<qa>  What is the primary objective of this study?The primary objective of this study is to examine the change from pre-operative baseline to two year postoperative functional performance improvement for the ATTUNE primary, cementless TKA RP system as measured with the KOOS questionnaire KOOS-ADL sub-score. This will be carried out for two configurations: cruciate retaining rotating platform ATTUNE Cementless CR RP and posterior stabilized rotating platform ATTUNE Cementless PS RP. 