A Post-Market Retrospective Study on Revision Total Knee Arthroplasty Using Medacta GMK® Revision Prosthesis

Inclusion Criteria: * Patients who are willing and able to provide written informed consent for participation in the study. Written informed consent must be obtained prior to any study procedure. * Patients with ability to understand and provide written authorization for use and disclosure of personal health information * Patients must be willing to comply with the post-operative evaluation schedule. * Patients underwent either a primary or revision total knee replacement for any type of etiology (Osteoarthritis, Avascular necrosis, Rheumatoid Arthritis, Post-traumatic Arthritis, Polyarthritis, Primary implantation failure). * Patients must have received a GMK Revision component * Patients must be at minimum 2 year (24 months) post-treatment * The operation was performed or supervised by the investigator. * No age limit criteria Exclusion Criteria: * History of alcoholism * Currently on chemotherapy or radiation therapy * Habitual use of narcotic pain medications prior to surgery or after surgery for reasons other than knee pain * History of a metabolic disorder affecting the skeletal system other than osteoarthritis or osteoporosis * History of chronic pain issues for reasons other than knee pain * Women that are pregnant