Knee joint cartilage cells metabolize slowly, and it is difficult to repair themselves after injury. Any knee joint trauma or the progression of osteoarthritis may lead to the progression of cartilage or osteochondral defects. Compared with bone marrow mesenchymal stem cells (MSCs), peripheral blood MSCs have better chondrogenic differentiation ability. At the same time, the mobilization of peripheral blood MSCs and the advancement of extraction technology also make it feasible to treat osteochondral damage by using peripheral blood MSCs. The purpose of this study is to evaluate the therapeutic effect of surgical transplantation of autologous peripheral blood MSCs to repair knee joint Ⅳ-degree localized cartilage injury, and to explore a new treatment for osteochondral defects based on the foundation of the research group's previous research.

1. Explore the clinical efficacy of autologous peripheral blood mesenchymal stem cell transplantation in the treatment of osteochondral defects
2. Exploring the characteristics of cartilage regeneration in autologous peripheral blood mesenchymal stem cell transplantation

Inclusion Criteria:

1. Adults over 18 and under 60, regardless of gender.
2. Symptoms, signs and imaging changes are consistent with knee joint limitations IV cartilage defect or patella chondromalacia, patellofemoral joint cartilage injury, mild to moderate knee osteoarthritis.
3. Other treatments are ineffective.
4. No treatment for other knee cartilage defects during the specified period of the test.
5. The subject must be able to communicate well with the researcher and comply with the research requirements, and must give written, signed and dated informed consent before conducting any research-related activities. All relevant legal representatives will also sign a written research agreement in accordance with local laws and regulations.

Exclusion Criteria:

1. The diameter of the cartilage defect in the patient is less than 5mm.
2. Grade Ⅲ and Ⅳ knee joint OA.
3. The patient's symptoms and signs are not closely related to the cartilage defect area.
4. Suffering from concomitant inflammatory diseases (such as rheumatoid arthritis), osteochondrotis dissecans, sepsis, osteonecrosis, and various tumor diseases in the past; in the past three months, there was in the joint cavity of the affected knee History of injection.
5. Suffer from the underlying medical conditions (including but not limited to metabolism, hematology, kidney, liver, lung, nerve , Endocrine, heart, infection, or gastrointestinal tract); currently suffering from a serious progressive or uncontrolled disease that is not suitable for the test or puts it at high risk, including the researchers belief that it will prevent the subject from following the protocol or completing the study according to the protocol Any medical or psychiatric condition of
6. Being infected with human immunodeficiency virus (HIV), infectious hepatitis B or hepatitis C or corresponding medical history.
7. Suffer from a progressive infection or malignant disease, and be able to produce chest X-ray, computed tomography (CT scan) or MRI evidence within 12 weeks before screening, and be evaluated and confirmed by a qualified physician.
8. Active systemic infections (except colds) or any other infections that will recur regularly in the previous two weeks.
9. There is a history of chronic or recurrent infectious diseases, or evidence of tuberculosis infection that was judged to be positive at the time of screening. Subjects who have obtained positive or uncertain results can participate in the study if they undergo a comprehensive tuberculosis examination (according to local practice/guidelines) within 12 weeks before baseline and finally prove that there is no evidence of active tuberculosis. If the presence of latent tuberculosis is confirmed, treatment must be initiated and maintained in accordance with local or national guidelines before the baseline.
10. History of lymphoproliferative disease, or any known malignant tumor, or history of malignant tumor of any organ system in the past 5 years (Bowen's disease, basal cell carcinoma, or actinic keratosis after treatment and no evidence of recurrence in the past 12 weeks Except for diseases; except for excised cervical carcinoma in situ or non-invasive malignant colon polyps).
11. Suffer from medical problems at the same time, including but not limited to the following:
12. Uncontrolled hypertension (systolic blood pressure ≥160mmHg and/or diastolic blood pressure ≥95mmHg), congestive heart failure (New York Heart Association status classification III or IV).
13. Subjects whose serum creatinine level exceeds 2.0 mg/dl (176.8 μmol/L).
14. Total white blood cell (WBC) count at screening <2500/μL, or platelet <100000/μL or neutrophil <1500/μL or hemoglobin <8.5 g/dL.
15. For pregnant or lactating women, pregnancy is defined as the state of a woman after conception until the termination of pregnancy, which is confirmed by the positive result of the hCG laboratory test.
16. Women with childbearing potential are defined as all women who are physiologically able to become pregnant, unless they use effective contraceptive methods during the entire study treatment administration period.
17. In the six months before the baseline, there is a history of alcohol or drug abuse or evidence of ongoing abuse.
18. A history of allergies to the components of the therapeutic drugs used.
19. The returning visitors cannot be tracked in time.