Randomised controlled trial to assess an all-polyethylene tibia medial rotation knee implant compared to a metal-backed tibia implant

INTERVENTION: Participants in the study will all be undergoing total knee arthroplasty, group A will receive the all‐polyethylene tibia medial rotation knee implant whereas group B will receive the metal‐backed tibial medial rotation knee. CONDITION: Patients undergoing total knee arthroplasty for any indication. ; Musculoskeletal Diseases ; Total knee arthroplasty PRIMARY OUTCOME: Compare the mean range of motion (ROM) of the all‐polyethylene tibia MRK to the metal‐backed tibia MRK. A difference of means in ROM of 5 degrees or more will be used to determine if there is a difference in the clinical outcome of the all‐polyethylene tibia and the metal‐backed tibia. SECONDARY OUTCOME: Patient reported outcome measures will be compared for the two treatment arms, including the Oxford Knee Score, the EQ‐5D, Modified Forgotten Joint Score, and the UCLA Activity score. INCLUSION CRITERIA: 1. Primary total knee arthroplasty (for any indication) 2. Informed consent to participate in the study provided by the patient 3. Patients aged over 18 4. Able to understand and respond to Patient‐reported outcome measures (PROMs) for the duration of the study period