Sixty-five patients with bilateral knee osteoarthritis were randomized to undergo simultaneous bilateral total knee arthroplasty with one knee receiving the kinematic alignment (KA) technique and the other the mechanical alignment (MA) technique. The primary outcome of interest was patient-reported functional outcomes, measured by the Forgotten Joint Score (FJS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. Secondary outcomes included surgery duration, recovery time, maximum knee flexion, and radiographic alignment parameters. Outcomes were assessed over a 2-year follow-up. Overall, the results revealed that the KA technique had significantly better WOMAC and FJS scores, shorter surgery duration, faster recovery, and greater knee flexion compared to the MA technique. However, survivorship rates and complications were similar. These findings suggest KA may offer superior short-term outcomes, but both techniques have similar safety profiles.