Fig. 1
Comparison of the joint angle trajectories in the sagittal plane. This figure compares the averaged profiles of joint angles for the cleaned data. The illustrated trajectories are hip (A, D), knee (B, E), and ankle (C, F) joint angles for both healthy individuals and affected leg of patients in different severity grades pre- (A–C) and post-surgery (D–F). As depicted in (A–C), for all three joints, the average trajectories of healthy individuals and patients are separable. In addition, compared to the other joints, hip joint average trajectories provide better discrimination among healthy individuals and patients in different severity grades. Also, the average joint trajectories of patients in grade 3 and grade 4 are very similar, which makes them difficult to separate. Post-surgery, as illustrated in (D–F), still the trajectories of healthy individuals and patients are separable. However, compared to pre-surgery, the post-surgery trajectories of patients are more similar to those of healthy individuals across all three joints.
