A Study on Kinematic Differences Between Leading and Trailing Legs During Obstacle-Crossing Pre- and Post-Total Knee Arthroplasty

This study aims to clarify the kinematic and kinetic differences between the leading and trailing legs during obstacle-crossing in order to support safer post-TKA living.

The study included seven patients scheduled for total knee arthroplasty (TKA), who were able to walk independently for at least 10 meters and were diagnosed with grade 3 or 4 osteoarthritis according to the Kellgren-Lawrence classification (KL classification). Measurements were taken preoperatively and at five weeks postoperatively. The target motion was an obstacle-crossing task starting from a standing position, where the patient crossed an obstacle placed in front of them. Motion analysis was conducted using six infrared cameras and the VICON MX system, and kinematic data were calculated using the Plug-in-Gait model. The obstacle heights were set at 0%, 5%, and 10% of the patient’s height, with the starting position located 10% of their height in front of the obstacle. The analysis focused on the swing leg's hip, knee, ankle, thorax, pelvis angles, and toe clearance when the leading and trailing legs were directly above the obstacle. Additionally, comparisons were made between the same leg (either leading or trailing) during obstacle-crossing at different obstacle heights (0%, 5%, and 10%) before and after TKA, with a significance level set at 5%.

When stepping over from the affected side postoperatively, hip abduction angle significantly decreased when crossing obstacles at 5% and 10% heights, and knee flexion angle significantly decreased at 10% height. For the trailing leg, forward thorax inclination angle significantly decreased at the 5% height. When stepping over from the unaffected side, lateral thorax tilt toward the stance leg significantly increased postoperatively when crossing at the 5% height.

This study suggests that movement strategies differ before and after TKA during obstacle-crossing tasks. These changes in movement strategies indicate key areas that should be emphasized in postoperative rehabilitation.

The results of this study reveal kinematic differences between the leading and trailing legs, providing insights into obstacle-crossing movements. This knowledge may contribute to the improvement of rehabilitation programs for patients following TKA.