Knee replacement surgery is the second most common surgery in Canada. People who have very painful knee arthritis usually receive a knee replacement where the surgeon aims to make everyone's knee as straight as possible (called mechanical alignment). Mechanical alignment focuses on making the implant last as long as possible. However, everybody's knee shape is different and we think that it is important to take individual differences into account. A newer technique that is more personalized is called restricted kinematic alignment. This technique customizes the placement of the new knee to reproduce each patient's unique knee shape, which may not be perfectly straight. We think this newer technique may feel more natural, be more stable, and lead to better knee function. Restricted kinematic alignment might last as long or longer than mechanical alignment, but the research that has been conducted to date is not clear. We are conducting this study to help surgeons better understand which technique is better. One of the reasons the existing research is not clear is because new developments in robotic technology now allow surgeons to place knee implants very precisely, which was not done in most previous research. In this study everyone will receive a robot-assisted knee surgery so we can be sure the implants are placed as precisely as possible. The purpose of this trial is to determine whether there are differences in patient outcomes using restricted kinematic alignment rather than the traditionally used mechanical alignment for total knee replacements. Participants who are having total knee replacements will be randomized to receive either a robot-assisted total knee replacement using mechanical alignment, or a robot-assisted total knee replacement using restricted kinematic alignment . We will ask participants to walk in a markerless motion capture system which will measure walking characteristics at pre-op, 6 months postop and 12 months postop. Participants will also complete a series of standardized questionnaires at preop and 6 months, 12 months, and 24 month postop.