The objective of this study is to accurately assess and compare migration, clinical and radiological outcome and patient reported outcomes of two TKR prostheses: the Cemented ATTUNE™ Fixed Bearing Cruciate Retaining Knee System and the Cemented PFC Sigma Fixed Bearing Cruciate Retaining Knee System, both by DePuy Synthes, Warsaw, Indiana, USA. The primary objective of this study is to compare the magnitude and pattern of migration of the prostheses (Femoral and Tibial component). The secondary objective of this study is to compare clinical and radiological outcome of the prostheses and PROMS. The tertiary objective of this study is to compare clinical and radiological outcome and PROMS of the prostheses with migration data.