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

Abstract

To translate and culturally adapt the LEFS into European Portuguese and evaluate its measurement properties in adults with lower limb musculoskeletal disorders. The LEFS was translated and adapted following international guidelines. A total of 105 participants completed the LEFS, SF-36 and baseline form; 80 repeated the LEFS after 48-72 h. Structural validity was assessed by confirmatory factor analysis. Internal consistency, test-retest reliability, measurement error, floor/ceiling effects and construct validity through a priori hypothesis testing were evaluated. Cross-cultural adaptation supported conceptual, semantic and operational equivalence. Structural validity was mixed: one-factor and correlated two-factor models met the SRMR criterion, whereas other fit indices were suboptimal. Internal consistency was adequate (α = .984), and test-retest reliability was good (ICC = .970; weighted kappa = .769-.956). SEM was 4.17 and SDC was 11.56. Floor and ceiling effects were minimal (2.9% and 0%). Construct validity hypotheses were confirmed, with strongest correlations between LEFS and SF-36 Physical Functioning (ρ = .916 total; .555 acute; .812 chronic). The European Portuguese LEFS showed adequate internal consistency, good test-retest reliability, acceptable measurement error and evidence supporting construct validity; structural validity should be interpreted cautiously.