This study was designed to evaluate the efficacy and safety of a modified microfracture using collagen, and to compare them with those of a simple microfracture in patients with cartilage defects in their ankles.

This study was an open-trial study. Sixty subjects participated in it. The study was explained to the subjects and they voluntarily agreed to participate in it. Their eligibility to participate in the study was checked, and they were randomized either into the simple microfracture group or the modified microfracture group using collagen based on a randomization table. They were asked to follow the guidelines of the investigators during the study and to visit the hospital five times, including for screening. At each visit, the subjects underwent an examination with doctors and MRI to evaluate the efficacy of the procedure. (*If the subject began the first visit on the screening date, the total number of his or her visits was four.)

Inclusion Criteria:

1. Patients who were 15 years old or older
2. Patients with cartilage defects in their ankle
3. Patients with misalignment of their tibia and talus, unstable ligament in their ankle, or bony defects in the lesions of their ankle, and/or who had been treated for alignment
4. 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. If patients or their families suffer from or have ever suffered from an autoimmune disease.
2. Patients who have ever suffered an anaphylactic reaction.
3. Patients who have ever suffered hypersensitivity to an implant.
4. Patients with a history of allergy to porcine or bovine protein.
5. Subjects with inflammatory arthritis, such as rheumatoid and gouty arthritis.
6. Subjects with autoimmune disease related arthritis.
7. Subjects who are pregnant and/or breast-feeding and/or plan a pregnancy.
8. Subjects with tumors.
9. Subjects who have undergone radiotherapy or chemotherapy within the last 2 years (Exception: if the possibility of collagen treatment is confirmed with doctor's clinical decision).
10. Subjects who are diabetic. (Exception: if the possibility of CartiFill™ treatment is confirmed with doctor's clinical decision, and/or patient's blood glucose level remains within the normal range and/or no other complications by diabetes mellitus.)
11. Subjects with infections, currently on treatment with antibiotics or antimicrobials (Exception: if the possibility of collagen treatment is confirmed with doctor's clinical decision).
12. Subjects under adrenocorticoid therapy (Exception: if the possibility of collagen treatment is confirmed with doctor's clinical decision).
13. Subjects with psychiatric disorders who are considered inappropriate to participate in this trial by the Principal Investigator.
14. Patients who have ever suffered contraindications of the used Fibrin sealant. (The major contraindications are as follows: patients with hypersensitivity to aprotinin and those treatments for severe brisk arterial or venous bleeding.)