MicroPort (MPO) is conducting this PMCF study to evaluate the safety and effectiveness of its EVOLUTION® Revision Tibial System and EVOLUTION® Revision STEMMED CS Femur with the EVOLUTION® MP CS Tibial Insert. This type of study is required by regulatory authorities for all devices that have been approved in Europe to evaluate the medium and long-term clinical evidence.

The primary objective of this study is to estimate individual component survivorship for tibial base, femoral component, and tibial insert at specified intervals out to 10 years follow-up.

The secondary objectives include:

• Determine the cumulative incidence of individual component revision at specified intervals out to 10 years follow-up;
• Characterize functional scores for subjects, as assessed by KOOS Scores and EQ-5D-5L Scores, out to 10 years follow-up;
• To assess subject satisfaction with their TKA procedure using the Forgotten Joint Score and a Satisfaction Survey;
• To assess the presence, zone, and the size of radiolucencies surrounding implanted components out to 10 years follow-up;
• To assess safety and characterize protocol defined adverse events and adverse device effects.

Inclusion Criteria:

1. Has previously undergone or currently has been determined to undergo a revision knee arthroplasty that requires implantation of the components under study (EVOLUTION® Revision Tibial System and EVOLUTION® STEMMED CS Femur with the EVOLUTION® MP CS Tibial Insert)
2. Decision to perform the study index surgery with the required study components is pre-determined regardless of the research;
3. Previously implanted subjects must be enrolled within 3 years (+ 6 months) of their study index surgery
4. Willing to voluntarily sign the informed consent form
5. Willing and able to comply with the protocol, able to read and complete the required forms, and willing and able to adhere to the requirements of the protocol through the 10-year postoperative follow-up visit.

Exclusion Criteria:

1. Skeletally immature (less than 21 years of age) at time of implantation
2. Has or had an overt infection at the time of implantation
3. Has or had inadequate neuromuscular status (e.g., prior paralysis, fusion, and/or inadequate abductor strength), poor bone stock, poor skin coverage around the joint which would make the procedure unjustifiable
4. Currently enrolled in another clinical investigation which could affect the endpoints of this protocol
5. Has or had documented substance abuse issues
6. Has or had an emotional or neurological condition that would pre-empt their ability or willingness to participate in the study
7. Currently incarcerated or has impending incarceration
8. Has a medical condition, as judged by the Investigator, that would interfere with the subject's ability to comply with the requirements of the protocol

Multicenter, prospective follow-up study of newly or previously implanted subjects. Previously implanted subjects must be enrolled within 3 years (+ 6 months) of the study index surgery.