Pontes-Silva André, Dibai-Filho Almir Vieira, Pires Flávio de Oliveira, Girasol Carlos Eduardo, Araujo Gabriel Gardhel Costa, Leal Plínio da Cunha, Arrais Junior José Djalma, Fidelis-de-Paula-Gomes Cid André, Cabido Christian Emmanuel Torres
Departamento de Fisioterapia, Programa de Pós-Graduação em Fisioterapia, Universidade Federal de São Carlos (UFSCar), São Carlos (SP), Brazil.
Departamento de Educação Física, Programa de Pós-Graduação em Educação Física, Universidade Federal do Maranhão (UFMA), São Luís (MA), Brazil.
Sao Paulo Med J. 2025 Jun 27;143(5):e2024153. doi: 10.1590/1516-3180.2024.0153.R1.07032025. eCollection 2025.
To assess the Functional Index Questionnaire (FIQ) structure using confirmatory factor analysis (CFA) in Brazilian patients with anterior knee pain.
Brazilian patients of both sexes (n = 100), aged ≥ 18 years, with anterior knee pain for at least 3 months were included. Eligible participants completed an online form that collected personal and clinical data as well as responses to the assessment tools. We used CFA and the following fit indices: chi-square/degrees of freedom (DF), comparative fit index (CFI), Tucker-Lewis index (TLI), root mean square error of approximation (RMSEA), and standardized root mean square residuals (SRMR).
The majority of the respondents were women, young adults, overweight, with incomplete higher education, were physically active, and had pain in sitting or squatting positions. The mean duration of pain was 38.24 months, and the mean pain intensity was 4.54 points. The model fit indices were as follows: χ2/DF = 2.08, TLI = 0.978, CFI = 0.969, RMSEA = 0.104, and SRMR = 0.077. Therefore, the one-dimensional structure with eight items yielded an RMSEA value above the 0.08 cutoff point, suggesting a poorer fit and more residual error than is acceptable for a well-fitting model. Using the modification indices within the CFA, we observed a correlation between Items 2 (climbing up two flights of stairs [16 steps]) and 6 (climbing up four flights of stairs [32 steps]) and Items 3 (squatting) and 4 (kneeling), indicating the similarity in the response pattern for these items. After adding these correlations to the model, we obtained improved fit indices (χ2/DF = 1.51, TLI = 0.990, CFI = 0.985, RMSEA = 0.072, and SRMR = 0.061).
This version of the FIQ should be used with caution, as the unidimensional model demonstrates substantial residuals, mainly because of item redundancy.
采用验证性因子分析（CFA）评估巴西前膝痛患者的功能指数问卷（FIQ）结构。
纳入年龄≥18岁、前膝痛至少3个月的巴西男女患者（n = 100）。符合条件的参与者填写一份在线表格，收集个人和临床数据以及对评估工具的回答。我们使用CFA和以下拟合指数：卡方/自由度（DF）、比较拟合指数（CFI）、塔克-刘易斯指数（TLI）、近似均方根误差（RMSEA）和标准化均方根残差（SRMR）。
大多数受访者为女性、年轻成年人、超重、高等教育未完成、身体活跃，且在坐姿或蹲姿时疼痛。疼痛平均持续时间为38.24个月，平均疼痛强度为4.54分。模型拟合指数如下：χ2/DF = 2.08，TLI = 0.978，CFI = 0.969，RMSEA = 0.104，SRMR = 0.077。因此，包含八个条目的一维结构产生的RMSEA值高于0.08的截断点，表明拟合较差且残差误差比拟合良好的模型可接受的范围更大。使用CFA中的修正指数，我们观察到条目2（爬上两层楼梯[16级台阶]）和条目6（爬上四层楼梯[32级台阶]）以及条目3（下蹲）和条目4（跪姿）之间存在相关性，表明这些条目的反应模式相似。将这些相关性添加到模型中后，我们获得了改进的拟合指数（χ2/DF = 1.51，TLI = 0.990，CFI = 0.985，RMSEA = 0.072，SRMR = 0.061）。
该版本的FIQ应谨慎使用，因为一维模型显示出大量残差，主要是由于条目冗余。
