Total knee arthroplasty (TKA) is a prevalent solution for severe knee osteoarthritis, yet the comparative efficacy between posterior stabilized (PS) and bi-cruciate stabilized (BCS) implants remains undefined, as does performance variance in daily activities. In this study, sixty individuals (20 per group in PS-TKA, BCS-TKA, and controls) were recruited and evaluated at pre-op and six-month post-op. Human motion analysis was performed during five daily activities, such as level walking. Knee joint biomechanics, muscle activities, and a newly formulated Knee Biomechanics Index (KBI), along with clinical assessment, were compared among three groups.
Patients exhibited significant functional improvement at post-op, more pronounced in level walking, with stair climbing remaining problematic. Both TKA groups demonstrated comparable performance enhancements and pain relief, albeit with nuanced distinctions in joint range of motion during stair ambulation. Notably, unilateral TKA patients still experienced bilateral discrepancies at six-month post-op, evident in strenuous tasks due to enduring imbalances in knee forces and muscle activities. There were noticeable differences in performance and persistent bilateral differences at post-op between TKA groups. These insights are critical for surgeons in tailoring implant choices and for therapists in optimizing rehabilitation strategies, ensuring focused recovery plans that cater to individual patient needs and activity-specific demands.