This study is designed to assess the 10-year post-surgery implant survivorship of Total Knee Arthroplasty (TKA) procedures performed using the LEGION Medial stabilized insert, which is FDA approved. Implant survivorship is defined as all of the knee-implanted components without a need for a revision. Questionnaires will be used up to 10 years after surgery to find more about the safety and performance of the device.