This is a long term follow-up study to investigate the safety and efficacy of CARTISTEM®, human umbilical cord blood-derived mesenchymal stem cells, in repair of cartilage injury or defects, compared with microfracture. Subjects who participated in and completed the Phase III trial (NCT01041001) will be tracked until the 60 month post-treatment timepoint.

This long term follow-up study is performed to assess the long-term safety and efficacy of CARTISTEM®, human umbilical cord blood-derived mesenchymal stem cells, in repair of cartilage injury or defects, compared with microfracture. Subjects, who were either administered CARTISTEM or treated with conventional microfracture in the primary phase III study (NCT01041001), will be further observed using various subjective knee assessments and MRI T2 mapping until the 60 month post-treatment timepoint.

Inclusion Criteria:

• Patients with knee joint cartilage defect or injury of ICRS (International Cartilage Repair Society) Grade 4 confirmed by arthroscopy (At screening, patients diagnosed as such with an MRI may be included)
• Male or female patients at least 18 years of age
• Patients whose lesion (unilateral joint) is 2 ㎠ ~ 9㎠ in size
• Patients with articular swelling, tenderness and active range of motion of Grade 2 or below
• Patients with pain in affected joint of 60-mm or below on a 100-mm VAS (visual analogue scale)
• Patients with adequate blood coagulation activity: PT(INR) < 1.5, APTT <1.5×control
• Patients with adequate renal function: Creatinine ≤ 2.0 ㎎/㎗, levels of proteinuria measured with Dipstick: trace or less
• Patients with adequate hepatic function: Bilirubin ≤ 2.0 ㎎/㎗, AST/ALT ≤ 100 IU/L
• Patients who have received no surgery or radiation therapy in the affected joint within the past 6 six weeks, and have recovered from the side effects of such past treatments
• Female patients of childbearing potential must agree to practice adequate methods of birth control to prevent pregnancy during the study
• Patients whose physical examination results show no ligament instability of Grade II or above (Grade 0: none, Grade I: 0-5 mm, Grade II: 5-10 mm, Grade III: >10 mm)
• Patients who voluntarily agreed to enroll in the study and signed an informed consent form

Exclusion Criteria:

• Patients with autoimmune disease or the medical history
• Patients with infections requiring parenteral administration of antibiotics
• Patients with myocardial infarction, ischemic heart failure, other serious heart conditions or uncontrolled hypertension, or any medical history of such diseases
• Patients with serious internal diseases
• Patients who are currently pregnant or nursing
• Patients with psychotic diseases, epilepsy, or any history of such diseases
• Patients with alcohol abuse
• Patients who smoke excessively
• Patients with chronic inflammatory articular diseases such as rheumatoid arthritis
• Patients who were enrolled in any other clinical trials within the past four weeks
• Patients who had been administered with immunosuppressants such as Cyclosporin A or azathioprine within the past six weeks
• Patients whose physical examination results show ligament instability of Grade II or above (Grade 0: none, Grade I: 0-5 mm, Grade II: 5-10 mm, Grade III: >10 mm)
• Patients with a known history of hypersensitivity/allergy to gentamicin
• Patients whom the principal investigator considers inappropriate for the clinical trial due to any other reasons than those listed above