Effectiveness and Safety of Embosphere Microspheres for Embolization of the Geniculate Artery for the Treatment of Pain With Known Moderate to Severe Knee Osteoarthritis

Inclusion Criteria:

• Subject has signed informed consent

• Subject is age 40-80

• Subject is able to have an MRI

• Minimum of prior 12 weeks of failed response to conservative therapy for kneeosteoarthritis, which may include one or more of: a) Oral or topical NSAIDS, opioid medications, intra-articular injection ofglucocorticoids or hyaluronic acid, physical therapy.

• Localized tenderness in anterior knee area

• Kellgren-Lawrence grade 1, 2, or 3 as assessed by weight-bearing knee radiographs

• Synovitis present as assessed by WORMS

• VAS >50 mm

• WOMAC score >30

Exclusion Criteria:

• Rheumatoid arthritis

• Local infection of the target knee(s)

• Kellgren-Lawrence grade >3

• Osteonecrosis evident by MRI

• Prior knee arthroplasty

• Allergy to iodinated contrast agents that cannot be managed by prophylaxis

• Hypersensitivity to gelatin products

• Any known condition that limits catheter-based intervention or is a contraindicationto embolization

• Active malignancy other than non-melanomatous skin cancer

• Subject is pregnant, breastfeeding, or pre-menopausal and intending to becomepregnant

• Any other condition related to the subject's health and wellbeing deemedexclusionary in the opinion of the investigator