Cross-cultural adaption and validation of simplified Chinese version of the lower extremity function scale in patients with knee osteoarthritis

Introduction The lower extremity function scale (LEFS) is widely used to investigate patients' functional status due to musculoskeletal dysfunction of the lower extremity. The aims of this study were to translate and cross-culturally adapt the LEFS into simplified Chinese (SC-LEFS) and evaluate the psychometric properties in patients with knee osteoarthritis (OA). Methods The SC-LEFS was translated and cross-culturally adapted on the basis of guideline. Patients scheduled for knee arthroplasty (108) were invited in this study. The Cronbach's alpha coefficient was employed to assess the internal consistency. The test-retest reliability was determined by intra-class correlation coefficient (ICC). Pearson's correlation coefficient was detected to evaluate the criterion validity between the SC-LEFS and WOMAC/SF-36/range of motion (ROM). Construct validity was assessed by exploratory factorial analysis. Additionally, responsiveness analysis was conducted with effect size (ES) and standardized response mean (SRM). Results The results revealed good internal consistency (Cronbach's alpha = 0.975) and good test-retest reliability (ICC = 0.937). Strong correlations were observed between the SC-LEFS and WOMAC pain/function/total, physical component summary of SF-36, and ROM. We confirmed the SC-LEFS as a two-factor structure with factor 1 and factor 2 explaining 73.781% and 5.546% of the variance, respectively. The ES (1.74) and SRM (1.95) indicated a good responsiveness. Conclusions The SC-LEFS has been nicely adapted into simplified Chinese. It was proved to be reliable and valid for knee OA patients from China mainland who are undergoing arthroplasty. Furthermore, additional research should be conducted to assess these findings in other dysfunctions of lower extremity in a larger sample size.