Current practice in orthopedics is to recommend TKA implantation with the femoral and tibial components perpendicular to their mechanical axis. Therefore, current surgical technique does not replicate natural knee anatomy and biomechanics. An alternative alignment method that attempts to replicate the kinematics of the knee is " kinematic alignment ". The principle behind kinematic alignment is placement of the TKA components so that the orthogonal 3-D orientation of the 3 axes that describe normal knee kinematics is restored to that of the prearthritic knee. Theoretical benefits of kinematic alignment include less ligamentous release to balance the knee intra-operatively, more rapid recovery, better range of motion (ROM), less post-operative pain, better knee biomechanics, and improved patient satisfaction. However, a major concern is that there are no mid- or long-term data on implant survivorship (absence of loosening) in TKA based on "anatomical" implantation. The investigators propose to compare the clinical results of TKA implanted with mechanical alignment (standard practice) to kinematic alignment, in a double-blind, randomized trial.