The goal of this randomized clinical trial is to compare treatment for osteoarthritis in the knee using platelet rich plasma (PRP) or adipose stem cells (ADS). The main questions it aims to answer are:

• Will the patients clinically benefit from the treatment, and if so, which treatment is better?
• Will there be radiological findings to support this? Participants will be randomized into one of four groups: PRP, ADS, PRP + ADS or placebo treatment (saline) and will be examined and get an X-ray and MRI of the knee taken at inclusion and after 1 and 2 years.

Patients will be randomized into one of four treatment groups and then be followed up at 6 weeks, 12 weeks, 6 months, 1 year and 2 years after intervention. They will fill out scores and be clinically evaluated, as well as radiologically examined at inclusion and at the final check up (x-ray and MRI).

Inclusion Criteria:

• Symptomatic osteoarthritis in the knee grade I-III using the Kellgren-Lawrance Grading Scale
• Age 40-70 years
• Minimum VAS 3
• No use of NSAIDs or steroids the last 14 days
• No injections of hyaluronic acid the last three months
• Varus/valgus deformity <5 degrees as evaluated on x-ray imaging

Exclusion Criteria:

• Pregnant or breastfeeding women
• Cancer
• Other etiologies of knee pain (refered pain, pain from the back, dislocated meniscus on MRI, osteoarthritis grade IV using the Kellgren-Lawrance Grading Scale)
• Previous knee surgery on the affected knee
• Secondary osteoarthritis in the knee
• Previous infection in the knee
• Other diseases (rheumatoid arthritis, diabetes, systemic diseases or corticosteroid-demaning disease)
• Patients with a high risk of deep vein thrombosis
• Patients who cannot cooperate/are low compliance (psychiatric disease) or has contraindications for MRI

Only main scientists in the project will have access to IPD.