The epiphyseal height and metaphyseal width ratio estimated lateral pillar involvement with limited generalizability among various interpreters. The aim of the study was to evaluate the reliability and the validity of height–width ratio measurement in Perthes disease among interpreters of different experience levels. A cross-sectional study was conducted between 2019 and 2020. We included four groups of interpreters: orthopaedic residents, orthopaedic fellows, radiology residents and radiology fellows who were unaware of radiographic study materials. Each interpreter blindedly evaluated Perthes hip radiographs twice at 1-month intervals using the height–width ratio method. Patients’ and interpreters’ characteristics, height–width ratio and height–width ratio converted to lateral pillar classification (A, B and C) were collected. Intra- and interobserver reliability validated with the paediatric orthopaedist were estimated. Twenty-four interpreters assessed 18 Perthes radiographs. Intraobserver level of agreement (95% confidence interval) for height–width ratio was 0.022 (−0.017 to 0.062), −0.027 (−0.074 to 0.019), −0.010 (−0.095 to 0.074) and 0.019 (−0.109 to 0.146); and interobserver reliability compared with the paediatric orthopaedist was −0.007 (−0.091 to 0.077), 0.003 (−0.056 to 0.061), −0.021 (−0.077 to 0.035) and −0.002 (−0.090 to 0.086) for orthopaedic residents and fellows, radiology residents and fellows, respectively. Kappa statistics of height–width ratio converting to lateral pillar classification indicated intraobserver agreement of orthopaedic residents and fellows, radiology residents and fellows was 0.83, 0.75, 0.54 and 0.91; and interobserver agreement compared with the paediatric orthopaedist was 0.92, 0.83, 0.42 and 0.83, orderly. Height-width ratio and lateral pillar estimation by orthopaedic and radiology trainees have moderate to excellent reliability. Level of evidence: Level II – diagnostic study.

骨骺高度和干骺端宽度比估计侧柱受累，但在各种解释器中的普遍性有限。该研究的目的是评估信度和效度不同经验水平口译员 Perthes 病高宽比测量的研究 在 2019 年至 2020 年期间进行了一项横断面研究。我们包括四组口译员：骨科住院医师、骨科研究员、放射科住院医师和不了解放射学研究材料的放射科医师。每位口译员每隔 1 个月使用高宽比方法对 Perthes 髋部 X 光片进行两次盲法评估。收集患者和口译员的特征、高宽比和高宽比转换为侧柱分类（A、B 和 C）。评估了儿科骨科医生验证的观察者内部和观察者间的可靠性。24 名口译员评估了 18 张 Perthes 射线照片。高宽比的观察者内部一致性水平（95% 置信区间）为 0.022（-0.017 至 0.062）、-0.027（-0.074 至 0.019）、-0.010（-0.095 至 0.074）和 0.019（-0.109 至 0.146）；与儿科骨科医生相比，观察者间的可靠性分别为 -0.007（-0.091 至 0.077）、0.003（-0.056 至 0.061）、-0.021（-0.077 至 0.035）和 -0.002（-0.090 至 0.086）居民和研究员，分别。高宽比转换为侧柱分类的 Kappa 统计表明，骨科住院医师和研究员、放射科住院医师和研究员的观察者内一致性分别为 0.83、0.75、0.54 和 0.91；与小儿骨科医师相比，观察者间一致性分别为0.92、0.83、0.42和0.83，有序。骨科和放射科学员的高宽比和侧柱估计具有中等至极好的可靠性。证据级别：II 级——诊断性研究。