Clinical Study of Decalcification Bone Scaffold for Cartilage Lesions of the Knee

Inclusion Criteria: * 18-50 years old, male or female * Cartilage defect 2-8 cm² * Subjects have the surgical indication of microfracture and no contradiction * Subjects participate the clinical trial voluntarily, and sign informed consent * Subjects could comply with follow-up Exclusion Criteria: * Participated in other drug or medical device clinical trials in the last 6 months. * Can not accept allogeneic decalcified bone due to religion, ethnic and other issues. * Defect area 2 cm² or 8 cm² or lack of normal cartilage tissue around defect zone. * Complex multi-ligament injury * Suffered from systemic immune disease or systemic, locally infected * Joint fibrosis, joint rigidity, mobility was significantly limited * Moderate and severe osteoarthritis * With contraindications to MRI * Hemophilia * General condition can not tolerate surgery * Pregnant or planned pregnant women and lactating women * With abnormal spirit and selfless ability * Other circumstances judged by doctors that can not participate in the trial