The aim of this study is to investigate the safety and efficacy of geniculate artery embolization (GAE) as pain treatment in patients with mild to moderate knee osteoarthritis.

This is a single arm, prospective, pilot study investigating the safety and efficacy of GAE as pain treatment in patients with mild to moderate knee osteoarthritis. Patient related outcome measurements (PROMs), physical tests and several image modalities will be conducted.

It may form the grounding for further research in the shape of a larger randomized clinical trial.

The hypothesis is, that GAE will reduce synovitis and thereby pain in the patient group. This may secondary improve physical function and reduce consumption of analgesics.

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.