The purpose of this study is verify the efficacy and safety of Human Umbilical Cord Mesenchymal Stem Cells (UC-MSC) therapy for patients with Osteoarthritis, and in addition, provide basis for exploring the treatment regimen of UC-MSC therapy in different degree of cartilage defect disease

This is a random, open label, and parallel controled experiment. All patients are selected and sign consent forms, then divided into 3 groups. Doctors collect the basic information of patient. All patients receive laboratory and image examination as baseline. Then, they will give cell treatment based on the clinical protocol. Doctors have follow-up visit on 2 weeks, 1, 2, 3, 6, and 12 months after treatment, and do safety and efficacy evaluation.

Safety evaluation. Researcher collect all examination data of patients and compare with each groups. The safety tests including blood routine, urine routine, hepatorenal function, C reactive protein, erythrocyte sedimentation rate, and tumor marker, etc.

Efficacy evaluation. Based on Lysholm, the international knee documentation committee (IKDC) knee evaluation form, and Visual Analogue Scale/Score (VAS) to examine the change/improvement of knee joint function. By Magnetic Resonance Imaging (MRI) examination, grade patients with Kellgren-Lawrence Grading Scale, Assessment of Preoperative Cartilage Defect Severity (AMADEUS), and observe the change/improvement of patient.

Inclusion Criteria:

• Diagnosis of Knee Osteoarthritis by Kellgren and Lawrence Grading Scale, classified with Grade 2-3
• Confirm with cartilage injury,articular cartilage part or full-thickness injury, by MR (Magnetic Resonance)
• Age <70, no serious organ dysfunction
• Over 2 years knee pain or no very effective with conservative treatments
• Knee pain of VAS (visual analog scale score) is 4 or higher
• Normal hepatic and renal function, no history of gout, rheumatoid arthritis, and autoimmune diseases, etc.
• Understand and sign the consent form of this study

Exclusion Criteria:

• Refuse to sign the consent form, or cannot keep follow-up visit
• Age >70; Age <70, but with multiple organ failure
• Unstable vital signs (breath, blood pressure, pulse)
• Combined with knee ligament (anterior and the posterior cruciate ligament, medial and lateral collateral ligament) rupture, laxity, etc.
• Serious bleeding tendency, poor coagulation function (PTA <35%)
• Pregnant or breast feeding women, or positive pregnancy test in 7 days before treatment
• Participate other clinical experiments in 3 months
• With progressing malignant tumor
• Combined with shock and critically ill patients
• With mental disease, cannot
• With history of knee joint infection, surgery, and radiotherapy
• With immunosuppressive agents treatment in 6 weeks
• Injection with hormones and sodium hyaluronate in joint in 3 months
• Overweight expressed as body mass index (BMI) >35
• With skin disease around knee joint
• With Immunodeficiency disease, including long term use immunosuppressive agents patients
• Combined with serious infection
• With some other conditions that doctor propose not to participate