Abstract
Purpose: To examine the measurement properties of the 15-item Arabic Lower Extremity Functional Scale (LEFS-Ar) in patients with lower extremity musculoskeletal disorders Materials and Methods: Patients with lower extremity musculoskeletal disorders (N = 116) completed the 15-item LEFS-Ar, Global Assessment of Function, RAND 36-item Health Survey, and Numeric Pain Rating Scale. A subset of participants completed a retest session within 2 to 7 days that also involved completion of the Global Rating of Change Scale. Internal consistency, test-retest reliability, measurement error, floor and ceiling effects of 15-item LEFS-Ar were examined. Construct validity was also tested by examining a number of predefined hypotheses regarding expected correlation between the 15-item LEFS-Ar and the other measures. Results: The 15-item Arabic LEFS had excellent internal consistency (Cronbach's alpha= 0.93) and excellent test-retest reliability (ICC (agreement )= 0.95) with no floor or ceiling issues. The standard error of measurement of the Arabic 15-item Arabic LEFS was 2.71 points while the minimal detectable change was 7.51 points. Eighty-three percent of the predefined construct validity correlational hypotheses were supported by the results of the study justifying the construct validity of the 15-item LEFS-Ar. Conclusion: The 15-item LEFS-Ar demonstrated evidence supporting its internal consistency, test-retest reliability and construct validity as a measure of lower extremity function in Arabic-speaking patients with lower extremity musculoskeletal disorders.