Emerging Topics in Interventional Radiology: The Role of Geniculate Artery Embolization to Treat Knee Osteoarthritis

Continued advancements in minimally invasive catheter-based therapies in interventional radiology has resulted in alternative treatment options for diagnoses that previously required surgery with costly hospital stays and outpatient recovery. For knee osteoarthritis (OA), a disease that negatively affects millions of people worldwide, radiologists not only play a role in diagnosing OA but are involved with image-guided treatment for this condition as well.¹

Geniculate artery embolization (GAE) is a novel minimally invasive therapy performed by interventional radiologists that has demonstrated clinical improvement for OA knee pain. It should be considered as a treatment option for knee OA prior to total knee replacement surgery.

Recognizing the Limitations of Traditional Treatments for Knee Osteoarthritis

Osteoarthritis, the leading cause of disability in older adults, is a degenerative disease associated with chronic inflammation of the joints, most commonly affecting the knee.^1,3-5 Osteoarthritis of the knee clinically presents with pain and dysfunction. Once the condition is diagnosed, regression of damaged tissues is uncommon and current management targets symptom control.⁵ The standard of care treatment begins with conservative measures, including exercise and weight management, which can be difficult for patients to comply with and are commonly clinically ineffective. Subsequent treatment involves pharmacological options, including NSAIDS, which have limited long-term use due to potential complications.^2,4

Total knee arthroplasty is the standard of care for patients with severe osteoarthritis after failure of conservative measures. However, only nine to 33 percent of patients with severe OA are willing to consider total knee arthroplasty.^3,5 Also, most patients with OA are elderly and have multiple comorbidities, which may exclude them as surgical candidates altogether.⁴ Therefore, whether patients are reluctant or ineligible for total knee replacement, there is a large population of patients that could benefit from minimally invasive procedures.

Current minimally invasive treatments include intraarticular injections, which can be performed with imaging guidance by a radiologist. Intraarticular injections have been shown to give patients short-term pain relief but require multiple repeat procedures for continued pain management.⁶ However, there is inconsistent efficacy of intraarticular injections with 20 to 30 percent of patients experiencing no pain relief from intraarticular corticosteroid injections and mixed data on whether intraarticular corticosteroid injections may accelerate the progression of OA.^2,6,7

Weighing the Pros, Cons And Outcomes with Geniculate Artery Embolization

Arterial hypervascularity of the knee joint plays a significant role in the pathogenesis of knee OA and GAE targets this hypervascularity to reduce inflammation and symptomatic knee pain.^2,5

Geniculate artery embolization is a minimally invasive treatment option for knee OA that can be performed with minimal downtime afterward, making it a treatment option for non-surgical candidates or those looking for less invasive treatment options. Also, GAE can be a supplementary treatment option for surgical candidates to prolong the time to total knee replacement. Systematic reviews have shown an 84 to 100 percent technical success rate of the procedure with few minor transient complications.^3,5,7

While there has been evidence of minor complications with GAE, the majority of complications are secondary to non-target embolization of cutaneous vessels, resulting in transient skin discoloration.⁸ Given the novelty of GAE, the knowledge of long-term effects is limited.⁸

Overall, GAE has demonstrated improvement in the clinical symptoms of knee OA. Studies have shown significant reduction in subjective knee pain even in the first week after GAE, which was durable after six months.^2,3,8 In addition to the reduction in pain, researchers have also noted improvement in the patients' functional status and others have documented an impact on clinical symptoms.^1,3,8 Outcomes of GAE were superior for patients with mild to moderate OA in comparison to patients with severe OA.³ The use of GAE demonstrated a reduction in complementary conservative therapy for knee OA with the need for opioids, NSAIDS, and intraarticular hyaluronic acid decreasing by 27 percent, 65 percent and 73 percent respectively.^3,8

Future Directions

New trials evaluating the efficacy of GAE are currently underway. Additionally, there are multiple embolic agents currently being used for GAE that are considered safe although research looking at agent effectiveness and emerging agents is ongoing.⁸ There are developing centers throughout the United States that focus solely on GAE, likely due to the large patient interest to avoid invasive, costly surgery.³ The possibility of GAE to delay OA progression has been hypothesized but not fully evaluated.²

Conclusion

Knee OA affects hundreds of millions of people worldwide and more than 30 million Americans with a prevalence of 10 to 37 percent among adults over the age of 60 years of age in the United States.^1-3 There are numerous palliative techniques and interventions to manage pain associated with knee OA. The current treatment paradigm of OA involves conservative measures and if failed, total knee replacement, leaving a gap in treatment options for the population of patients that are reluctant or unable to undergo total knee replacement and have exhausted other treatment options. The current minimally invasive treatment option of intraarticular injections offers time limited pain relief.

Radiologists are currently involved in diagnosing OA and offering these minimally invasive image-guided intraarticular injections. Radiologists can further bridge the gap between conservative and surgical treatment options with the minimally invasive GAE, which can reduce the use of other conservative therapies as well as prolong the time to total knee replacement.⁴ Given that GAE has demonstrated initial clinical and technical success, increasing awareness of this therapy as a treatment option for knee OA prior to total knee replacement may be useful as research continues to emerge on the safety and effectiveness of this treatment.

References

1. Bagla S, Piechowiak R, Sajan A, Orlando J, Hartman T, Isaacson A. Multicenter randomized sham controlled study of genicular artery embolization for knee pain secondary to osteoarthritis. J Vasc Interv Radiol. 2022;33(1):2-10.e2.

2. Bagla S, Piechowiak R, Hartman T, Orlando J, Del Gaizo D, Isaacson A. Genicular artery embolization for the treatment of knee pain secondary to osteoarthritis. J Vasc Interv Radiol. 2020;31(7):1096-1102.

3. Heller DB, Beggin AE, Lam AH, Kohi MP, Heller MB. Geniculate artery embolization: role in knee hemarthrosis and osteoarthritis. Radiographics. 2022;42(1):289-301.

4. Mora JC, Przkora R, Cruz-Almeida Y. Knee osteoarthritis: pathophysiology and current treatment modalities. J Pain Res. 2018;11:2189-2196. Published 2018 Oct 5. doi:10.2147/JPR.S154002.

5. Taslakian B, Miller LE, Mabud TS, et al. Genicular artery embolization for treatment of knee osteoarthritis pain: systematic review and meta-analysis. Osteoarthr Cartil Open. 2023;5(2):100342. doi:10.1016/j.ocarto.2023.100342.

6. Guermazi A, Neogi T, Katz JN et al. Intra-articular corticosteroid injections for the treatment of hip and knee osteoarthritis-related pain: considerations and controversies with a focus on imaging-radiology scientific expert panel. Radiology. 2020; 297:3, 503–512.

7. Padia SA, Genshaft S, Blumstein G, et al. Genicular artery embolization for the treatment of symptomatic knee osteoarthritis. JB JS Open Access. 2021;6(4):e21.00085. doi:10.2106/JBJS.OA.21.00085.

8. Torkian P, Golzarian J, Chalian M, et al. Osteoarthritis-related knee pain treated with genicular artery embolization: a systematic review and meta-analysis. Orthop J Sports Med. 2021;9(7). doi:10.1177/23259671211021356.