A clinical trial to evaluate the long-term efficacy and safety of a CHONDRON (Autologous cultured Chondrocyte) for 48weeks, and additional 96weeks in patients with cartilage defects in their knees.

This is an open trial, involving a total of 24 subjects. Subjects who give consent will be screened and those who meet trial criteria will receive CHONDRON (Autologous cultured Chondrocyte) by transplant. During the trial period, subjects must follow the instructions given by principal investigator. Subjects will make 8* hospital visits on a regular basis inclusive of hospitalization. During these visits subjects will be examined. For the evaluation of safety and efficacy of CHONDRON, examination with doctors, blood samples, x-ray, MRI tests, observation with the naked eyes and arthroscopy will be performed. *If tissue samples can be collected at screening visit, there will be only 7 visits.

Inclusion Criteria:

1. Patients with cartilage defects in their knee (Including Knee OA and Knee TA) * For a single lesion, less than 15 cm2 cartilage defects; and for multiple lesions, less than 20 cm2
2. Patients with misalignment of their tibia and femur, unstable ligament in their knee, or bony defects in the lesions of their knee, and/or who had been treated for alignment
3. Patients which surrounding cartilage are normal
4. Patients who were 15 years old or older
5. Patients or their representative (for adults), or patients and their parent/guardian (for minors), who agreed to participate in the study and signed the informed consent form

Exclusion Criteria:

1. Patients hypersensitive to bovine protein
2. Patients hypersensitive to gentamicin antibiotics
3. Patients with inflammatory arthritis such as rheumatoid arthritis, gout arthritis
4. Patients with arthritis related to autoimmune disease
5. Pregnant, breast-feeding patients or those who have a possibility of pregnancy
6. Patients with accompanying diseases other than articular cartilage defects, including tumors (Exception: if the possibility of Chondron treatment is confirmed with doctor's clinical decision).
7. Patients who have a history of receiving radiotherapy, chemotherapy in the last 2 years (Exception: if the possibility of Chondron treatment is confirmed with doctor's clinical decision).
8. Patients with diabetes (however, patients whose blood sugar test results are normal and do not have any complication of diabetes, when a written opinion that CHONDRON administration is possible is appended by a doctor are excluded)
9. Patients with an infection that required hospitalization for antibiotics or the administration of antiseptic agents
10. Patients under adrenocorticoid therapy (Exception: if the possibility of Chondron treatment is confirmed with doctor's clinical decision).
11. Patients with psychiatric disorder and those who are considered to be inappropriate for this trial by the judgment of the clinical trial manager
12. Patients with cartilage defects in both knees (If the necessity of other surgery on the opposite side of knee joint using Chondron is confirmed with doctor's clinical decision).
13. Patients with liver, heart, or kidney disease (Those who show normal or insignificant test results may be enrolled in this study and receive the Chondron based on the investigator's judgment. Hypertension patients are allowed.)
14. Patients who had been infected with a virus (Those who show normal or insignificant test results may be enrolled in this study and receive the Chondron based on the investigator's judgment.)
15. Patients who had participated in another clinical trial (limited to those who participated in other studies on fracture within the last six months.)