Geniculate Artery Embolization: Role in Knee Hemarthrosis and Osteoarthritis

Effectiveness of Genicular Artery Embolization for Reducing Synovitis as Assessed by Contrast-Enhanced MR Imaging in Knee Osteoarthritis: A Pilot Study

PURPOSE

To investigate the impact of genicular artery embolization (GAE) on synovitis in knee osteoarthritis (OA) using contrast-enhanced magnetic resonance (MR) imaging and to assess its predictive role in pain response.

MATERIALS AND METHODS

A single-center retrospective analysis was conducted using contrast-enhanced MR imaging on 33 patients treated with GAE for knee OA between December 2022 and March 2023. MR assessments before the procedure and at 3 months after embolization were utilized in a semiquantitative scoring system for synovitis severity and distribution analysis. Pain and function through Western Ontario and McMaster Universities Osteoarthritis Index and visual analog scale scores were also assessed.

RESULTS

Significant synovitis reduction was noted after GAE, particularly in parapatellar and periligamentous areas. Synovial contrast enhancement scores significantly decreased from 5.1 (SD ± 2.0) to 2.9 (SD ± 2.0) at 3 months (P < .001), with a moderate negative correlation between synovial enhancement scores and pain levels (P = .005).

CONCLUSIONS

GAE significantly reduced synovitis in knee OA, evidenced by contrast-enhanced MR imaging. The correlation between preprocedural synovial contrast enhancement scores and pain relief after the procedure, although promising, requires careful interpretation because of the complex factors affecting pain in knee OA.

Angioembolization in the management of joint pain: current concepts

Joint pain is a common complaint owing to its origin in inflammatory and degenerative joint diseases. Recent research has helped narrow down inadequate angiogenesis as one of the causes. Angioembolization has emerged as a treatment option for this condition when it is refractory to conservative treatment. This review describes angioembolization by elaborating on the mechanism, safety, efficacy, comparative analysis of treatment and the road ahead, in addition to summarizing the existing data on this treatment. The inferences from this review further consolidate transcatheter arterial embolization as one of the prime options for managing joint pain when it is refractory to conservative treatment and label it as one of the most exciting prospects. A limitation of this review is that most of the data were from open label case series or case reports.

Geniculate Artery Embolization for the Treatment of Mild to Moderate Knee Osteoarthritis Improves Pain and Function: A Systematic Review

PURPOSE

To evaluate procedural heterogeneity, patient reported outcomes (PRO), and complications following geniculate artery embolization (GAE) for knee OA.

METHODS

A literature search was performed using PubMed, Embase, and Scopus databases from inception to August 2023 according to the 2020 PRISMA guidelines. Human clinical studies reporting PROs following GAE for treatment of knee OA were included and a qualitative comparison across PROs, procedural descriptions and complications was performed. Study quality was assessed using the Cochrane Collaboration's risk of bias tool and the MINORS criteria. The primary outcome measures included changes in PROs at 12 months and variances in procedural methodology.

RESULTS

A total of 17 studies, consisting of 533 patients and 620 knees were identified. The reported mean improvement at 12 months for VAS pain and WOMAC scores ranged from 10-59 and 35.3-47, respectively. At 12 months, median improvements were observed in KOOS subscales such as Pain (range, 8.3-19.5), QOL (15.49-25.0), Sport (7.5-26.3) and Symptoms (1.8-25.0). Decreasing MCID achievement was observed between the 3 month and 6 month follow-up points. Patients with advanced OA and degenerative findings on MRI exhibited lower rates of MCID achievement. Transient adverse events occurred in up to 80% of patients. Limited evidence from serial MRI assessments suggests that GAE improves levels of synovitis. Significant heterogeneity exists among the GAE methodology as 4 different definitions of technical success, 4 distinct embolization targets and use of 5 embolization agents were noted.

CONCLUSION

GAE results in short-term improvements in pain and function with decreasing MCID achievement observed after 3 to 6 months. Patients with severe OA also demonstrate lower rates of MCID achievement. A high rate of transient complications are reported including skin discoloration and access site hematomas. Significant protocol heterogeneity exists which contributes to variable outcomes.

LEVEL OF EVIDENCE

IV; Systematic Review of Level IV Studies.

Value of interventional radiology and their contributions to modern medical systems

Interventional radiology (IR) is a unique specialty that incorporates a diverse set of skills ranging from imaging, procedures, consultation, and patient management. Understanding how IR generates value to the healthcare system is important to review from various perspectives. IR specialists need to understand how to meet demands from various stakeholders to expand their practice improving patient care. Thus, this review discusses the domains of value contributed to medical systems and outlines the parameters of success. IR benefits five distinct parties: patients, practitioners, payers, employers, and innovators. Value to patients and providers is delivered through a wide set of diagnostic and therapeutic interventions. Payers and hospital systems financially benefit from the reduced cost in medical management secondary to fast patient recovery, outpatient procedures, fewer complications, and the prestige of offering diverse expertise for complex patients. Lastly, IR is a field of rapid innovation implementing new procedural technology and techniques. Overall, IR must actively advocate for further growth and influence in the medical field as their value continues to expand in multiple domains. Despite being a nascent specialty, IR has become indispensable to modern medical practice.

Genicular Artery Embolization: A New Tool for the Management of Refractory Osteoarthritis-Related Knee Pain

Osteoarthritis (OA) of the knee is a prevalent cause of chronic pain and disability, particularly affecting women. While traditionally attributed to chronic wear and tear, recent evidence highlights multifactorial pathogenesis involving low-grade inflammation and neoangiogenesis. Current therapeutic options include physical therapy, pharmacotherapy, and total knee arthroplasty (TKA). However, a subset of patients remain symptomatic despite conservative measures, necessitating the development of minimally invasive interventions. Genicular artery embolization (GAE) emerges as a promising option, targeting neovascularization and inflammatory processes in OA. This paper reviews the pathophysiological basis, patient selection criteria, procedural details, and outcomes of GAE. Notably, GAE demonstrates efficacy in relieving knee pain and improving function in patients refractory to conventional therapy. While further research is warranted to elucidate its long-term outcomes and compare it with existing modalities, GAE represents a novel approach in the management of symptomatic knee OA, potentially delaying or obviating the need for surgical intervention. Here, we synthesize the relevant literature, technical details of the procedure, and future perspectives. Moreover, the success of GAE prompts the exploration of transarterial embolization in other musculoskeletal conditions, underscoring the evolving role of interventional radiology in personalized pain management strategies.

Genicular artery embolization for recurrent hemarthrosis: A case report

A 44-year-old otherwise healthy male with a history of trauma and surgical interventions in his right knee presented to the emergency department with repeated hemarthrosis of the right knee. The patient underwent blood tests, X-rays, and magnetic resonance imaging of the knee. A computed tomography angiography revealed blushing of the synovium of the knee. The patient underwent successful embolization of the genicular artery branches. Hemarthrosis did not recur. The use of genicular artery embolization, in our case, not only successfully addressed recurrent hemarthrosis but also underscores its emerging role in comprehensive patient management. This minimally invasive approach, precisely targeting the vascular supply to the affected synovium, offers an effective alternative where conventional therapies may fall short. Beyond symptom relief, it holds promise for preventing hemarthrosis recurrence, a valuable addition to clinicians' interventions for challenging knee joint bleeding cases. Further investigation in larger cohorts and comparative studies may reveal its broader applicability and long-term efficacy, shaping treatment options for recurrent hemarthrosis.

Selective Genicular Artery Embolization in the Management of Osteoarthritic Knee Pain-A Narrative Review

Many people with pain from osteoarthritis (OA) of the knee are either not ready for surgery or may never be surgical candidates. Genicular artery embolization (GAE) is a new proposed management for those with pain despite maximum medical management. It has historically been used to manage recurrent spontaneous haemarthrosis following total knee replacement, but newer studies are showing a positive effect in managing pre-arthroplasty knee OA. The goal of this review is to summarise current and relevant literature from searches of computerised databases and relevant journals, and analyse their results. Studies included show that GAE has promising outcomes in managing mild to moderate OA knee pain in those who have exhausted at least 3 months of conservative therapy. Most studies show improvements in VAS pain and PROM scores (including KOOS, and/or WOMAC). Minimal adverse effects have been associated in up to two years of follow up, the majority of which are self-resolving. The article précises a concise general procedural technique for performing GAE, as well as comparing and contrasting different embolic agents that may be utilised. GAE shows promising outcomes in management of mild to moderate OA knee pain. In the future, there will need to be higher volume studies to determine effectiveness, suitable candidates, and other potential adverse effects.

Comparative Analysis of Transpedal and Transfemoral Access During Genicular Artery Embolization for Knee Osteoarthritis

PURPOSE

This retrospective study aimed to compare the efficacy and safety of transpedal access (TPA) with transfemoral access (TFA) in Genicular Artery Embolization (GAE).

MATERIALS AND METHODS

60 patients who underwent GAE between January and June 2023, were recruited and outcomes were compared between the TFA (n = 37) and TPA (n = 23) groups. Technical and clinical success rates, complications, and patient-reported outcomes were assessed.

RESULTS

All patients attained a 100% technical success rate, which was defined as the successful selective catheterization and embolization of at least one feeding artery to the knee joint, without encountering any major complications. Minor complications, observed in 12/60 patients (20%), were predominantly manifested as a transient skin discoloration. The TPA group had a comparatively higher (p = 0.008) rate of minor complication than the TFA group. Notably, TPA was associated with a longer duration of the procedure (p = 0.013), duration of fluoroscopy (p = 0.004), increased total air kerma (p = 0.037), dose-area product values (p = 0.021), and a greater incidence of vasospasm (p = 0.018) than TFA. However, TPA patients reported shorter recovery times and less post-procedural discomfort, especially reduced back pain due to postinterventional bedrest (p < 0.001). At the 3-month follow-up, the clinical success rate was similar between the two groups (p = 0.905).

CONCLUSION

TFA is the safer and faster method for GAE, offering fewer complications and reduced radiation exposure. For patients with challenging groin anatomies, however, TPA may provide a valuable alternative.

Challenges and complications and their management of the transarterial microembolization for chronic musculoskeletal pain

Transarterial microembolization (TAME) is an increasingly well-known novel and minimally invasive treatment option for painful chronic musculoskeletal diseases that is gaining popularity. Although the safety and effectiveness of TAME have been established, limited knowledge of intraarticular and musculocutaneous arterial anatomy may lead to challenges and complications. This article aims to present cases illustrating these challenges and complications, based on multicenter experiences and a comprehensive literature review. Furthermore, the article also provides preventive tips, solutions, and follow-up strategies to reduce the learning curve for interventional radiologists and facilitate familiarity with post-TAME follow-up images for diagnostic radiologists. CLINICAL RELEVANCE STATEMENT: This article illustrates the intra- and post-interventional complications of transarterial microembolization (TAME) through detailed pictorial reviews, including how to distinguish them from normal angiographic findings. It provides strategies for their prevention, management, and follow-up, which can further improve clinical outcomes. KEY POINTS: • Transarterial microembolization for chronic musculoskeletal pain may result in intrainterventional challenges (IIC) and postinterventional complications (PIC), and their importance may be underestimated. • The intrainterventional challenges include microarterial perforation, arterial dissection, and catheter tip fracture, whereas postinterventional complications include tissue ischemia-related complications, puncture site hemorrhage, and arterial injury. • Being familiar with the intrainterventional challenges and postinterventional complications may help minimize the procedure risk and improve outcomes.

Combined genicular artery embolization and genicular nerve block to treat chronic pain following total knee arthroplasty

BACKGROUND

Chronic knee pain after total knee arthroplasty (TKA) is a common complication that is difficult to treat. This report aims to highlight the benefit of combining embolotherapy and neurolysis intervention for symptomatic relief of post-TKA pain in a patient with long-standing pain refractory to conservative management.

CASE PRESENTATION

A 77-year-old man who had previously undergone left knee arthroplasty has been grappling with worsening knee effusion and debilitating pain, resulting in limited mobility and progressive musculature deconditioning over a 20-year period. Diagnostic arteriography showed marked diffuse periarticular hyperemia around the medial and lateral joint spaces of the left knee, along with capsular distention. The patient initially underwent microsphere embolization to selectively target multiple branches of the genicular arteries, achieving a 50% reduction in pain at the one-month follow-up. Subsequently, the patient underwent image-guided genicular nerve neurolysis, targeting multiple branches of the genicular nerves, which led to further pain reduction (80% compared to the initial presentation or 60% compared to post-embolization) at the one-month follow-up. This improvement facilitated weight-bearing and enabled participation in physical therapy, with sustained pain relief over the 10-month follow-up period.

CONCLUSION

The combination of genicular artery embolization and genicular nerve block may be a technically safe and effective option for alleviating chronic pain after total knee arthroplasty.

Value of Edema-like Marrow Signal Intensity in Diagnosis of Joint Pain: Radiologists' Perspective

Musculoskeletal pain is a significant contributor to disability. The mechanism and target of the treatment should be optimized by imaging, but currently no accepted gold standard exists to image pain. In addition to end-organ pathology, other mediators also contribute to nociception, such as angiogenesis, axonal extension, immunologic modulation, and central sensitization. Recent research indicates that local inflammation is a significant contributor to pain in the extremities; therefore, we focus here on edema-like marrow signal intensity (ELMSI). We examine both the relevance of ELMSI for pain and novel imaging techniques.

Evaluating the Safety and Effectiveness of Quick-Soluble Gelatin Sponge Particles for Genicular Artery Embolization for Chronic Knee Pain Associated with Osteoarthritis

PURPOSE

To evaluate the effectiveness and safety of genicular artery embolization (GAE) using quick-soluble gelatin sponge particles (QS-GSPs) to alleviate chronic knee pain associated with osteoarthritis.

MATERIALS AND METHODS

This retrospective study included 71 patients (97 procedures, including 26 patients for both knees) who underwent GAE to treat osteoarthritic knee pain between August 2019 and January 2022. QS-GSPs were used for all the procedures. Technical success was defined as the embolization of at least 1 feeding artery. Clinical outcomes were evaluated using a 10-point visual analog scale (VAS). Clinical success was defined as a decrease in the VAS score of >50%.

RESULTS

The technical success rate was 100% (97 of 97). The mean VAS scores at baseline, immediately after TAE, and at 1 day, 1 week, 1 month, 3 months, and 6 months after TAE were 6.3, 4.3, 5.0, 3.0, 2.9, 2.9, and 2.8, respectively. The clinical success rate was 72% (70 of 97 patients) at 6 months. No major adverse events were reported, and temporary skin color change (50.5%, 49 of 97) and hematoma at the puncture site (10.3%, 10 of 97) were observed.

CONCLUSIONS

GAE using QS-GSPs had a high technical success rate and was considered safe. Clinical outcomes using QS-GSPs were comparable with those of existing materials.

Effectiveness of Geniculate Artery Embolization for Chronic Pain after Total Knee Replacement-A Pilot Study

PURPOSE

To evaluate the efficacy and safety of embolization of hyperemic synovial tissue for the treatment of persistent pain after total knee arthroplasty (TKA).

MATERIALS AND METHODS

Twelve patients with persistent pain after TKA were enrolled in this prospective, single-center pilot study. Genicular artery embolization (GAE) was performed using 75-μm spherical particles. The patients were assessed using a 100-point Visual Analog Scale (VAS) and Knee Injury and Osteoarthritis Outcome Score (KOOS) at baseline and 3 and 6 months thereafter. Adverse events were recorded at all time points.

RESULTS

A mean of 1.8 ± 0.8 abnormal hyperemic genicular arteries were identified and embolized, with a median volume of diluted embolic material of 4.3 mL in all 12 (100%) patients. The mean VAS score on walking improved from 73 ± 16 at baseline to 38 ± 35 at the 6-month follow-up (P < .05). The mean KOOS pain score improved from 43.6 ± 15.5 at baseline to 64.6 ± 27.1 at the 6-month follow-up (P < .05). At the 6-month follow-up, 55% and 73% of the patients attained a minimal clinically important change in pain and quality of life, respectively. Self-limited skin discoloration occurred in 5 (42%) patients. The VAS score increased by more than 20 immediately after embolization in 4 (30%) patients, who required analgesic treatment for 1 week.

CONCLUSION

GAE is a safe method of treating persistent pain after TKA that demonstrates potential efficacy at 12 months.

Pre-operative synovial hyperaemia in haemophilia patients undergoing total knee replacement and the effects of genicular artery embolization: A retrospective cohort study

AIM

Haemophilia is characterized by recurrent joint bleeding caused by a lack of clotting factor VIII or IX. Due to repeated joint bleeding, end-stage arthropathy occurs in relatively young patients. A total knee replacement (TKR) can be a solution. However, TKR may be complicated by perioperative and postoperative bleeds despite clotting factor therapy. The aim of this study was to evaluate the prevalence of pre-operative synovial hyperaemia and the effects of Genicular Artery Embolization on synovial hyperaemia and 3-month postoperative joint bleeding.

METHODS

In this retrospective cohort study, all patients with haemophilia who underwent periarticular catheter angiography between 2009 and 2020 were evaluated after written informed consent. Synovial hyperaemia on angiography was scored by an interventional radiologist.

RESULTS

Thirty-three angiography procedures in 24 patients were evaluated. Median age was 54.4 years (IQR 48.4-65.9). Preoperative synovial hyperaemia was observed in 21/33 joints (64%). Moderate and severe synovial hyperaemia was observed in 10/33 joints (30%). Synovial hyperaemia decreased in 13/15 (87%) joints after embolization. Three-month postoperative joint bleeding occurred in 5/32 joints: in 2/18 joints (11%) without synovial hyperaemia and in 3/14 joints (21%) with mild synovial hypertrophy. Non-embolized and embolized joints did not differ regarding 3-month postoperative bleeding (P = .425). No complications were observed after embolization.

CONCLUSION

One-third of patients with haemophilia requiring a TKR had moderate or severe synovial hyperaemia which can be reduced safely by Genicular Artery Embolization prior to TKR. Three-month postoperative bleeding appears to occur independently of the presence of residual mild synovial hyperaemia.

Knee and Shoulder Vascular Anatomy

In the past decade, angiographic studies have demonstrated neovessels in or in the vicinity of affected joints in many musculoskeletal conditions that used to be considered wear and tear joint disease, such as knee osteoarthritis, frozen shoulder, and overuse injuries. The novelty of this finding is showing the presence of neovascularity at an angiographically detectable level, as compared to histologically evident neovessels that had been discovered years ago. These neovessels have now become the target of interventions in a growing field called muscoskeletal embolotherapy. An in-depth and all-encompassing understanding of the vascular anatomy that could specifically assist performing of these procedures is paramount. Such an understanding will help ensure success in clinical outcomes and avoid much dreaded complications. This review discusses the vascular anatomy relevant to the 2 most commonly performed musculoskeletal embolotherapies, genicular artery embolization and transarterial embolization for frozen shoulder.

Transcatheter Arterial Embolization for Alleviating Chronic Musculoskeletal Pain and Improving Physical Function: A Narrative Review

Chronic musculoskeletal pain imposes immense suffering and diminishes the quality of life for millions of patients worldwide; the pain persists despite the use of standard conservative treatments. Increases in our understanding of the pathophysiological mechanisms underlying musculoskeletal disorders indicate the involvement of inappropriate angiogenesis. Accordingly, the resulting neovessels are the target of emerging treatments for chronic musculoskeletal pain, including transarterial embolization. The use of this noninvasive procedure to treat pain refractory to standard therapy in a variety of musculoskeletal conditions is the focus of numerous recent investigations. Here, we describe the pathophysiological indications for the use of transarterial embolization and summarize the findings of studies investigating its use in a variety of histopathological conditions and anatomical sites.

Endoscopically observed outer membrane of chronic subdural hematoma after endovascular embolization of middle meningeal artery

Background:

Embolization of the middle meningeal artery (MMA) has been established for chronic subdural hematoma (CSDH). Neuroendoscopic observation of the outer membrane of the hematoma was carried out after embolization. The treatment mechanism of embolization is discussed, focusing on the vasculature and inflammation of the membrane.

Methods:

Four patients with recurrent CSDH were included in this study. The MMA was embolized using Embosphere® particles in three patients. The outer membrane was observed with normal and narrow band images (NBIs).

Results:

The net-like vessels were not obstructed in the whole area of the outer membrane, but in a patchy fashion of embolized areas surrounded by nonembolized areas. In two patients, the nonembolized areas showed a hemorrhagic inflammatory red color. Histopathological examination confirmed hypertrophic dura with leukocyte infiltration. Dilated dural arteries and proliferated sinusoid arteries were located in the deep and superficial border cell layers. These arteries were visualized as green and brown on NBI, respectively. In the embolized area, the red membrane turned pink, indicating ischemia and subsiding inflammatory hyperemia. In the third patient, the outer membrane was white in both the nonembolized and embolized areas in endoscopic view, and the net-like vessels were sparse in both endoscopy and histology, indicating a scar inflammatory phase. The membrane transition was not observed in the patient that did not undergo embolization.

Conclusion:

Endoscopic observation revealed that embolization of the MMA blocked both the dural and sinusoidal arteries. Ischemic transformation causing the suppression of inflammation of the outer membrane is a suggested mechanism of MMA embolization.

Emerging Targets for the Treatment of Osteoarthritis: New Investigational Methods to Identify Neo-Vessels as Possible Targets for Embolization

Osteoarthritis (OA) is the major cause of disability, affecting over 30 million US adults. Continued research into the role of neovascularization and inflammation related to osteoarthritis in large-animal models and human clinical trials is paramount. Recent literature on the pathogenetic model of OA has refocused on low-level inflammation, resulting in joint remodeling. As a result, this has redirected osteoarthritis research toward limiting or treating joint changes associated with persistent synovitis. The overall goal of this review is to better understand the cellular and tissue-specific mechanisms of inflammation in relation to a novel OA treatment modality, Genicular Artery Embolization (GAE). This article also assesses the utility and mechanism of periarticular neovascular embolization for the treatment of OA with a particular emphasis on the balance between pro-angiogenic and anti-angiogenic cytokines, inflammatory biomarkers, and imaging changes.