Construct validity, test–retest reliability, and responsiveness of the Arabic version of the upper limb functional index

BACKGROUND: The upper limb functional index (ULFI) is a widely used self-report outcome measure questionnaire with robust psychometric properties to assess the upper limb musculoskeletal disorders (UL-MSDs). This study aimed to investigate the psychometric properties of the Arabic version of ULFI (ULFI-Ar). METHODS: In this observational study, 139 patients (87 male, 52 females with mean age of 38.67 ± 13.04 year) with various UL-MSD’s, completed the ULFI-Ar, Disability of Arm, Shoulder, and Hand questionnaire (DASH-Arabic), and numeric pain rating scale (NPRS-Arabic). All participants determined the factor structure, and the construct validity. A subgroup of the participants determined test–retest reliability (n = 46) and responsiveness (n = 27). RESULTS: The ULFI-Ar construct validity obtained by the expletory factor analysis as one-factor structure, demonstrated an excellent test–retest reliability [intraclass correlation coefficient (ICC(2:1)) = 0.95], measurement error [standard error of measurement (SEM) = 4.43%; minimal detectable change at 90% confidence interval (MDC(90)) = 10.34%], medium internal responsiveness [Cohen’s d = 0.62 and standard response of mean (SRM) = 0.67], strong external responsiveness DASH-Arabic (r =—0.90; p < 0.001), and negative strong correlation with NPRS-Arabic (r =—0.75, p < 0.001). CONCLUSIONS: The ULFI-Ar is a valid, reliable, and responsive self-report questionnaire to assess UL-MSDs in Arabic speaking patients.