An Exploratory Clinical Study to Investigate the Effect of autoSTEM-OA and alloSTEM-OA in Participants With Knee Osteoarthritis

Inclusion Criteria: 1. Informed consent obtained before any study-related activities. Study-related activities are any procedures that are carried out as part of the study, including activities to determine suitability for the study. 2. Male or female, aged 18 - 60 years (both inclusive) at the time of informed consent. 3. Joint pain ≥ 30mm on 100mm VAS at screening 4. Grade 2-3 Kellgren Lawrence OA on radiograph with no full-thickness lesion \>1 cm in any dimension by x-ray 5. Failure of minimum 2 nonoperative therapies (oral pain medications, physical therapy, corticosteroid injection, or viscosupplementation injection) 6. Body mass index (BMI) within the range 18 - 35 kg/m2 (both inclusive) 7. Minimum 200 ml of fat (lipoaspirate) available for liposuction at the abdomen and/or thighs as judged by the investigator. 8. Agree to donate cells to alloSTEM-OA participants. 9. Fulfils eligibility criteria for allogeneic cell- and tissue donors. 10. Speaks and reads Danish or English Exclusion Criteria: 1. Active tobacco use, or use of other nicotine substitutes 2. Active cancer or still in follow-up (5 years) 3. Rheumatologic disease 4. Avascular disease 5. Severe bone deformity 6. Previous infection of the knee joint 7. Pes anserine bursitis 8. pain attributed to diffuse edema 9. pain attributed to displaced meniscal tear or osteochondritis 10. Neurogenic or vascular claudication 11. Bleeding disorders 12. Chemotherapy 13. Radiation therapy to the leg or adipose harvested site 14. Knee injections within 3 months of treatment 15. Unable to discontinue the following drugs 7 days before injections (prescription pain medication, anticoagulation medicine (including ibuprofen), thrombolytics, antiplatelet medication) 16. Use of oral glucocorticoids. 17. Female who is pregnant, breast-feeding or intends to become pregnant within 1-year after the treatment, or is of child-bearing potential and not using highly effective contraceptive method. 18. Known chronic disease associated with metabolism malfunction or poor healing. 19. Allergy towards necessary anaesthesia 20. Varus/valgus malalignment \>5° 21. Isolated patellofemoral arthrosis