*2.1. Ethical Approval*

This study was an open-label, controlled, randomized, single-center, phase I clinical trial to evaluate the clinical safety of Kartigen® and its clinical improvements versus microfracture. This study was approved by the Taiwan Food and Drug Administration (TFDA, study number 1076026300) and by the Institutional Review Board of Taiwan Adventist Hospital (IRB number: 105-B-09). According to the guidelines of the Declaration of Helsinki, informed consent was obtained from each subject.
