ATTUNE Revision System in the Revision Total Knee Arthroplasty Population

Inclusion Criteria 1. Subject is male or female and between the ages of 22 and 80 years at the time of consent, inclusive. 2. Subject presents with a primary knee arthroplasty (primary TKA, unicompartmental) or prior revision TKA that requires a revision procedure of implanted tibial and/or femoral components. 3. The decision to perform a knee revision with the study device is regardless of the research. 4. Subject that is willing to give voluntary, written informed consent to participate in this clinical investigation and authorize the transfer of his/her information to the Sponsor 5. Subject is currently not bedridden 6. The devices are to be used according to the approved indications.Subject is able to read, and comprehend the Informed Consent Document as well as complete the required PROMs in either English or one of the available translations. Exclusion Criteria: 1. The Subject is a woman who is pregnant or lactating. 2. Contralateral knee has already been enrolled in this study. 3. Subject had a contralateral amputation. 4. Subject is currently diagnosed with radicular pain from the spine that radiates into the limb to receive RTKA. 5. Subject has participated in a clinical investigation with an investigational product (drug or device) in the last three (3) months. 6. Subject is currently involved in any personal injury litigation, medical-legal or worker's compensation claims. 7. Subject, in the opinion of the Investigator, is a drug or alcohol abuser (in the last 5 years) or has a psychological disorder that could affect his/her ability to complete patient reported questionnaires or be compliant with follow-up requirements. 8. Subject was diagnosed and is taking prescription medications to treat a muscular disorder that limits mobility due to severe stiffness and pain such as fibromyalgia or polymyalgia. 9. Subject has a significant neurological or musculoskeletal disorder(s) or disease that may adversely affect gait or weight bearing activities (e.g., muscular dystrophy, multiple sclerosis, Charcot disease). 10. Subject has a medical condition with less than five (5) years life expectancy as determined by the Investigator. 11. Uncontrolled gout