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, rheumatoid arthritis, sickle cell anemia, and systemic lupus erythematosus. * Subjects defined by the Investigator as American Society of Anesthesiologists (ASA) Grade III or IV. * Subjects who have a neuromuscular or neurosensory deficit. * Female subjects who are pregnant or lactating. * Subjects with an anatomical limb alignment of above 20 degrees varus or valgus. * Subjects with primary or secondary diagnosis of inflammatory or traumatic arthritis. * Subjects with a fixed flexion deformity of over 20 degrees. * Subjects with recurvatum (definition: hyperextension ≥ 5 degrees). * Subjects who have previously undergone surgery on the indicated knee including total knee arthroplasty, patellofemoral arthroplasty, or unicondylar knee arthroplasty, high tibial osteotomy, ligament reconstruction, fusion, open reduction and internal fixation. * Subjects that have undergone, or scheduled to undergo, contralateral total knee arthroplasty or unicondylar knee arthroplasty within ±1 year from the study surgical procedure. * Evidence of active or suspected (systemic or local) infection at time of surgery.