The purpose of this study is to perform a prospective case series to determine efficacy of transcatheter arterial embolization in treating knee osteoarthritis related pain, improving functionality, and reducing opiate usage in patients with mild to moderate knee osteoarthritis who have failed conservative management.

The Gel-Bead embolization particles will be used to perform geniculate artery embolization (GAE) for the purposes of treatment of osteoarthritis-related knee pain.

Management of mild and moderate knee osteoarthritis is curated to each specific patient and their needs, their quality of life, and desired goals. Weight loss is advised for overweight and obese patients. All patients should attempt extended-duration exercise/physical therapy and realignment therapy. If these conservative lifestyle modifications fail to reduce pain, topical and oral non-steroidal anti-inflammatories are indicated. Escalation of care from here is controversial. Some clinicians opt for adjunctive treatments such as intra-articular injection of steroids or viscosupplementation. Unfortunately, pain alleviation from intra-articular steroids is short-lasting and a recent meta-analysis demonstrated no significant difference between intra-articular hyaluronic acid injection and placebo injection. Finally, weak opioids are an option for patients who continue to have pain despite all the aforementioned treatment measures. Joint replacement is reserved for patients with severe osteoarthritis.

Patients who fail conservative, medical management pose a challenge to clinicians. For decades, there have been no interventions available to these patients between the controversial intra-articular hyaluronic acid injection and joint replacement. Interventional radiology (IR) may provide one possible solution. Geniculate artery embolization (GAE) is a minimally-invasive procedure that has historically been performed for patients with recurrent hemarthrosis. It was recently applied to patients with moderate osteoarthritis refractory to maximal medical management. Several studies have been performed and have found that GAE is safe and improves pain.

Inclusion Criteria:

1. Patients between ages 18 and 75 with moderate/severe knee pain secondary to primary osteoarthritis. Moderate/severe pain will be defined as pain 30 mm to 100 mm on the Visual Analog Pain Scale (where 0 denotes 'no pain' and 100 mm denotes worst pain imaginable')
2. Grade 1, 2, or 3 osteoarthritis on the Kellgren-Lawrence grading scale on knee x-ray in the last 6 months
3. Pain must be refractory to 3 months of medical management (which may include a combination of oral analgesics, intraarticular steroids, viscosupplementation, opioid therapy, etc)
4. Patients willing and able to consent to the study

Exclusion Criteria:

1. Kidney dysfunction defined as an estimated GFR < 60 mL/min
2. Acute knee injury
3. Current local infection
4. Prior ipsilateral knee replacement surgery
5. Infectious or inflammatory arthritis
6. History of contrast allergy resulting in anaphylaxis
7. INR (International Normalization Ratio) > 1.6
8. Platelets < 50,000
9. Significant atherosclerosis that would limit angiography
10. Active malignancy
11. Active pregnancy
12. Appropriate candidate for knee replacement surgery determined by clinical and physical examination
13. Recent within 3 months, or active cigarette user

6 months