Manual Arthroplasty Versus VELYS Robotic-Assisted Solution Functional Alignment Arthroplasty for Knee Osteoarthritis

The goal of this clinical trial is to learn if the VELYS Robotic-Assisted Solution (VRAS) device helps to improve outcomes from total knee replacement, when compared to regular non-robotic-assisted total knee replacement in the treatment of osteoarthritis. It will also aim to review the longer-term safety and efficiency effects of using this device. The main questions it aims to answer are: 1. Does VRAS device-assisted total knee replacement improve patient outcomes (such as their function, satisfaction, and pain) when compared to non-robotic-assisted total knee replacement? 2. Does VRAS device-assisted total knee replacement improve clinical outcomes (such as revision risk, complications, and hospital length of stay) when compared to non-robotic-assisted total knee replacement? 3. Does VRAS device-assisted total knee replacement improve functional outcomes (including biomechanical motion analysis) when compared to non-robotic-assisted total knee replacement? 4. What are the economic and efficiency effects of VRAS device-assisted total knee replacement compared to non-robotic-assisted total knee replacement? 5. What are the human factor and learning curve effects of introducing VRAS device-assisted total knee replacement into healthcare teams? 6. Are there any differences in safety and adverse event incidence between VRAS device-assisted total knee replacement and non-robotic-assisted total knee replacement? Participants will: * Be randomised to receive a total knee replacement using either regular non-robotic-assisted methods, or with the use of the VRAS device. * Be assessed pre-operatively at the clinic, and then at 6 weeks, 6 months, and 12 months following date of operation. At these appointments patients will answer questionnaires, receive an x-ray (pre-operatively, and at 6 months post-operatively), and a subgroup will be reviewed in the motion analysis laboratory (pre-operatively, and at 6 months post-operatively). * Have their longer-term outcomes including any revision operations monitored out to 10 years through national registry data linkage (no actual follow-up for patients after 12 months).