 This study is therefore a post-market study to evaluate the short-, mid- and long-term safety and effectiveness of the LEGIONTM Primary TKS with VERILASTTM bearing surface the combination of an OXINIUMTM femoral component with highly cross-linked polyethylene tibial base plate inserts. The clinical outcome from a large cohort of subjects who are treated with the LEGIONTM Primary TKS as part of their standard of care will be documented. The study is designed to reflect standard clinical practice as closely as possible because it allows the results of such a study to represent the true clinical outcome that would be achieved in clinical practice, up to a maximum. Only subjects who will be treated with the LEGIONTM Primary TKS as part of their normally planned care will screened for participation in this study. 