College of Medicine, Medical University of South Carolina, Charleston, South Carolina, U.S.A.
Department of Orthopaedics and Physical Medicine, Medical University of South Carolina, Charleston, South Carolina, U.S.A.
Arthroscopy. 2021 Jan;37(1):17-25. doi: 10.1016/j.arthro.2020.09.014. Epub 2020 Sep 19.
To determine whether change in shoulder position between internal rotation (IR) and external rotation (ER) during magnetic resonance arthrography (MRA) affects previously defined capsular measurements and to determine the utility of rotation in the diagnosis of instability.
A retrospective study was conducted of patients who received a shoulder MRA with humeral IR and ER views. Patients with an arthroscopically confirmed diagnosis of instability and those with clinically stable shoulders, no history of instability, and no MRA findings of instability were identified and compared. Humeral rotation, glenoid retroversion, humeral head subluxation, capsular length, and capsular area using axial sequences of IR and ER views were recorded. Analysis compared IR, ER, and Δ capsular measurements between groups using independent t tests and univariate and multivariate regression.
Thirty-one subjects who were diagnosed with instability were included, along with 28 control subjects. Capsular length, capsular area, and humeral subluxations were significantly greater with ER compared with IR views (P < .001, P < .001, P < .001). Patients with instability displayed greater ER capsular length (P = .0006) and ER capsular area (P = .005) relative to controls. Multivariate logistic regression identified age, weight, sex, ER capsular length, and retroversion to be significant predictors of instability. ER capsular length independently predicts instability with 86% sensitivity and 84% specificity. Interobserver reliability using the intraclass correlation coefficient was rated good or excellent on all measurements.
Variance in humeral rotation during shoulder MRA significantly affects capsular measurements. Rotational views increase the utility of capsular measurements when assessing for instability, particularly capsular length and capsular area. The implementation of ER positioning enhances the ability to examine capsular changes of the shoulder joint and can assist in the diagnosis of instability.
III, retrospective comparative study.
确定磁共振关节造影（MRA）过程中肩关节内旋（IR）和外旋（ER）时的位置变化是否会影响先前定义的囊袋测量值，并确定旋转在诊断不稳定中的作用。
对接受肩关节 MRA 检查并同时获得 IR 和 ER 视图的患者进行回顾性研究。确定并比较了经关节镜证实不稳定和临床稳定、无不稳定病史且 MRA 无不稳定发现的患者。记录了 IR 和 ER 轴位序列的肱骨头旋转、关节盂后倾、肱骨头半脱位、囊袋长度和囊袋面积。使用独立 t 检验和单变量及多变量回归比较了各组之间的 IR、ER 和 Δ囊袋测量值。
共纳入 31 例诊断为不稳定的患者和 28 例对照患者。与 IR 视图相比，ER 视图下囊袋长度、囊袋面积和肱骨头半脱位明显更大（P<0.001，P<0.001，P<0.001）。与对照组相比，不稳定患者的 ER 囊袋长度（P=0.0006）和 ER 囊袋面积（P=0.005）更大。多元逻辑回归确定年龄、体重、性别、ER 囊袋长度和后倾是不稳定的显著预测因子。ER 囊袋长度具有 86%的敏感性和 84%的特异性，是不稳定的独立预测因子。使用组内相关系数评估所有测量值的观察者间可靠性均为良好或优秀。
肩关节 MRA 过程中肱骨头旋转的差异会显著影响囊袋测量值。旋转视图增加了在评估不稳定时囊袋测量值的实用性，尤其是囊袋长度和囊袋面积。实施 ER 定位增强了检查肩关节囊袋变化的能力，并有助于诊断不稳定。
III 级，回顾性比较研究。
