Translation, cross-cultural adaptation and validation of the Turkish version of the Lower Extremity Functional Scale on patients with knee injuries

Introduction The Lower Extremity Functional Scale is a widely used questionnaire to evaluate the functional impairment in lower extremities. To date, the Lower Extremity Functional Scale has not been translated into Turkish. The aim of this study is to translate and culturally adapt the Lower Extremity Functional Scale into a Turkish version, and evaluate the psychometric properties of this version in patients with knee injuries. Materials and methodsThe translation of the English version of the Lower Extremity Functional Scale into a Turkish version was performed using standard guidelines. Validity and reliability of Turkish version were tested in 134 patients with knee injuries. Association level between other outcomes measures (Kujala Patellofemoral Score, the Western Ontario and McMaster Universities Osteoarthritis Index, Lysholm Knee Scoring Scale and a Visual Analog Scale) and Turkish version of the Lower Extremity Functional Scale was analyzed to assess validation. Participants completed the questionnaire at baseline and after 2 days to test reliability. ResultsThe Turkish version of the Lower Extremity Functional Scale was showed a high degree of internal consistency (Cronbach alpha = 0.93). ICCs were 0.96 and no floor or ceiling effects. The Lower Extremity Functional Scale had a high level of association with the Kujala Patellofemoral Score (r = 0.82), Lysholm Knee Scoring Scale (r = 0.80) and the Western Ontario and McMaster Universities Osteoarthritis Index scores (r = 0.69) (all, p < 0.05). ConclusionThe Turkish version of the Lower Extremity Functional Scale is a valid and reliable questionnaire that can be used to evaluate functional status in Turkish speaking patients with different knee disorders.