Cross-cultural adaptation, validity and reliability of the Arabic version of the Lower Extremity Functional Scale

Abstract

Purpose: The aim was to translate and cross-culturally adapt the Lower Extremity Functional Scale (LEFS) into Arabic language and to examine its measurement properties in patients with musculoskeletal disorders of the lower extremity. Methods: Standard forward and backward translation followed by expert committee review, then preliminary testing was carried out to produce the final Arabic version of LEFS (LEFS-Ar). The test-retest reliability, measurement error, internal consistency and construct validity of the LEFS-Ar were examined in patients with musculoskeletal disorders of the lower extremity (N = 116). Results: The LEFS-Ar had excellent test-retest reliability (ICC2,1 = 0.96). LEFS-Ar standard error of measurement was 3.5 points while the minimal detectable change MDC95 was 9.8 points. LEFS-Ar showed excellent internal consistency with Cronbach's alpha of 0.95. Parallel analysis and factor analysis showed that LEFS-Ar measures one underlying factor with all items loading heavily on this single factor. LEFS-Ar showed significant positive correlation with patient's global assessment of function (r = 0.59) and that patients recovering from surgery reported lower LEFS-Ar score compared to patients with no surgery further supporting the construct validity of the LEFS-Ar. Conclusion: LEFS-Ar has excellent internal consistency, test-retest reliability with relatively small measurement error and is a valid measure of activity limitation due to lower extremity musculoskeletal disorders. All these measurement properties of the LEFS-Ar suggest the clinical usefulness of this measure. ▸ Implications for Rehabilitation • The Arabic Lower Extremity Functional Scale (LEFS-Ar) is a reliable and valid measure of activity limitation due to lower extremity musculoskeletal disorders with relatively small measurement error. • LEFS-Ar can be used in daily clinical practice and for research purposes to quantify activity limitation in Arabic-speaking individuals with lower extremity musculoskeletal disorders.