DeNovo NT Natural Tissue Graft Stratified Knee Study

INCLUSION CRITERIA: 1. Voluntary signature of the IRB approved Informed Consent, 2. Male or female subjects between the ages of 18 to 55 years, 3. If female: Actively practicing a contraception method and willing to continue for a minimum of 1 year postoperatively, practicing abstinence and willing to continue for a minimum of 1 year postoperatively, or sterile 4. One or two contained lesion(s) of the femur or patella ≥ ICRS Grade 3 or OCD lesions with healed bone base with no loss of bone greater than 6mm 5. Has peripheral cartilage debridement to healthy cartilage that results in at least one lesion with an area of ≥ 2 cm2 and ≤ 7.5 cm2, 6. Lesion(s) to be treated must be contained/shouldered \> 70% of the periphery, 7. Ligaments in the affected knee are stable, 8. Ipsilateral knee compartment has intact menisci 9. The contralateral knee is asymptomatic, stable, and fully functional, 10. Is refractory to conservative non-surgical management or minimal surgical intervention and ≥ 3 months from the start of either treatment, 11. Must record a response, at the preoperative study visit, of moderate to extreme pain for any one of the KOOS Pain Scale questions, P2 through P9. 12. Must be physically and mentally willing and able, in the Investigator's opinion at the time of enrollment, to be compliant with the protocol EXCLUSION CRITERIA: 1. Clinical disease diagnosis of the indexed affected joint that includes * Osteoarthritis or avascular necrosis, * Rheumatoid arthritis, or history of septic or reactive arthritis, * Gout or a history of gout or pseudogout in the affected knee, * Bipolar articular cartilage involvement (or kissing lesions) * Has more than two clinically relevant chondral lesion(s) on the index knee, * Osteochondritis dissecans of the knee with significant bone loss * Associated damage to the underlying subchondral bone requiring bone graft, * Has well-defined subchondral cyst(s), * Has current or impending subchondral avascular necrosis, 2. History of secondary arthropathies (i.e., sickle cell disease, hemochromatosis, or autoimmune disease), 3. Uncontrolled diabetes, 4. Displays a high surgical risk due to unstable cardiac and/or pulmonary disease, 5. Has HIV or other immunodeficient state 6. Is at substantial risk for the need of organ transplantation 7. Is pregnant or breast-feeding, 8. Body Mass Index \>35 (BMI=kg/m2), 9. Is participating concurrently in another clinical trial 10. Is receiving prescription pain medication other than NSAIDs or acetaminophen for conditions unrelated to the index knee condition, chronic use of anticoagulants, or taking corticosteroids, 11. Has a neuromuscular, neurosensory, or musculoskeletal deficiency that limits the ability to perform objective functional assessment of either knee, 12. Active joint infection or history of chronic joint infection at the surgical site, 13. Prior total meniscectomy of either knee, 14. Has severe patellofemoral malalignment/maltracking or patellar instability 15. Radiographically has \>5 degrees of malalignment 16. Has received, within the past 3 months HA or cortisone injections in knee, 17. Has undergone prior tendon repair, meniscus repair, ligament repair or distal realignment/osteotomy surgery in the index knee, \< 6 months prior to surgery, 18. Failed marrow stimulation or ACI treatment performed \< 12-mo before baseline, 19. Index knee has been surgically treated for cartilage repair with OATs, mosaicplasty or osteochondral allograft, 20. Involves concomitant procedures in the affected knee with the exception of incidental loose body removal, debridement, synovectomy, retinacular release, and/or partial meniscectomy 21. Has contraindications for Magnetic Resonance Imaging (MRI), 22. Has an allergy to Polymyxin B sulfate or Bacitracin antibiotics, 23. Is receiving workman's compensation or currently involved in litigation relating to the index knee