Prospective Functional, Gait, and Outcome Comparison Study of Medial Pivot Versus Single Radius Design for Total Knee Arthroplasty

Inclusion Criteria: * Subject is male or non-pregnant female aged between 18 and 75 years of age. * Subject is willing to provide informed consent to participate in the research study. * Subject is indicated for a primary total knee arthroplasty (TKA) based on the approved labeling of knee implant, either a medial pivot or single radius design, specifically: MicroPort Evolution Medial-Pivot Knee System, Cruciate Retaining (CS) or Stryker Triathlon Tritanium (CS) * Subject does not have a history of previous prosthetic replacement device on the operative knee. * Subject is currently ambulating and does not have a condition on the contralateral limb in the opinion of the investigator that would interfere with the gait laboratory evaluations. * Subject is willing and able to comply with the schedule of events for the study and is available to return to the clinic for all required follow-up visits. Exclusion Criteria: * Subject has a Body Mass Index (BMI) \>40 * Subject has a diagnosis of avascular necrosis or inflammatory arthritis. * Subject has any mental or neuromuscular disorder that would create an unacceptable risk of prosthesis instability, prosthesis fixation failure, or complications in postoperative care. * Subject is a prisoner * Subject has any condition, in the opinion of the Investigator that might interfere with the evaluation of the study objectives.