Evaluation of the Agili-C Biphasic Implant in the Knee Joint

Inclusion Criteria 1. 18 to 55 years 2. Symptomatic, single, focal, full or near full-thickness (ICRS cartilage defect description grades 3 and 4) chondral or osteochondral isolated lesion of the femoral condyle, trochlea or the tibial plateau * Defect area is less than 2 cm² after debridement. The defect is completely surrounded on all sides by healthy cartilage. * Osteochondral defect ICRS Cartilage defect description type 1, 2, 3, 4A. Maximal defect depth should be up to 3 millimeters. 3. Primary or secondary articular cartilage repair. 4. Knee is stable or can be stabilized as a concomitant procedure. 5. Must be physically and mentally willing and able to comply with post-operative rehabilitation and routinely schedule clinical and radiographic visits. 6. Signed informed consent. 7. Any misalignments should be fully corrected at the end of the operative procedure. Exclusion Criteria 1. Uncorrected axial misalignments \>5° that cannot be corrected. 2. Patellar cartilage defects or pathology. 3. Meniscal resection of more than 50%, either in a previous procedure or concomitant with articular cartilage repair. 4. Any tumor of the ipsilateral knee, any concurrent malignant tumor or any metastatic tumor in the past or in the present. 5. Active acute or chronic infection of the treated knee. 6. Inflammatory arthropathy or crystal-deposition arthropathy. 7. Systemic cartilage and/or bone disorder; This implants integration is dependent on surrounding live bleeding bone; therefore it must not be implanted within sequestrated or necrotic bone. 8. Bony defect depth over 3 millimeters. 9. Body mass index \>35. 10. Asymptomatic articular cartilage defects. 11. Bipolar articular cartilage defects. 12. Osteoarthritis of the operated knee. 13. Oral medications such as systemic corticosteroid therapy taken less than one year prior to surgery or chemotherapy. * Previous operative treatment of Arthroscopic marrow stimulation technique or cell therapy operated within the last 6 months * Any previous operation of cartilage treatment within the last 6 months 14. Patients who are sensitive to materials containing calcium carbonate or hyaluronate 15. Pregnant women, women who plan to become pregnant and breastfeeding women. 16. Evidence of any significant systemic disease (such as but not limited to HIV infection, hepatitis infection or HTLV infection), known coagulopathies, severe vascular or neurological disease or acute injury that might compromise the patient's welfare. 17. Substance abuse or alcohol abuse. 18. Participation in another clinical trials in parallel to this study. 19. Type I diabetes. 20. Unable to undergo MRI or X-ray. 21. Any reasons making the patient a poor candidate in the opinion of the investigator.