Information on measurement properties of translated versions of the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index is still limited. This study investigated the internal consistency, test-retest reliability/agreement, construct validity, and floor and ceiling effects of Portuguese-Brazil WOMAC applied to civil servants at baseline of ELSA-Brasil Musculoskeletal cohort. Each measurement property was evaluated in the overall sample, in the subgroup reporting knee symptoms, and across different sociodemographic strata (except factorial analyses). Separate analyses were performed for pain, stiffness and function dimensions, considering the knee with the worst score (or right knee if same score in both knees). A total of 1740 participants were included (319 completed WOMAC on 2 occasions), mean age 56.0 (standard deviation = 8.9) years, 46.8% male, 42.1% had knee symptoms. In the overall sample, the range of results for WOMAC's dimensions were: internal consistency = cronbach alpha 0.92-0.98; test-retest reliability = intraclass correlation coefficient 0.85-0.97; standard error of measurement (SEM) = 1.38-5.86; smallest detectable change (SDC) = 3.84-16.25; lowest possible score = 38.8%-61.1% (floor effect present); highest possible score = 0.2%-0.9% (ceiling effect absent). Construct validity was confirmed by hypothesis testing and factorial analysis. Results were similar in the symptomatic group, except for higher SEM and SDC, and the absence of floor effects in pain and function dimensions. Portuguese-Brazil WOMAC showed good overall quality in a nonclinical setting. Variability in measurement properties across different strata of the population should be taken into consideration for the design of future studies using WOMAC.

中文翻译：

---

葡萄牙-巴西西部安大略省和麦克马斯特大学的骨关节炎指数（WOMAC）的测量特性，用于评估巴西成年人的膝关节不适：ELSA-巴西肌肉骨骼队列。

关于西安大略省和麦克马斯特大学（WOMAC）骨关节炎指数的翻译版本的测量属性的信息仍然有限。这项研究调查了葡萄牙-巴西WOMAC在ELSA-巴西肌肉骨骼队列的基础上应用于公务员的内部一致性，重测信度/协议，结构效度以及地板和天花板效应。在总体样本中，报告膝盖症状的亚组中以及在不同的社会人口统计学层次（因子分析除外）中评估了每种测量属性。针对疼痛，僵硬和功能尺寸进行了单独的分析，考虑到得分最差的膝盖（如果两个膝盖的得分相同，则为右膝）。总共包括1740名参与者（两次完成319次WOMAC），平均年龄56.0（标准差= 8）。9）岁，男性46.8％，有膝盖症状的42.1％。在整个样本中，WOMAC尺寸的结果范围为：内部一致性= cronbach alpha 0.92-0.98；重测信度=组内相关系数0.85-0.97; 标准测量误差（SEM）= 1.38-5.86；最小可检测变化（SDC）= 3.84-16.25; 最低可能得分= 38.8％-61.1％（存在地板效果）；最高可能得分= 0.2％-0.9％（无天花板效果）。通过假设检验和因子分析来确认构建体的有效性。有症状组的结果相似，但SEM和SDC较高，并且在疼痛和功能范围上没有地板效应。葡萄牙语-巴西WOMAC在非临床环境中显示出良好的整体质量。