From the Department of Orthopedics and Traumatology, Clinica Alemana de Santiago (Dr. Vaisman, Dr. Schmidt-Hebbel, Dr. Guiloff, Dr. Valderrama, Dr. Arellano, Dr. Edwards, Dr. Rotman, Dr. Calvo, and Dr. Figueroa), Faculty of Medicine, Clinica Alemana de Santiago-Universidad del Desarrollo (Dr. Vaisman, Dr. Schmidt-Hebbel, Dr. Arellano, Dr. Edwards, Dr. Calvo, and Dr. Figueroa), and the Department of Radiology, Clinica Alemana de Santiago (Dr. Zilleruelo), Santiago, Chile.
J Am Acad Orthop Surg Glob Res Rev. 2020 Jul;4(7):e2000098. doi: 10.5435/JAAOSGlobal-D-20-00098.
Validity and reproducibility of the clinician's eye (CE) to diagnose patella alta (PA) on a lateral knee radiography (radiograph) is unknown.
Cross-sectional study of 46 lateral knee x-rays. Three blind observers used CE, Insall-Salvati (IS), modified Insall-Salvati (mIS), and Caton-Deschamps (C-D) to determine patellar height. Sensitivity and specificity of each observer was compared with the musculoskeletal radiologist's C-D measurements. Intraobserver and interobserver agreement were assessed with intraclass correlation coefficient and Fleiss κ, respectively. Time needed to estimate patellar height for every method was recorded in seconds. Statistical differences between observers were calculated with a generalized estimating equation. Analysis of variance and post hoc Bonferroni test compared duration of each method (P < 0.05). Data were analyzed using Stata 15 (StataCorp).
CE, IS, mIS, and C-D's sensitivity and specificity values are as follows: 77%, 92%; 94%, 52%; 67%, 58%; and 53%, 89%, respectively. Intraclass correlation coefficient and Fleiss κ of CE, IS, mIS, and C-D values are as follows: 0.66 and 0.43, 0.88 and 0.68, 0.54 and 0.09, and 0.68 and 0.59, respectively. CE was the second most sensitive and most specific method for diagnosis of PA, with moderate intraobserver and interobserver agreement. IS was the most sensitive method with good intraobserver and interobserver agreement. CE was significantly faster (P < 0.05) than all other conventional radiographic ratios.
CE's sensitivity increases with observer's experience and is highly specific. If normal patellar height is diagnosed, no other ratios are necessary, even in the less experienced clinician. Intraobserver and interobserver reproducibilities were moderate and only inferior to the IS ratio. In case patellar height is uncertain with the CE, the IS ratio is the most sensitive and reproducible method to confirm the diagnosis of PA.
临床医生通过侧位膝关节 X 线片（X 光片）诊断髌骨高位（PA）的准确性和可重复性尚不清楚。
对 46 例侧位膝关节 X 线片进行横断面研究。三位盲法观察者使用临床医生目测（CE）、Insall-Salvati（IS）、改良 Insall-Salvati（mIS）和 Caton-Deschamps（C-D）来确定髌骨高度。将每位观察者的敏感性和特异性与肌肉骨骼放射科医生的 C-D 测量结果进行比较。分别使用组内相关系数和 Fleiss κ 评估观察者内和观察者间的一致性。记录每种方法估计髌骨高度所需的时间（以秒为单位）。使用广义估计方程计算观察者之间的统计学差异。方差分析和事后 Bonferroni 检验比较了每种方法的持续时间（P < 0.05）。使用 Stata 15（StataCorp）进行数据分析。
CE、IS、mIS 和 C-D 的敏感性和特异性值分别为：77%、92%；94%、52%；67%、58%和 53%、89%。CE、IS、mIS 和 C-D 值的组内相关系数和 Fleiss κ 分别为：0.66 和 0.43、0.88 和 0.68、0.54 和 0.09 和 0.68 和 0.59。CE 是诊断 PA 第二敏感和最特异的方法，观察者内和观察者间的一致性为中等。IS 是最敏感的方法，具有良好的观察者内和观察者间的一致性。CE 明显更快（P < 0.05），与所有其他常规放射比值相比。
CE 的敏感性随着观察者经验的增加而增加，并且具有高度的特异性。如果诊断出正常的髌骨高度，则无需进行其他比值检查，即使是经验较少的临床医生也是如此。观察者内和观察者间的可重复性为中等，仅低于 IS 比值。如果 CE 对髌骨高度不确定，则 IS 比值是最敏感和可重复的方法来确认 PA 的诊断。
