Aydin Özgür, Hapa Onur, Acar Emre, Celtik Mustafa, Agca Selahattin, Turemis Cihangir, Yarol Raif C, Aydemir Selahaddin
Department of Orthopaedic Surgery, Faculty of Medicine, Dokuz Eylul University, İnciralti, Mithatpasa St. No:56 Balcova, Izmir 35330, Turkey.
Department of Orthopaedic Surgery, Dr. Abdurrahman Yurtaslan Oncology Training and Research Hospital, Demetevler, 354/1. St., Yenimahalle, Ankara 06200, Turkey.
J Hip Preserv Surg. 2025 Jan 30;12(2):134-138. doi: 10.1093/jhps/hnaf006. eCollection 2025 Jul.
The alpha angle is a radiological measurement that has been proposed for the detection of cam morphology in patients suspected of femoroacetabular impingement syndrome (FAIS). After analysing published articles on FAIS, it is apparent that different types of circles are used in the measurement of alpha angles. To determine the interobserver and intraobserver reliability of alpha angle values measured using different types of circles on a 45° Dunn lateral radiograph in patients with symptomatic FAIS. The 45° Dunn lateral radiographs of the operated hips of patients who underwent hip preservation surgery in Dokuz Eylül University Hospital between 2014 and 2017 were evaluated retrospectively. Alpha angles were measured manually with transparent goniometers using three different circle types: thin full circle, thin-dashed circle, and thick full circle, and eye estimation without circle insertion. Measurements were made separately by an orthopaedist and a radiologist. A second measurement was made by the radiologist 1 month later for intraobserver reliability. Interobserver reliability for the thin full circle, thin-dashed circle, thick circle, and eye estimation (ICC = 0.645, 0.525, 0.494, and 0.588, respectively). Intraobserver reliability for the thin, thin-dashed, thick line, and eye estimation (ICC= 0.626, 0.681, 0.681, and 0.462 respectively). Interobserver difference of mean values of alpha angles for thin full, thin-dashed, thick full, and eye estimation were 2.7°, 0.9°, 1.1°, and 2.3°, respectively. Intraobserver differences between measurements were 1.5°, 0.9°, 0°, and 1.6°, respectively. Our study demonstrated that interobserver reliability is highest when measurements are made using a thin full circle.
α角是一种影像学测量指标，已被用于疑似股骨髋臼撞击综合征（FAIS）患者凸轮形态的检测。在分析了关于FAIS的已发表文章后，很明显在α角测量中使用了不同类型的圆。目的是确定在有症状的FAIS患者的45°邓氏侧位X线片上，使用不同类型的圆测量α角值时的观察者间和观察者内可靠性。回顾性评估了2014年至2017年在多库兹艾吕尔大学医院接受保髋手术患者的手术髋关节的45°邓氏侧位X线片。使用透明量角器手动测量α角，使用三种不同类型的圆：细全圆、细虚线圆和粗全圆，以及不插入圆的目测估计。测量由一名骨科医生和一名放射科医生分别进行。放射科医生在1个月后进行第二次测量以评估观察者内可靠性。细全圆、细虚线圆、粗圆和目测估计的观察者间可靠性（组内相关系数分别为0.645、0.525、0.494和0.588）。细、细虚线、粗线和目测估计的观察者内可靠性（组内相关系数分别为0.626、0.681、0.681和0.462）。细全圆、细虚线圆、粗全圆和目测估计的α角平均值的观察者间差异分别为2.7°、0.9°、1.1°和2.3°。测量之间的观察者内差异分别为1.5°、0.9°、0°和1.6°。我们的研究表明，使用细全圆进行测量时观察者间可靠性最高。
