Department of Orthopaedics & Orthopaedic Surgery, Saarland University, Kirrberger Strasse 100, 66421, Homburg, Germany.
Department of Orthopaedics & Traumatology, University of Duisburg-Essen, Essen, Germany.
Eur J Med Res. 2020 Dec 10;25(1):67. doi: 10.1186/s40001-020-00469-4.
The recently described 'critical trochanter angle' (CTA) is a novel parameter in the preoperative risk assessment of stem malalignment in total hip arthroplasty. As its reproducibility needs to be evaluated, the given study aims to investigate intra- and interobserver reliability. It is hypothesized that both analyses justify the clinical use of the CTA.
A total of 100 pelvic radiographs obtained prior to total hip arthroplasty were retrospectively reviewed by four observers with different levels of clinical experience. The CTA was measured twice by each observer at different occasions in the previously described technique. Intra- and interobserver reliability was evaluated using intraclass correlation coefficients (ICC) with confidence intervals (CI) and the Bland-Altman approach.
The mean CTA in both measuring sequences was 20.58° and 20.78°. The observers' means ranged from 17.76° to 25.23°. Intraobserver reliability showed a mean difference of less than 0.5° for all four observers (95% limit of agreement: - 7.70-6.70). Intraobserver ICCs ranged from 0.92 to 0.99 (CI 0.88-0.99). For interobserver variation analysis, ICCs of 0.83 (CI 0.67-0.90) and 0.85 (CI 0.68-0.92) were calculated.
Analyses concerning intra- and interobserver reliability in the assessment of the CTA showed 'very good' and 'good' results, respectively. In view of these findings, the use of the CTA as an additional preoperative parameter to assess the risk of intraoperative stem malalignment seems to be justified.
最近描述的“临界转距角（CTA）”是全髋关节置换术术中股骨对线不良术前风险评估的一个新参数。由于其重现性需要进行评估，因此本研究旨在调查其观察者内和观察者间的可靠性。假设这两种分析都证明了 CTA 的临床应用是合理的。
回顾性分析了 100 例全髋关节置换术前的骨盆 X 线片，由 4 名具有不同临床经验水平的观察者进行分析。按照先前描述的技术，每位观察者在不同的场合对 CTA 进行了两次测量。采用组内相关系数（ICC）及其置信区间（CI）和 Bland-Altman 方法评估观察者内和观察者间的可靠性。
两次测量序列的平均 CTA 分别为 20.58°和 20.78°。观察者的平均值范围为 17.76°至 25.23°。所有 4 名观察者的观察者内可靠性差异均值均小于 0.5°（95%一致性区间：-7.70-6.70）。观察者内 ICC 范围为 0.92 至 0.99（CI 0.88-0.99）。对于观察者间变异分析，计算得出的 ICC 分别为 0.83（CI 0.67-0.90）和 0.85（CI 0.68-0.92）。
在评估 CTA 的观察者内和观察者间可靠性的分析中，分别得到了“非常好”和“良好”的结果。鉴于这些发现，将 CTA 作为评估术中股骨对线不良风险的附加术前参数似乎是合理的。
