Survivorship of Attune Primary Total Knee Prosthesis

Approximately 30 sites, worldwide, will recruit 1200 patients (1200 knees). Each study site is expected to enroll approximately 50 patients (50 knees). An additional 10 subjects per site may be recruited at sites which have Sub-Investigators participating in the study. Cohort reallocation is permitted. There is no control group. One thousand two hundred (1200) Subjects will be stratified into 4 subgroups of 300: cruciate retaining fixed bearing(CR FB), cruciate retaining rotating platform (CR RP), posterior stabilized fixed bearing (PS FB), and posterior stabilized rotating platform (PS RP). Treatment assignment in this study is not randomized. Each site will only enroll patients in one of the four knee configuration sub-groups most commonly used as their standard of care. This study allowed for enrolment into the study by two methods. The first method was by enroling subjects to receive the implant under study with the expectation to follow them out to 15 years. The second method was done to offset follow-up attrition. The second method allowed additional interested sites that had previously participated in a two-year follow-up study (NCT01746524) on this implant (subjects implanted and followed for two years) to reconsent interested subjects to be further followed out to 15 years in this study. The original 29 sites enroled 1232 subjects. Adding of the interested sites from the 2-yr follow-up study (NCT01746524) increased the sites from 29 to 37 sites. As of the last study update, the current enrolment is now1538.