K.E.M. Radiology

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Department of Radiology 

  Seth G.S. Medical College and K.E.M. Hospital, Mumbai , India

Interventional Case Record

< Case 45 : April 2024 >

 Contributed by : Anjali Methre

Genicular artery embolization for knee pain in a patient with osteoarthritis : A novel technique

Introduction:

Osteoarthritis of the knee is one of the leading causes of knee pain and disability in adults, with a prevalence as high as 28 % in the Indian population [1]. Most patients with mild to moderate symptoms are treated with non-steroidal anti-inflammatory drugs and physiotherapy, with knee arthroplasty generally reserved for severe cases. Surgical intervention is an established technique for end-stage osteoarthritis. However, patients with mild to moderate osteoarthritis may not be ideal surgical candidates due to associated co-morbidities or low disease severity, and pain-relief in these patients may be a challenge [2].

            Genicular artery embolization (GAE) is a recently advocated treatment modality for osteoarthritis, which involves selective cannulation of the abnormal genicular arteries by endovascular approach followed by embolized using particulate materials to reduce the hypervascularity of an osteoarthritic knee joint. [5,6]. 

Case presentation: 

A 51-year-old woman presented with complaint of pain in both knee joints (R>L) for two years more on medial aspect of right knee joint.The pain was insidious in onset, gradually progressive in nature and aggravated during activity. There was joint effusion and stiffness. The patient had been conservatively managed with NSAIDS (Oral and injectables). 

On examination. there is swelling and tenderness over medial aspect of right knee. Her blood parameters were within normal limits. 

Radiological findings: 

The frontal and lateral radiographs of the knee joint show narrowing of the medial joint space with subchondral sclerosis and marginal osteophytes. There are a few subchondral cysts. (Kellgren and Lawrence classification grade III). (Figure 1) 

Fig 1:

Radiograph of right knee standing AP and Lateral view showing Grade III Kellgren and Lawrence classification - medial joint space loss, osteophytosis and subchondral sclerosis.

 The patient was managed conservatively  with NSAIDS (Oral and injectables) but there was no relief of symptoms. Owing to the young age surgical management was not offered and she was referred to interventional radiology for genicular artery embolization. Her pre procedure WOMAC score was 47 and VAS pain score was 7.

 Interventional technique:

             The left common femoral artery access was used. We started with a cobra catheter and exchanged it for a H! catheter. It was advanced upto the right mid third segment of superficial femoral artery.  The DSA showed synovial enhancement on right medial joint space with supply from right descending genicular artery and right branch of sural artery. (Figure 2a and 2b) . Color coded demonstration of arterial anatomy over the DSA angiogram image is shown below (figure 2c)

Figure 2a and 2b- DSA angiogram of right superficial femoral artery and popliteal artery with 4F H1 catheter from distal third segment demonstrate prominent descending genicular artery and branch of sural artery.

Figure 2c- Colour coded DSA anatomical angiogram demonstrating images showing- descending genicular artery (yellow), superior medial genicular artery (green), superior lateral genicular artery (blue) and branch of sural artery (violet).

Following this, super selective cannulation of right descending genicular artery was done and angiogram was taken showing synovial enhancement on medial joint space. (figure 3a). We have applied ice pack over the knee joint region prior to embolization to prevent skin region ischemic phenomenon. Particle embolization was done using 100-micron embosphere particle mixed with contrast. Post embolization angiogram shows no evidence of any synovial enhancement on medial side of joint space. (figure 3b)

Figure 3a- Super selective angiogram of the right descending genicular artery using microcatheter showing synovial enhancement on the medial side.

Figure 3b- Post embolization super selective angiogram of the right descending genicular artery using microcatheter showing no synovial enhancement on the medial side.

Similarly, super selective catherisation of the right branch of the sural artery was performed. The angiogram showed synovial enhancement in the medial joint space. (figure 4a). We applied ice pack over the knee joint region prior to embolization to prevent skin ischemia Particle embolization was done using 100-micron embosphere particle mixed with contrast. Post embolization angiogram shows no synovial enhancement on the medial side of the joint space. (figure 4b)

Figure 4a- Super selective angiogram of branch of sural artery using microcatheter showing synovial enhancement on medial side.

Figure 4b- post embolization super selective angiogram of branch of sural artery using microcatheter showing no evidence of any synovial enhancement on medial side.

Post embolization angiogram showed resolution of synovial enhancement of the medial joint space. (figure 5). The post procedure day 1, 1 week and 1 month WOMAC score were respectively 44, 40 and 38. Similarity post procedure day 1, 1 week and 1c month VAS score were 6, 4 and 3 respectively.

Fig 5 

Figure 5- DSA Angiogram after particle embolization obtained with 4F H1 catheter from distal third segment demonstrating reduced synovial enhancement on medial side.

Discussion:

Earlier considered a degenerative disease, the pathophysiology and disease progression of osteoarthritis are now considered to be multifactorial, with inflammation being an important factor for joint pain and disease progression. Multiple inflammatory mediators, such as interleukins, growth factors, nitric oxide, prostaglandins, and complement factors, have been associated with chronic synovitis. This leads to synovial neoangiogenesis, which in turn contributes to osteophyte formation, cartilage destruction, and a painful knee [3, 4].

In osteoarthritis, the medial joint compartment involvement is 5 to 10 times more common than the lateral. Therefore, the medial and descending genicular arteries are the more common targets for embolization procedures. It is important to know the blood supply of the knee joint and the exact artery supplying the region of blush. The middle genicular artery is the main supply to the anterior and posterior cruciate ligaments. The inferomedial and lateral genicular artery provide vascularization to the patella (Figure 6a).

The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score is used for analyzing the progress of osteoarthritis and accessing post-treatment response (Figure 6b).





Figure 6a- Anatomy of knee joint blood supply.

Figure 6b- The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scoring table. 

The whole organ magnetic resonance imaging score (WORMS) of the knee is a semi quantitative scoring method for multi feature whole organ evaluation of the knee in OA, is valuable in pre and post GAE evaluation. WORMS includes 14 features: articular cartilage integrity, subarticular cysts, subarticular bone attrition, marginal osteophytes, medial and lateral meniscal integrity, anterior and posterior cruciate ligament integrity, medial and lateral collateral ligamental integrity, synovitis, intraarticular loose bodies and periarticular cysts . Large bone marrow lesions and severe meniscal injuries on MR imaging as well as high KL grades indicate poor response to GAE.

Grading of osteoarthritis is done on plain radiographs using Kellgren and Lawrence classification [14], as follows:  

Grade 0: No radiographic changes of osteoarthritis

Grade 1: Doubtful joint space narrowing and possible osteophytic lipping

Grade 2: Definite osteophytes and possible joint space narrowing

Grade 3: Moderate/ multiple osteophytes, Definite narrowing of joint space, Mild Sclerosis, Possible Deformity 

Grade 4: Severe, Large osteophytes, Marked narrowing of joint space, Severe sclerosis and Definite deformity.

        Genicular artery embolization (GAE) is a recently advocated treatment modality for osteoarthritis. This involves selective catheterization of the abnormal genicular arteries by an endovascular approach followed by embolization using particulate materials to reduce the hypervascularity of an osteoarthritic knee joint [5, 6].  Selectively targeting angiogenesis, GAE reduces pain and inflammation in the knee joint [7].  Previously advocated for the treatment of post-operative and post-traumatic refractory hemarthrosis of the knee joint with successful and safe embolization [8], GAE serves as a minimally invasive technique for mild to moderate knee osteoarthritis before knee arthroplasty if patients are non-compliant with initial medical management (Kellgren and Lawrence classification grade II and III cases).

A randomized controlled trial by Bagla et al. showed significant reduction in pain and disability after GAE [9]. A study by Okunu et al. in 95 knees (of 72 patients) resistant to conservative treatment showed a clinical success of 86.3% at 6 months, with documented improvement in synovitis on MRI imaging [10]. A systemic review and meta-analysis of 225 patients by Torkian et al. showed GAE to have good efficacy with no reported serious complications [11].

Complications related to genicular artery embolization include self-limiting skin discoloration and puncture-site groin hematoma. These can be managed conservatively [12, 13]. Multiple other studies have shown that GAE has been advocated as a safe, effective method for reduction in short and intermediate term pain with no significant adverse effects [5, 8, 12, 13, 14].

Patient inclusion criteria for this procedure include: 1) Patients symptomatic for at least six months despite medical management and physiotherapy and 2) radiograph with Kellgren and Lawrence classification grade II and III cases.

Selective intra-arterial embolization of the geniculate arteries will embolize hypervascular segments related to the location of pain, causing reduction in synovial blood supply, decreased neovascularity, and decreased pain. There are two methods for embolization [12, 13, 14].

Temporary embolization by Imipenem/Cilastin (IPM/CS) - 0.5-gram IPM/CS suspended in 5-10 mL of contrast.

Permanent embolization by: * Particles (PVA or embosphere) - Particles size <300 μm have higher risk of skin ischemia and can cause skin color changes; hence, a recommended size is <100 μm. * Coils (proximal embolization)

Conclusion:

Genicular artery embolization is a newer modality of treatment in patients with osteoarthritis of the knee.

A conventional radiograph plays an important role in diagnosing the disease and looking for its progression.

Hypervascularity results in inflammation and pain; GAE is an option to reduce vascularity with good long-term clinical success.

Genicular artery embolization is safe and effective for reduction of pain due to osteoarthritis.

The appropriate patient population for OA is still unclear, but the clinical success rate is better for those with mild to moderate OA than for those with severe OA.

Pain reduction from genicular artery embolization for OA may also reduce opioid, NSAID, and the use of other pain management techniques.

References:

1. Pal CP, Singh P, Chaturvedi S, Pruthi KK, Vij A. Epidemiology of knee osteoarthritis in India and related factors. Indian journal of orthopaedics. 2016 Oct;50(5):518-22.

2. Smith TO, Purdy R, Lister S, Salter C, Fleetcroft R, Conaghan PG. Attitudes of people with osteoarthritis towards their conservative management: a systematic review and meta-ethnography. Rheumatology international. 2014 Mar;34(3):299-313.

3. Ashraf S, Wibberley H, Mapp PI, Hill R, Wilson D, Walsh DA. Increased vascular penetration and nerve growth in the meniscus: a potential source of pain in osteoarthritis. Ann Rheum Dis 2011; 70:523–529.Mobasheri A, Batt M. 

4. An update on the pathophysiology of osteoarthritis. Annals of physical and rehabilitation medicine. 2016 Dec 1;59(5-6):333-9.

5. Landers S, Hely R, Page R, Maister N, Hely A, Harrison B, Gill S. Genicular Artery Embolization to Improve Pain and Function in Early-Stage Knee Osteoarthritis—24-Month Pilot Study Results. Journal of Vascular and Interventional Radiology. 2020 Sep 1;31(9):1453-8.

6. 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. Journal of Vascular and Interventional Radiology. 2020 Jul 1;31(7):1096-102.

7. Mapp PI, Walsh DA. Mechanisms and targets of angiogenesis and nerve growth in osteoarthritis. Nature Reviews Rheumatology. 2012 Jul;8(7):390-8.

8. Yamagami T, Yoshimatsu R, Miura H, Arai Y, Terauchi R, Nakagawa S, Yamada K. Selective arterial embolization with gelatin particles for refractory knee hemarthrosis. Diagn Interv Radiol. 2013 Sep-Oct;19(5):423-6. doi: 10.5152/dir.2013.13063. PMID: 23846552.

9. 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. Journal of Vascular and Interventional Radiology. 2022 Jan 1;33(1):2-10.

10. Okuno Y, Korchi AM, Shinjo T, Kato S, Kaneko T. Midterm clinical outcomes and MR imaging changes after transcatheter arterial embolization as a treatment for mild to moderate radiographic knee osteoarthritis resistant to conservative treatment. Journal of Vascular and Interventional Radiology. 2017 Jul 1;28(7):995-1002.

11. Torkian P, Golzarian J, Chalian M, Clayton A, Rahimi-Dehgolan S, Tabibian E, Talaie R. Osteoarthritis-related knee pain treated with genicular artery embolization: a systematic review and meta-analysis. Orthopaedic Journal of Sports Medicine. 2021 Jul 12;9(7):23259671211021356.

12. Casadaban LC, Mandell JC, Epelboym Y. Genicular artery embolization for osteoarthritis related knee pain: a systematic review and qualitative analysis of clinical outcomes. CardioVascular and Interventional Radiology. 2021 Jan;44(1):1-9.

13. Little MW, Gibson M, Briggs J, Speirs A, Yoong P, Ariyanayagam T, Davies N, Tayton E, Tavares S, MacGill S, McLaren C. Genicular artEry embolizatioN in patiEnts with oSteoarthrItiS of the knee (GENESIS) using permanent microspheres: interim analysis. Cardiovascular and Interventional Radiology. 2021 Jun;44(6):931-40.

14. Padia SA, Genshaft S, Blumstein G, Plotnik A, Kim GH, Gilbert SJ, Lauko K, Stavrakis AI. Genicular Artery Embolization for the Treatment of Symptomatic Knee Osteoarthritis. JBJS Open Access. 2021 Oct;6(4).