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

Abstract

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. 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). 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. 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. 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.