Fig. 4

Two regression models showing the association between preoperative and postoperative HKAA. (a) LRM; (b) GAM. The regression coefficients and 95% CIs in the LRM and GAM are shown as red solid lines and red ranges, respectively. Gray circles are raw data. CI confidence interval, HKAA hip–knee–ankle angle, GAM generalized additive model, LRM linear regression model.