Cross-cultural adaptation of the lower extremity functional scale in kannada and assessment of its measurement properties – a longitudinal study

Background: Lower Extremity Functional Scale (LEFS) is a useful tool for evaluating lower extremity (LE) disability, but it has not been adapted for use with Kannada or other regional languages in India. Objective: This study aimed to perform cross-cultural adaptation and Kannada translation of the LEFS (LEFS-K) and examine its psychometric properties. Methods: A Longitudinal study on 150 patients with hip and knee injuries. Numeric Rating Scales for Pain (NRS-P) and disability (NRS-D), and Sit-to-stand (5STS) was administered at the initial visit. LEFS-K and NRS again 2 days later and at discharge. Intraclass correlation coefficient (ICC) and Cronbach's alpha (CA) assessed test-retest reliability and internal consistency. Pearson correlation coefficients (r) examined concurrent relations. Effects size was calculated for responsiveness. Clinically important (MCID) and statistically true (MDC) were assessed for the LEFS-K. Results: LEFS-K demonstrated excellent test-retest reliability (ICC = 0.98) and internal consistency (CA = 0.88). Low to moderate correlations (r < 0.70) were observed between the LEFS-K and other measures (NRS-P, NRS-D, and 5STS). The LEFS-K was deemed responsive to assess change for LE disability (ES = 0.84). Conclusion: The Kannada LEFS is proved to be a reliable, valid and responsive tool for evaluating LE MSK disability in Kannada speaking individuals with hip and knee disorders.