The study was terminated early due to a change in business strategy at the sponsor, unrelated to any safety concerns with the medical device.

A prospective, multicenter, randomized, parallel controlled study evaluating the safety and efficacy of Chondro-Gide® bilayer collagen membrane in knee cartilage defect repair. The objective of this clinical trial is to evaluate the efficacy and safety of Chondro-Gide® bilayer collagen membrane in knee cartilage defect repair

This is a prospective, multicenter, randomized, parallel controlled and superiority clinical trial. It is planned to be carried out in hospitals with qualifications as a national-level clinical trial institution. Subjects who have signed the ICF, meet all inclusion criteria and do not meet any exclusion criteria will be included in this study. Subjects included will be randomly assigned into the experimental group and the control group at a ratio of 1:1. Those in the control group will receive microfracture, and those in the experimental group will receive microfracture plus Chondro-Gide® bilayer collagen membrane. The primary efficacy evaluation indicator of this clinical study is the MOCART score at 24 months postoperative. The secondary efficacy evaluation indicators are IKDC score (before operation, 3, 6, 12 and 24 months postoperative), MOCART score (6 and 12 months postoperative), hyaline cartilage production (T2 mapping ratio) (12 and 24 months postoperative), Lysholm score (before operation, 3, 6, 12 and 24 months postoperative), and device performance evaluation of the investigational product. Safety evaluation indicators include adverse events (or serious adverse events), device-related adverse events (or serious adverse events), device deficiencies and laboratory examination.

Inclusion Criteria:

1. Male or female patients aged 18-55 years (including 18 years and 55 years);
2. Localized cartilage defects on knee joint, the size of the defect after debridement is 2.0 squared cm - 8.0 squared cm (including 2.0 squared cm and 8.0 squared cm), which was classified by the International Cartilage Repair Society (ICRS) as grade Ⅲ or grade IV;
3. The subjects voluntarily consent to participate in this trial and sign the informed consent form (ICF).

Exclusion Criteria:

1. Body mass index (BMI) ≥ 30 kg/meter squared (BMI = weight divided by height squared);
2. Unilateral knee cartilage defect with the ICRS classification of grade III or grade IV, and with three or more defects;
3. Patients with abnormal lower limb mechanical axis requiring correction, except those that could be corrected during the treatment of cartilage injury;
4. Varus or valgus of lower limb axis > 5°, requiring osteotomy for correction;
5. Patients with multiple ligament injury or total meniscectomy;
6. Those who are known to be allergic to porcine-derived materials or collagen, or refuse to use porcine-derived medical products;
7. Those with severe arthroclisis or arthrofibrosis;
8. Those who have received open knee surgery in the past 6 months;
9. Those who have received microfracture, mosaicplasty or autologous cartilage implantation in the past 3 months;
10. Those who have serious primary cardiovascular diseases, lung diseases, endocrine and metabolic diseases (severe diabetes, severe osteoporosis) or serious diseases affecting their survival, and are considered unsuitable for inclusion by the investigators;
11. Pregnant and lactating women, or those who plan to conceive during the trial, and those who have positive blood/urine pregnancy test results before the trial;
12. Patients with knee infection；
13. Those with connective tissue diseases;
14. Those with nervous system diseases or muscle degeneration;
15. Patients who participated in drug clinical trials within 3 months prior to the enrollment or patients who participated in any other device clinical trials within 1 months prior to the enrollment;
16. Other circumstances which are considered by the investigator not suitable for enrollment in this study.

The outcome assessors will be blinded, i.e., the outcome assessors will not participate in the operation and do not know the subject grouping information. The outcome assessors will make efficacy judgment based on MRI results, so as to reduce study bias caused by subjective assessment error.