Validity and Reliability of the Thai Versions of the Lysholm Knee Scoring Scale and Tegner Activity Scale

Background: Functional or quality of life questionnaires are important tools in clinical investigations. The Lysholm Knee Scoring Scale and Tegner Activity Scale are knee-specific questionnaires that are widely used to assess knee function. Purpose: To translate both questionnaires into Thai and to assess the validity and reliability of the Thai versions of the Lysholm and adjusted Tegner scales. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: The Lysholm and Tegner scales were translated into Thai by using the forward-backward translation protocol. Because cultural modifications were made to the sports used to measure activity on the Tegner scale, the authors of this study refer to the Thai version as the “Thai adjusted Tegner scale.” The reliability and validity of the translated scales were evaluated by obtaining the responses of 60 consecutive patients (mean age, 40.5 years; 34 male, 26 female); the patients also completed the Thai version of the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF). Criterion validity was tested by correlating the scores from both translated questionnaires with those from the Thai IKDC-SKF, while reliability was assessed by measuring test-retest reliability and internal consistency. Results: The Thai Lysholm scale showed a strong correlation with the Thai IKDC-SKF ( r = 0.89), while the Thai adjusted Tegner scale showed a moderate correlation with the Thai IKDC-SKF ( r = 0.60). The intrarater and test-retest reliability measures were excellent for the Thai Lysholm (intraclass correlation coefficient [ICC], 0.94 and 0.98, respectively) and moderate to good for the Thai adjusted Tegner (ICC, 0.73 and 0.86, respectively). The internal consistency for the Thai Lysholm was acceptable at all the time points (Cronbach alpha, 0.71-0.73). Conclusion: The Thai Lysholm and Thai adjusted Tegner scales adequately retained the characteristics of the original versions. They can be considered reliable instruments for Thai patients with knee-related problems.