomography images and 3D measurements were performed for glenoid (version and inclination) and acromion (tilt, coverage, height).
Overall, the scapulae of patients with dynamic and static instability differed only marginally among themselves. Compared with the control group, the glenoid was 2.5° ( = .032), respectively, 5.7° ( = .001) more retroverted and 2.9° ( = .025), respectively, 3.7° ( = .014) more downward tilted in dynamic, respectively, static instability. The acromial roof of dynamic instability was significantly higher and on average 6.2° ( = .007) less posterior covering with an increased posterior acromial height of +4.8mm ( = .001). The acromial roof of static instability was on average 4.8° ( = .041) more externally rotated (axial tilt), 7.3° ( = .004) flatter (sagittal tilt), 8.3° ( = .001) less posterior covered with an increased posterior acromial height of +5.8 mm (0.001).
The scapula of shoulders with dynamic and static posterior instability is characterized by an increased glenoid retroversion and an acromion that is shorter posterolaterally, higher, and more horizontal in the sagittal plane. All these deviations from the normal scapula values were more pronounced in static posterior instability.
有证据表明，肩胛形态的特定变异与动态和静态的肩后部不稳定相关。迄今为止，关于肩胛盂和/或肩峰变异的观察是独立分析的，采用二维成像或未与健康对照组进行比较。因此，本研究的目的是使用三维表面模型和三维测量方法，分析和描述健康肩部以及存在静态或动态肩后部不稳定的肩部的肩胛骨三维形状。
在本研究中，分析了30例单向后向不稳定患者和20例肱骨头静态半脱位患者（静态后向不稳定，Walch B1型）。将这两个队列与40例肩部稳定、无临床症状的对照组患者进行比较。通过对计算机断层扫描图像进行分割获得三维表面模型，并对肩胛盂（版本和倾斜度）和肩峰（倾斜度、覆盖范围、高度）进行三维测量。
总体而言，动态和静态不稳定患者的肩胛骨之间差异仅微乎其微。与对照组相比，在动态不稳定和静态不稳定中，肩胛盂分别多后倾2.5°（P = 0.032）和5.7°（P = 0.001），分别多向下倾斜2.9°（P = 0.025）和3.7°（P = 0.014）。动态不稳定时肩峰顶显著更高，后覆盖平均减少6.2°（P = 0.007），肩峰后高度增加4.8mm（P = 0.001）。静态不稳定时肩峰顶平均外旋（轴向倾斜）多4.8°（P = 0.041），更平坦（矢状倾斜）7.3°（P = 0.004），后覆盖减少8.3°（P = 0.001），肩峰后高度增加5.8mm（P = 0.001）。
存在动态和静态肩后部不稳定的肩部的肩胛骨特征为肩胛盂后倾增加，肩峰在矢状面更短、后外侧更高且更水平。与正常肩胛骨值的所有这些偏差在静态后向不稳定中更为明显。
