The purpose of this study is to evaluate the efficacy and safety of adding CARTISTEM®(allogenic umbilical cord blood-derived stem cell product) on microfracture, a currently standard treatment for OLT, in patients with talar chondral or osteochondral defect.

Inclusion Criteria:

1. Talar chondral/osteochondral lesion confirmed by radiographical exam at screening or diagnosis, an AOFAS score of 75 or below

2. Ankle joint pain/stiffness with no response to conservative treatment for more than 12 weeks

3. Ankle joint cartilage injury of defect of ICRS grade Ⅳ in MRI

4. Male or female aged more than 18

5. A one-sided lesion

6. Appropriate function of blood clot: PT(INR) < 1.5×ULN, aPTT <1.5×ULN

7. Appropriate renal function: Creatinine ≤ 2.0 ㎎/㎗, Proteinuria ≤ trace

8. Appropriate hepatic function: Total bilirubin ≤ 2.0 ㎎/㎗, AST/ALT ≤ 100 IU/L

9. No evidence of auto-immune disorder: According to investigator's judgement based on relevent symtom and physical exam, anti-nuclear antibody and anti-thyroglobulin antibody tests are able to performed and confirmed negative (If positive, there are possible cases according to diagnostic opinion of medical department)

10. No surgery or radiotherapy for the same ankle joint within 6 weeks

11. Female patients agreeing with maintenance of contraception* during study period

    *hormone contraceptive, implants of intrauterine device or intrauterine system, double barrier contraception[Concurrent use of diaphragm or cervical occlusive cap and male condom], surgical sterilisation, etc.

12. No chronic ligament instability more than grade Ⅲ (Grade 0: none, Grade Ⅰ: 1~5㎜, GradeⅡ: 5~10㎜, Grade Ⅲ: >10㎜)

13. Patients agreeing with participation in this study and signed on informed consent by their own will

Exclusion Criteria:

1. Degenerative arthritis in ankle(Kellgren Lawrence Grade 3-4)

2. Autoimmune disease

3. Infectious disease need to administration of parenteral antibiotics

4. Myocardial infarction, congestive heart failure, other serious cardiac disorder or uncontrolled resistant hypertension

5. Serious medical disease(Ex. Kidney disease such as chronic renal failure or Glomerulonephritis, etc., acute/chronic liver disease such as liver cirrhosis, fatty liver etc., medical history of malignancy*)

   *Complete remission status is possible.

6. Pregnancy or breast-feeding

7. Psychiatric history or epilepsy

8. Alcohol abuse

9. Heavy smoker

10. Chronic inflammatory disease such as rheumatoid arthritis

11. Participants other clinical trials within 4 weeks

12. Administration of immunosuppressing agents such as Cyclosporin A or azathioprine within 6 weeks

13. Patients with acute ligament injury and clinically significant chronic ligament instability

14. Patients treated with surgery or cell therapy product for the same disease

15. Patients with hypersensitivity or allergy history to bovine protein, hyaluronic acid and gentamicin

16. Other inappropriate patients determined by the principal investigator

IPD will not be shared to other researchers.