Study Summary

Sixty patients with knee osteoarthritis were randomized to receive either functional alignment (FA) (n=29) or adjusted mechanical alignment (aMA) (n=31) using a robotically assisted cruciate-retaining total knee arthroplasty. The primary outcome was the intraoperative kinematic pattern (medial pivot, symmetrical rollback, or lateral pivot) assessed with a pressure sensor after definitive implantation. Secondary outcomes included knee balance, range of motion, and multiple patient-reported outcome measures (PROMs) at 12 months. FA produced a medial pivot in 58.6%, symmetrical rollback in 37.9%, and lateral pivot in 3.4% of cases; aMA produced a medial pivot in 19.4%, symmetrical rollback in 45.2%, and lateral pivot in 35.5%. Medial pivot patterns were associated with higher Forgotten Joint Scores, EQ-5D VAS, and lower rest pain, whereas lateral pivot patterns were linked to lower Kujala scores. Overall, FA more consistently replicated native medial pivot kinematics, which correlated with better clinical outcomes compared to lateral pivot patterns. These findings suggest alignment strategy influences intraoperative kinematics and may impact functional recovery.