Translation, Cross-Cultural Adaptation of the Lower Extremity Functional Scale into Filipino, and Analysis of its Psychometric Properties: A Study Protocol

Background: Impairment and functional limitations from musculoskeletal conditions are evaluated using outcome measure tools. The Lower Extremity Functional Scale (LEFS) is one of the outcome measure tools (OMT) that assess the functional capacity of patients who have lower extremity conditions. It was originally developed in English and translated later into other languages; however, no Filipino version is available. Objective: This study aims to translate, cross-culturally adapt the LEFS into Filipino, and evaluate its psychometric properties. Methods: Using a psychometric study design, the LEFS will be translated and cross-culturally adapted into Filipino following the guidelines set by Beaton et al. and Sousa and Rojjanasrirat. These include six stages: (1) forward translation into Filipino, (2) synthesis, (3) backward translation, (4) expert committee review, (5) pilot testing/cognitive interview, and (6) psychometric testing. Filipinos with lower extremity conditions will be recruited for the pilot (n= 10) and psychometric testing (n= 200). Validity will be evaluated using face validity index, content validity index, independent t-test (knowngroup validity), and Spearman rho (concurrent validity). Reliability will be assessed using Cronbach alpha for the internal consistency and intraclass correlation coefficient for the stability. Floor and ceiling effects will also be computed. Expected results: The LEFS will be successfully translated and cross-culturally adapted into Filipino. It will be a valid and reliable outcome measure tool that physical therapists and other healthcare professionals can use for the functional assessment of patients. This study can also serve as a reference for future translation studies.