MultiCenter IDE Study of the PEEK-OPTIMA™ Femoral Component vs a CoCr Alloy TKA Femoral Component of Similar Design

Inclusion Criteria: * Male and female subjects 18 years of age or older. * Subjects with a primary diagnosis of end-stage symptomatic unilateral primary knee osteoarthritis. * Subjects with a pre-operative Knee Society Score (KSS) Knee score of \>25 and \<75. * Subjects who, in the opinion of the Investigator, can understand this clinical investigation, co-operate with the investigational procedures and are willing to return to the hospital for all the required post-operative follow-ups. * Subjects who can give voluntary, written informed consent to participate in this clinical investigation and from whom consent has been obtained. Exclusion Criteria: * Subjects who, in the opinion of the Investigator, have an existing condition that would compromise their participation and follow-up in this clinical investigation. * Subjects who are known drug or alcohol abusers or with psychological disorders that could affect follow-up care or treatment outcomes. * Subjects who have participated in a clinical study with an investigational product in the last 6 months. * Subjects with other significant disabling problems from the muscular-skeletal system other than in the knees (i.e.: muscular dystrophy, polio, neuropathic joints). * Subjects with known osteoporosis and/or previous history of fracture related to osteoporosis. * Subjects with a current or active history of malignancy, active or suspected infection, Paget's disease, renal osteodystrophy, immunologically suppressed, rheumat…