Sensitivity and Specificity Analysis of Distance between the Knees for Genu Varum Assessment

Purpose: This study examined the differences and correlations between the Q-angle and inter-knee distance for a genu varum evaluation.The sensitivity and specificity of inter-knee distance were analyzed using ROC curves, and their optimal discriminatory cutoff values were determined.Methods: This study measured the Q-angle and inter-knee distance in 17 individuals with genu varum and 15 healthy controls in their 20s.The measurements were taken using radiographic equipment and digital calipers.Independent t-tests compared the group differences, and Pearson correlation analysis determined the relationship between the two measurements.Furthermore, ROC curve analysis was used to assess the sensitivity, specificity, and discriminatory cutoff points of inter-knee distance for genu varum evaluation.Results: Males and females exhibited smaller Q angles and larger distances between the knees in cases of genu varum.Furthermore, a significant negative correlation was observed between the two evaluation methods.Moreover, the distance between the knees revealed high sensitivity and specificity, with a high AUC value in the ROC curve analysis.Conclusion: These findings show that the distance between the knees can be as useful as the Q angle in evaluating genu varum.These results provide evidence for assessing genu varum using the distance between the knees.