Genicular Artery Embolization as Pain Treatment of Knee Osteoarthritis

Inclusion Criteria: * Body Mass Index \< 35 kg / m2. * X-ray verified mild to moderate KOA (Kellgren Lawrence grade 1-3 \[24\]), obtained maximum 6 months prior to inclusion. * Moderate to severe knee pain during walking (Visual Analog Scale (VAS) \> 50 mm) - resistant to minimum 3 months physiotherapy. * Willing, able, and mentally competent to provide informed consent. Exclusion Criteria: * Local infection in knee or groin areas. * Moderate to severe pain in ipsilateral lower limb joints; VAS \> 2. * Intermittent claudication. * Rheumatoid arthritis or seronegative arthropathies. * Prior ipsilateral open knee surgery. * Ipsilateral arthroscopy within 6 months. * Ipsilateral intra-articular knee injection within 6 months. * Current/recent (within 4 weeks) use of oral corticosteroids. * Generalized pain syndrome (e.g. fibromyalgia) or nerve root compression syndromes. * Pregnant or planned pregnancy during the study period. * Lactation. * Active malignancy. * Known history of allergy to contrast media. * Contra-indications for MRI (e.g. metallic foreign bodies, etc). * Manifest hyperthyroidism. * Diabetes (I+II). * Liver disease. * Only one kidney, former kidney surgery, reduced kidney function or failure (chronic or acute). * Estimated glomerular filtration rate \< 60 ml / min / 1.73 m2 (All participants: blood sample maximum 30 days prior to GAE. Participants \> 60 years: another blood sample maximum 3 months prior to last MRI scan with contrast agents). * INR \> 1.4, Platelets ≤ 40 x 109 / l (All participants: blood sample maximum 30 days prior to GAE). * Antithrombotic treatment except acetylsalicylic acid. * Diseases affecting the bone metabolism (E.g. severe osteoporosis, Paget's disease, or hyperparathyroidism). * American Society of Anesthesiologists classification \> 3.