Evaluation of the 5C® MEDic Knee System

Inclusion Criteria: 1. Voluntary written informed consent of the participant has been obtained prior to any screening procedures 2. At least 18 years of age at the time of signing the Informed Consent Form (ICF) 3. The patient will be operated at the Leuven University Hospital (primary or revision surgery). 4. The patient will receive the 5C® MEDic Knee System (manufactured by implantcast GmbH). 5. The implantation will be performed according to the medical indications listed in the product specific Instruction for Use (IFU): 1. Non-inflammatory degenerative joint disease including osteoarthritis and avascular necrosis, 2. Post-traumatic osteoarthritis 3. Treatment of fractures that are unmanageable using other surgical techniques 4. Rheumatoid arthritis 5. Revision arthroplasty (revision prosthesis) 6. The patient is willing and able to follow all study specific procedures and to attend the follow-up visits at the study site 7. The patient agrees to be contacted by telephone or by mail. Exclusion Criteria: 1. The patient is \<18 years of age, or unable to understand and sign a written informed consent form or legally incompetent or limited in his legal capacity. 2. Patient has history of malignancy within the past 5 years before screening. 3. Patients with Adipositas permagna (BMI ≥40 kg/m²). 4. Has a current infection as well as infections close (in the opinion of the investigator) to the knee joint within the last 3 years. 5. Known allergy to any of the implant materials. 6. Female who is pregnant or intends to become pregnant during screening and at the moment of operation 7. Not a suitable candidate for enrollment or unlikely to comply with the requirements of this study, as assessed by the Investigator. 8. Current alcohol and/or drug abuse or other addictions that might impair the patient's capacity to estimate the nature and the scope of the study. 9. Bilateral Total Knee Arthroplasty in a period of \< 3 months. 10. Physiological or anatomical conditions, which preclude or are not expected to maintain adequate bony support of the implant or do not allow the implantation of a sufficiently large prosthesis, in the opinion of the investigator. 11. Bone tumors in the implant fixation area. 12. Has an untreated vascular diseases which limit blood supply to the affected limb, in the opinion of the investigator 13. Has a metabolic disorders that may impair bone formation. 14. In case of insufficient quantity and quality of bone stock, an alternative prosthetic treatment allowing for sufficient bony fixation should be considered. 15. Has severe axis deviation in treated knee under study and/or non-treated knee. 16. Ligament instability in treated knee under study. 17. Participation in an interventional trial with an investigational medicinal product (IMP) or device within the last four weeks before Screening. 18. Any other clinical history finding that, in the judgment of the investigator, would pose a potential hazard for performing a knee surgery