Reliability and validity of the Persian lower extremity functional scale (LEFS) in a heterogeneous sample of outpatients with lower limb musculoskeletal disorders.

PURPOSE: The aim was to culturally translate and validate the Persian lower extremity functional scale (LEFS) in a heterogeneous sample of outpatients with lower extremity musculoskeletal disorders (n = 304).

METHOD: This is a prospective methodological study. After a standard forward-backward translation, psychometric properties were assessed in terms of test-retest reliability, internal consistency, construct validity, dimensionality, and ceiling or floor effects.

RESULTS: The acceptable level of intraclass correlation coefficient >0.70 and Cronbach's alpha coefficient >0.70 was obtained for the Persian LEFS. Correlations between Persian LEFS and Short-Form 36 Health Survey (SF-36) subscales of Physical Health component (rs range = 0.38-0.78) were higher than correlations between Persian LEFS and SF-36 subscales of Mental Health component (rs range = 0.15-0.39). A corrected item--total correlation of >0.40 (Spearman's rho) was obtained for all items of the Persian LEFS. Horn's parallel analysis detected a total of two factors. No ceiling or floor effects were detected for the Persian LEFS.

CONCLUSIONS: The Persian version of the LEFS is a reliable and valid instrument that can be used to measure functional status in Persian-speaking patients with different musculoskeletal disorders of the lower extremity. Implications for Rehabilitation The Persian lower extremity functional scale (LEFS) is a reliable, internally consistent and valid instrument, with no ceiling or floor effects, to determine functional status of heterogeneous patients with musculoskeletal disorders of the lower extremity. The Persian version of the LEFS can be used in clinical and research settings to measure function in Iranian patients with different musculoskeletal disorders of the lower extremity.