Allogenic Mesenchymal Stem Cell Intraarticular Injection for Knee Osteoarthritis Therapy

Inclusion Criteria: * Chronic knee pain (defined for at least 6 months with NRS 4 or above when pain worst) * Patients with Grade II-III osteoarthritis according to the Kellgren Lawrence Classification and a joint width space of 1-3 mm. * Axial hip, knee, ankle x-ray with no more than 5 degrees valgus/varus deformity * Medial, lateral or dual compartment OA as determined above * BMI \<35 * Danish speaker * Patients must be legally competent and must be able to sign the written consent Exclusion Criteria: * Severe Osteoarthritis (Grade IV according to Kellgren Lavrence Classification) * Intraarticular tumor, infection or fracture * Pregnancy and breast feeding * Cognitive impairment * Treatment with cytostatic drugs * Previous intraarticular knee injection in the past 3 mo. * Unable to perform MRI scan (non-compatible implants, claustrophobia and severe obesity(\>BMI 35) * Previous ligament reconstruction * Meniscal operation with resection with more than 50% or multiple meniscal operations (more than one resection) * Diabetes mellitus type 1 and 2 * Knee instability on physical examination * History of allergy to antibiotics * Concomitant severe infection, malignant tumor, coagulation diseases or uncontrolled or unmanaged systemic disease * Presence of other types of inflammatory arthritis