LEGION™ Revision Metal Hypersensitivity Study

Inclusion Criteria: * Subject is skeletally mature * Subject is willing to sign and date an IRB/EC approved consent form * Subject is a candidate for a revision knee replacement * Subject has met an acceptable preoperative medical clearance and is free or treated for cardiac, pulmonary, hematological, infection, or other conditions that would pose excessive operative risk * Subject agrees to adhere to the 10-year study visit schedule Exclusion Criteria: * Subject with a known metal hypersensitivity * Subject requires a known bilateral revision TKA * Subject has severe pronation of the ipsilateral foot or any other relevant clinical condition contributing to abnormal ambulation * Subject has active infection or sepsis (treated or untreated) * Subject with an immunosuppressive disorder * Subject has presence of malignant tumor, metastatic, or neoplastic disease * Subject has conditions that may interfere with the TKA survival or outcome (i.e., Paget's or Charcot's disease, vascular insufficiency, muscular atrophy, uncontrolled diabetes, moderate to severe renal insufficiency or neuromuscular disease) * Subject has had intra-articular corticosteroid therapy (or any other intra-articular therapy) in the study knee within 3 months of study enrollment * Subject has inadequate bone stock to support the device and would require significant augmentation to correct the joint Female subject is of child-bearing age and unwilling to use an approved method of contraception * Subject has an emotional or neurological condition that would pre-empt their ability or willingness to comply with the study * Subject is severely overweight (BMI\>40) * Subject is currently enrolled in another investigational drug, biologic, or device study or has been treated with an investigational product in the past 30 days * Subject is facing current or impending incarceration