Comprehensive analysis of total knee arthroplasty kinematics and functional recovery: Exploring full-body gait deviations in patients with knee osteoarthritis

Total Knee Arthroplasty has well-established success in relieving knee pain and improving function but patients do not reach functional levels of control groups after surgery and 20% of patients remain unsatisfied. To understand the different patient profiles and develop patient-specific approaches of care, functional phenotypes based on knee biomechanics during gait have been evaluated. To widen the understanding of patient's function, it seems crucial to consider the gait devieations at the whole body level. Thus, this study aims at 1) assessing the impact of knee OA on full-body gait mechanics, 2) assessing whether potential deviations persist one year after TKA surgery, and 3) their potential impact on satisfaction. To that end, clinical gait analysis was performed before and one year after surgery for 100 patients planned for unilateral primary TKA, along with 32 healthy participants as control group. Patients were clustered by applying K-means algorithms on full-body kinematic features of gait before surgery. The knee was excluded from classification to focus on full-body kinematics. Differences between groups, with controls, as well as before and after surgery were evaluated for patients reported outcome measures, kinematic features, and spatio-temporal parameters. Three functional groups were identified. One low-functioning cluster with mostly elderly women showing significant functional improvement one year after surgery, and two high-functioning clusters differentiated by pelvis tilt (anteversion vs. retroversion), sagittal knee alignment (varus vs. neutral), and knee flexion during stance phase (flexum vs. extended) that showed limited improvement one year after surgery. Satisfaction rates were similar among clusters and mental scores improved for all clusters. High functioning patients may benefit from TKA, mostly due to pain reduction, but may not see significant improvement of their function, with no clear impact on satisfaction rate. On the contrary, patients with important functional limitation are more likely to improve both pain and functional outcomes.