Tuite M J, Toivonen D A, Orwin J F, Wright D H
Department of Radiology, University of Wisconsin Clinical Science Center, Madison 53792-3252, USA.
AJR Am J Roentgenol. 1995 Sep;165(3):609-13. doi: 10.2214/ajr.165.3.7645479.
This study was undertaken to determine the reproducibility of measurements of an acromial angle on radiographs and to correlate those measurements with the presence of the impingement syndrome and rotator cuff tears.
Ninety-nine shoulders in 95 patients who had an arch radiograph and had undergone shoulder arthroscopy were included in this retrospective study. The acromial angle was measured on the arch view of the shoulder independently by three observers who were blinded to the name, history, and arthroscopic results. The angle was measured at the intersection of lines drawn along the inferior cortex of the anterior and posterior portions of the acromion. Interobserver variability was determined by the intercorrelation coefficient (a test of reproducibility of quantitative measurements). The average of the three measurements for each patient was correlated with the preoperative diagnosis and the arthroscopic findings.
A correlation was found between increasing severity of cuff disease as determined on arthroscopy and increasing acromial angle (p < .01). In 67 patients (70 shoulders) with impingement, patients with a full-thickness tear (29%) accounted for 43% of those with an angle of 30 degrees or greater. The average acromial angle for patients with impingement was greater than that for either patients with instability or patients with trauma (p < .05 for both). An angle of 25 degrees or greater was measured in 63% of patients with impingement but in only 18% of those with instability. The average acromial angle in patients with impingement and an intact rotator cuff was also greater than the average angle in patients with instability (p = .001). The interobserver variability had an intercorrelation coefficient of 0.90.
The acromial angle is an objective and fairly reproducible measure of anterior acromial shape. The angle is useful in identifying patients with a greater likelihood of having a rotator cuff tear and in distinguishing patients with primary impingement from those with instability.
本研究旨在确定X线片上肩峰角测量的可重复性，并将这些测量结果与撞击综合征和肩袖撕裂的存在情况相关联。
本回顾性研究纳入了95例患者的99个肩部，这些患者均有肩关节X线片且接受了肩关节镜检查。由三名对患者姓名、病史和关节镜检查结果不知情的观察者独立在肩关节X线正位片上测量肩峰角。该角度在沿肩峰前后部下缘绘制的线的交点处测量。观察者间的变异性通过组内相关系数来确定（定量测量可重复性的检验）。将每位患者三次测量的平均值与术前诊断和关节镜检查结果相关联。
关节镜检查确定的肩袖疾病严重程度增加与肩峰角增大之间存在相关性（p < 0.01）。在67例（70个肩部）有撞击的患者中，全层撕裂患者（29%）占角度为30度或更大患者的43%。有撞击患者的平均肩峰角大于不稳定或创伤患者（两者p < 0.05）。63%有撞击的患者测量角度为25度或更大，而不稳定患者中这一比例仅为18%。有撞击且肩袖完整的患者的平均肩峰角也大于不稳定患者的平均角度（p = 0.001）。观察者间变异性的组内相关系数为0.90。
肩峰角是肩峰前部形状的一种客观且相当可重复的测量指标。该角度有助于识别肩袖撕裂可能性较大的患者，并区分原发性撞击患者与不稳定患者。
