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

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.

Transcatheter Arterial Embolization for Chronic Prostatitis/Chronic Pelvic Pain Syndrome: A Retrospective Study of 44 Patients

PURPOSE

To investigate the preliminary treatment outcomes of transcatheter arterial embolization (TAE) for chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS).

MATERIALS AND METHODS

This retrospective study included patients with refractory CP/CPPS who underwent TAE between April 2022 and February 2023. All patients had persistent pelvic pain for at least 3 months, a total score of at least 15 on the NIH-Chronic Prostatitis Symptom Index (NIH-CPSI), and lacked evidence of infection. All procedures were performed by injecting imipenem/cilastatin sodium (IPM/CS) from bilateral prostatic arteries ± internal pudendal arteries. NIH-CPSI, pain numeric rating scale (NRS), and complications were evaluated at 1, 3, and 6 months after the initial TAE and at the final follow-up.

RESULTS

Out of 48 patients, 44 were included in this study, with four excluded because of loss of follow-up. No severe procedure-related complications were observed. Pretreatment and post-treatment evaluations at 1, 3, and 6 months after the initial TAE and at the final follow-up (mean 16.6 months) revealed a decrease in the mean NIH-CPSI scores from 27 ± 6 to 21 ± 8, 20 ± 9, 17 ± 9, and 18 ± 9, respectively (all P < 0.001). Pain NRS scores were also decreased from 7.0 ± 1.6 to 4.8 ± 2.5, 4.1 ± 2.6, 3.7 ± 2.4, and 3.4 ± 2.3, respectively (all P < 0.001). The proportions of clinical success, defined as a reduction of at least 6 points from baseline in the NIH-CPSI, at 6 months after TAE and at the final follow-up were 70 and 64%, respectively.

CONCLUSIONS

This study provides evidence of the feasibility of TAE using IPM/CS for CP/CPPS, suggesting both symptomatic improvement and safety.

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.

Minimally invasive interventional procedures for osteoarthritis and inflammatory arthritis: A systematic review and meta-analysis

OBJECTIVE

to summarize the evidence on the efficacy of minimally invasive interventional procedures such as radiofrequency ablation (RFA) and transcatheter arterial embolization (TAE) in patients with osteoarthritis or inflammatory arthritis.

METHODS

a literature search was conducted in PubMed and Web of Science databases. Both randomized controlled trials (RCTs) and non-randomized studies of interventions (NRSI) were included. The results were organized according to the treated anatomical site: knee, hip, foot and ankle, shoulder, hand and wrist, sacroiliac joints. Data about treatment efficacy were extracted. The main outcome was change in pain intensity using the 0-10 visual analog scale (VAS) from baseline to 1 month. Additional timepoints at 3, 6 and 12 months were assessed. Change in functional status was evaluated. Pooled estimates were calculated as the mean difference (MD) and 95 % confidence interval relative to baseline. The meta-analyses of RCTs and NRSI were conducted separately.

RESULTS

of the 4599 retrieved articles, 164 were included in the review and, considering all the established timepoints, 111 (38 RCTs and 73 NRSI) were selected for the meta-analysis. Only one article described patients with inflammatory arthritis. In the meta-analysis of RCTs, one month after the procedure, MD in VAS was -3.98 (-4.41 to -3.55; k = 21) for knee RFA, and -3.18 (-3.96 to -2.39; k = 8) for sacroiliac joints RFA. In the meta-analysis of NRSI, MD in VAS was -4.12 (-4.63 to -3.61; k = 23) for knee RFA, -3.84 (-4.77 to -2.92; k = 7) for knee TAE, -4.34 (-4.96 to -3.71; k = 2) for hip RFA, -3.83 (-4.52 to -3.15; k = 3) for shoulder RFA and -4.93 (-5.58 to -4.28; k = 14) for sacroiliac joints RFA. Significant decrease in pain intensity was found also at 3, 6 and 12 months. Additionally, functional status improved at all the assessed timepoints.

CONCLUSION

minimally invasive interventional procedures can improve pain and functional status of patients affected by OA or chronic sacroiliac pain of degenerative origin. Further research is warranted in the field of inflammatory rheumatic diseases.

Comparing technical success and clinical outcomes of macrocatheter versus microcatheter in genicular artery embolization for knee osteoarthritis

PURPOSE

The purpose of this study was to evaluate the comparative effectiveness and safety of using macrocatheters versus microcatheters for genicular artery embolization (GAE) in the management of knee osteoarthritis (OA). The primary outcomes were technical success and adverse events during and immediately after the procedure. The secondary outcome was the clinical outcome over the follow-up period.

MATERIALS AND METHODS

In our retrospective analysis, we included 79 patients undergoing GAE for OA. Patients were categorized based on the catheter type used: microcatheter through macrocatheter or directly through macrocatheter. Key parameters, including technical success, adverse events, procedure duration, radiation exposure, and clinical outcomes (VAS and WOMAC scores), were assessed at 1st, 3rd, and 6th-month intervals.

RESULTS

Technical success stood at 100 % for the microcatheter group, with a slight reduction for the macrocatheter group at 91 % (p = 0.069). Procedure and fluoroscopy durations were significantly shorter in the macrocatheter group (p < 0.001). Additionally, the macrocatheter group demonstrated a marked reduction in radiation dose, with notably decreased air kerma values. Clinical outcomes, including VAS and WOMAC scores at the predefined intervals, revealed no significant disparities between the two cohorts.

CONCLUSION

In GAE procedures utilizing a temporary embolic agent (imipenem/cilastatin), initiating the intervention with a macrocatheter can be deemed cost-effective, safe and advantageous for patients with less complex vascular anatomy, as it significantly reduces procedural and fluoroscopy times, thereby minimizing radiation exposure. Conversely, in patients with intricate vascular pathways, transitioning to a microcatheter enhances technical success.

Society of Interventional Radiology Research Reporting Standards for Genicular Artery Embolization

Genicular artery embolization (GAE) is an emerging, minimally invasive therapy to address the global burden of knee osteoarthritis (OA) and the unmet needs for medically refractory disease. Although total knee arthroplasty has been a standard intervention for severe cases, GAE is developing into a promising alternative, particularly for patients ineligible for or unwilling to undergo surgery. GAE targets the inflammatory cascade underlying OA pathophysiology by arresting neoangiogenesis and preventing pathological neoinnervation, offering potential pain relief. Although early studies have established safety and short-term effectiveness, ensuing studies are needed to validate long-term safety, durability, and comparative effectiveness and to optimize patient selection, embolic agent selection, and administration techniques. Standardized reporting guidelines are therefore essential to enhance transparency and reproducibility across clinical trials, facilitating data aggregation and comparison. This Society of Interventional Radiology (SIR)-endorsed reporting standards consensus document provides a framework to harmonize future research efforts and to improve the interpretation of outcomes.

Transarterial Embolization of Geniculate Arteries Reduces Pain and Improves Physical Function in Knee Osteoarthritis-A Prospective Cohort Study

Knee osteoarthritis (OA) affects millions worldwide, leading to pain and reduced quality of life. Conventional treatments often fail to provide adequate relief, necessitating new therapeutic approaches. This study evaluated the efficacy and safety of genicular artery embolization (GAE) using permanent microspheres in patients with mild-to-moderate knee OA. In this prospective, single-center study, 17 participants underwent GAE. KOOS (Knee injury and Osteoarthritis Outcome Score), WOMAC (The Western Ontario and McMaster Universities Arthritis Index), and IPAQ (International Physical Activity Questionnaire) scores, along with physical performance tests, medication use, and dual-energy X-ray absorptiometry (DEXA) scans, were assessed at baseline and at multiple follow-up points over six months. The primary endpoint, VAS at six months, showed significant improvement (median reduction from 66 mm to 40 mm, p = 0.0004). All pain and function scores, as well as physical performance tests, improved significantly. No clinically relevant changes in medication use or DEXA parameters were observed after six months. Only minor, self-limiting adverse events occurred. This study indicates that GAE is a promising minimally invasive treatment for knee OA, providing significant pain relief and functional improvement. However, further long-term, randomized trials are needed to confirm these findings and establish optimal patient selection criteria.

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.

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.

Genicular Artery Embolization: Embolic Material and Imaging Review

Osteoarthritis (OA) of the knee is a degenerative condition impacting numerous individuals globally. Genicular artery embolization (GAE) has emerged as an effective minimally invasive therapy for managing medically refractory OA-related pain in patients who are not eligible for surgery. This intervention works by disrupting the inflammatory and neoangiogenic pathways that contribute to pain. The efficacy of GAE has been demonstrated in various clinical trials, yielding promising results. This review aims to explore recent advancements in the embolic materials used during GAE, examining their properties and potential benefits. Additionally, it will describe the use of pre-, intra-, and postprocedural imaging-particularly magnetic resonance imaging and other modalities-to optimize GAE outcomes.

Advanced Interventional Procedures for Knee Osteoarthritis: What Is the Current Evidence?

The prevalence of knee osteoarthritis (OA) is the highest among all joints and likely to increase over the coming decades. Advances in the repertoire of diagnostic capabilities of imaging and an expansion in the availability and range of image-guided interventions has led to development of more advanced interventional procedures targeting pain related to OA pain while improving the function of patients presenting with this debilitating condition. We review the spectrum of established advanced interventional procedures for knee OA, describe the techniques used to perform these procedures safely, and discuss the clinical evidence supporting each of them.

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.

Effect of isometric quadriceps exercise on local microcirculation of the infrapatellar fat pad in female patients with knee osteoarthritis

OBJECTIVE

To elucidate the local microcirculation of the infrapatellar fat pad (IFP) in patients with knee osteoarthritis (KOA) by determining the changes in IFP hardness and hemoglobin concentration during isometric quadriceps exercise (IQE).

DESIGN

In this observational cross-sectional study, patients diagnosed with bilateral KOA were included in the KOA group (30 knees), healthy older adults in the control group (20 knees), and younger adults in the young group (20 knees). Ultrasonography was performed at rest and during IQE to measure IFP hardness based on shear wave velocity. Near-infrared spectroscopy was performed to measure oxygenated hemoglobin (O2Hb), deoxygenated hemoglobin (HHb), and total hemoglobin (cHb) in the IFP before (Baseline), during (IQE task), and after IQE (Post). IFP hardness and O2Hb, HHb, and cHb concentration were analyzed using a linear mixed model for the groups and measurement points.

RESULTS

During IQE, IFP hardness changes were significantly less in the KOA group than in the other groups (KOA: 95 % confidence intervals (CIs) [-0.854, 0.028]; control: 95 % CI [-0.941, -0.341]; and young: 95 % CI [-2.305, -1.706]). In the KOA group, O2Hb concentration exhibited no significant changes at Post compared with Baseline; however, significant changes were observed in the other groups (KOA: 95 % CI [-1.176, 0.423]; control: 95 % CI [-1.452, -0.276]; and young: 95 % CI [-4.062, -2.102]).

CONCLUSIONS

During IQE, changes in hardness and hemoglobin concentration in the IFP were not significant in the KOA group, suggesting impaired local microcirculation of the IFP.

Genicular Artery embolisation in Patients with Osteoarthritis of the Knee (GENESIS) Using Permanent Microspheres: Long-Term Results

PURPOSE

To report the 2-year follow-up of patients with mild-to-moderate knee osteoarthritis (OA) treated with genicular artery embolisation (GAE) as part of the GENESIS study.

MATERIALS AND METHODS

Forty-six patients, median age = 60 (45-83) underwent GAE using permanent microspheres (100-300 μm). Technical success was defined as embolisation of the targeted genicular arteries. Knee Injury and Osteoarthritis Outcome Score (KOOS) and Visual Analogue Scale (VAS) (0-100 mm) were recorded at baseline, 6 weeks, 3 months, 1, 2 years. Contrast-enhanced MRI knee scans were acquired at baseline and 1 year, and evaluated with the Whole-Organ Magnetic Resonance Imaging Score (WORMS). Functional MRI brain imaging and psychometric assessments were undertaken to investigate correlation between neuropsychological phenotypes and clinical outcome. Adverse events were recorded prospectively.

RESULTS

Technical success was achieved in forty patients (87%). Mean VAS improved from 58.63 (SD = 20.57, 95% CI 52.7-65.5) at baselines to 37.7 at 2-years (SD = 26.3, 95% CI 27.0-47.5). Whole and subgroup KOOS were significantly improved at each timepoint with associated reductions in analgesia usage. WORMS analysis demonstrated significant reduction in synovitis (p < 0.05) with no cases of osteonecrosis. Self-limiting skin discolouration occurred in four patients. A self-limiting groin haematoma and single case of deep-vein thrombosis due to immobilisation were also recorded. Nine patients subsequently underwent knee arthroplasty with no additional operational complexities identified. Neuropsychometric assessment elucidated a correlation between baseline catastrophising and greater reduction in pain post GAE.

CONCLUSION

GAE is a safe intervention for mild-moderate knee osteoarthritis, with sustained efficacy at 2 years. These results are promising and justify ongoing controlled trials.

Posterior Tibial Artery Blood Flow Velocity Is Increased in Patients with Plantar Heel Pain

Background/Objectives: This study aimed to investigate the relationship between posterior tibial artery blood flow velocity and plantar heel pain (PHP). Methods: The PHP group comprised patients diagnosed with plantar fasciitis with plantar heel pain during gait, and the control group comprised healthy participants without plantar heel pain. The peak systolic velocity of the posterior tibial artery was measured using ultrasonography; it was measured three times on each side, and the mean value was calculated. Receiver operating characteristic curve analysis was performed to calculate the peak systolic velocity cutoff value for plantar heel pain. Results: 23 patients (age 58.0 ± 16.5 years; 13 males and 10 females) and 23 healthy participants (age 51.3 ± 17.3 years; 10 males and 13 females) formed the PHP and control groups, respectively. Peak systolic velocity on the affected side was significantly greater in the PHP group (44.1 ± 13.1 cm/s) than in the control group (32.7 ± 5.9 cm/s). No significant difference was observed between the left and right sides in the PHP (7.1 ± 9.8 cm/s) and control (3.7 ± 3.0 cm/s) groups. A cutoff value of 38.2 cm/s was observed on the affected side. Conclusions: We quantified the increase in posterior tibial artery blood flow velocity in patients with plantar heel pain. Peak systolic velocity measurements can aid in quantitatively evaluating these patients. This study was registered as a clinical trial (UMIN000046875) on 1 October 2021.

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.

Transarterial microembolization for the management of refractory chronic joint pain in osteoarthritis

Osteoarthritis (OA) is a chronic degenerative disease significantly impacting both patient quality of life and socioeconomics. Traditional treatment options, including pharmacological and surgical interventions, are often limited. Advancements in our understanding of the pathological mechanisms behind OA indicate the involvement of pathological angiogenesis. Transarterial microembolization (TAME), a minimally invasive radiological procedure, may present an innovative therapeutic approach. This review aims to consolidate current knowledge and experiences regarding TAME as a therapeutic modality for alleviating chronic joint pain associated with OA. It explores the role of TAME, focusing on its indications, patient selection, clinical outcomes, and future perspectives. Potential complications and associated risks are systematically addressed, alongside proposed strategies for risk mitigation and effective management.The presented patient cases originate from our institution, supplemented by a thorough review of relevant literature retrieved from PubMed.TAME represents a promising therapeutic approach, providing relief from the burden of joint diseases and substantially enhancing patient quality of life. Clinical outcomes emphasize the efficacy and safety of TAME in mitigating pain and improving functional capabilities in patients with chronic joint pain associated with OA. With mounting evidence of its therapeutic benefits and applicability to numerous joint-related pathologies, TAME offers a valuable addition to the arsenal of treatments for these conditions. · TAME is an innovative therapy for treating chronic joint pain related to OA.. · TAME is a technically challenging minimally invasive intervention requiring a high level of expertise.. · Understanding the challenges and complications of TAME can reduce risk and enhance procedural outcomes.. · Wilms LM, Jannusch K, Weiss D et al. Transarterial microembolization for the management of refractory chronic joint pain in osteoarthritis. Fortschr Röntgenstr 2024; DOI 10.1055/a-2288-5743.

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.

Genicular Artery Embolization: A Review of Essential Anatomic Considerations

Genicular artery embolization is increasingly recognized as a safe and effective treatment option for symptomatic knee osteoarthritis and recurrent hemarthrosis after total knee arthroplasty. Genicular arteries are an essential contributor to vascular supply for the knee joint and demonstrate considerable variability. Familiarity with the anatomy and common variations is critical for preprocedural planning, accurate target selection, and minimizing adverse events in transarterial embolization procedures. This review aimed to provide a detailed discussion of the genicular artery anatomy that is relevant to interventional radiologists performing genicular artery embolization.

Transarterial Embolization for Adhesive Capsulitis of the Shoulder: Midterm Outcomes on Function and Pain Relief

PURPOSE

To determine the safety and potential effectiveness of transarterial embolization for adhesive capsulitis of the shoulder.

MATERIALS AND METHODS

This prospective study analyzed consecutive adult patients with adhesive capsulitis referred for embolization between January 2018 and May 2023 after a poor response to treatment (symptoms and limitation of motion in ≥2 axes; ≤120° flexion, ≤50° external rotation and/or internal rotation with the shoulder abducted 90°) persisting for >3 months after having completed ≥6 weeks of analgesics and physical therapy. Different types of pain and mobility were measured before embolization and 1, 3, and 6 months after embolization. Overall upper limb function (Quick Disabilities of Arm, Shoulder, and Hand) and patient satisfaction were measured before and 6 months after embolization. Long-term follow-up comprised telephone interviews and clinical history reviews.

RESULTS

A total of 20 patients (12 [60%] women; median age, 50.7; interquartile ranges [IQR], 45‒55 years) were included; 6 (30%) had diabetes and 15 (75%) were off work. Median duration of symptoms before embolization was 39.4 weeks (IQR, 28‒49 weeks), and median duration of rehabilitation therapy was 12.8 weeks (IQR, 8‒16 weeks). Six months after embolization, significant improvements were observed in nocturnal pain (P = .003), pain on moving (P = .001), external rotation (P < .001), internal rotation (P < .001), active flexion (P < .001), passive flexion (P = .03), active abduction (P < .001), passive abduction (P < .001), and overall function (P < .001). Despite objective improvements, patient satisfaction was nearly unchanged. Only 1 patient experienced a mild adverse event.

CONCLUSION

Transarterial embolization is safe and potentially effective in treating adhesive capsulitis of the shoulder refractory to conventional treatment. Clinical improvements were maintained in the mid to long term.

In vitro study of the embolic characteristics of imipenem/cilastatin particles

BACKGROUND

Imipenem/cilastatin (IPM/CS) has long been administered intravenously as a carbapenem antibiotic. However, since this agent is poorly soluble in liquid, occasional reports have described its use as a short-acting, temporary embolic agent. The purpose of this study was to elucidate the characteristics of IPM/CS particles, which are thought to have pain-relieving effects against osteoarthritis-related pain, as an embolic agent.

METHODS

Three aspects of IPM/CS as an embolic agent were evaluated in vitro: particle size; particle shape; and change in particle size over time. For particle size, the long diameter was measured.

RESULTS

Mean particle size (n=244) was 29.2±12.0 µm (range, 1-60 µm). Shape (n=109) was round in 18.35%, elliptical in 11.93%, and polygonal in 69.72%, showing that most particles were polygonal. In observations of changes in particle size over time (n=9), particles had decreased to 75% of their original size at 82±10.7 min, 50% at 89.3±9.14 min, 25% at 91.3±8.74 min, complete dissolved at 91.8±9.02 min. A rapid shrinkage in diameter was seen in the final period.

CONCLUSIONS

IPM/CS particles are ultrafine and the majority display a polygonal shape. This substance shows ultra-short embolic activity. This study revealed the characteristics of a substance that demonstrates an embolic effect not found in existing embolic materials.

Safety and Efficacy of Genicular Artery Embolization for the Treatment of Knee Pain Secondary to Osteoarthritis-Initial Indian Experience

Background  Osteoarthritis (OA) is the commonest form of arthritis with pain and disability as hallmark symptoms. Despite various nonpharmacologic, pharmacologic, and surgical approaches, pain control may be hard to achieve. Over the last few years, few studies have been conducted on managing knee OA using novel endovascular genicular artery embolization (GAE) with varied outcomes. No such study has been reported in India yet to the best of our knowledge. Purpose  The main aim of this article was to evaluate the efficacy and safety of transcatheter GAE in relieving knee pain in patients with mild-to-moderate OA. Materials and Methods  Ten patients with radiographic knee OA and moderate-to-severe pain refractory to conservative therapy were enrolled in a prospective observational study. GAE was performed with 100 to 300-μm spherical particles. Patients were assessed with magnetic resonance imaging at the baseline. Visual analog scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were used to assess pain and disability respectively at the baseline, 1 month, and 3 months. Clinical success was asserted by the downstaging of VAS and WOMAC scores. Adverse events were recorded at all-time points. Descriptive and inferential statistics have been performed using SPSS. A p -Value less than 0.05 was considered statistically significant. Results  Embolization of at least 1 genicular artery was achieved in all the patients (100%). Clinical success was demonstrated in 08 (80%) of the patients. Median VAS reduced from 07 at baseline to 3.5 at 3-month follow-up ( p  < 0.001). Median WOMAC score improved from 53 to 23.50 at 3-month follow-up ( p  < 0.001). Minor complications were seen in two patients in the form of puncture site hematoma and mild petechial spots over the knee. Conclusion  Our pilot study demonstrates GAE as a safe and efficacious procedure to treat knee pain secondary to OA. Further randomized comparative studies with a larger sample size are needed to determine the true treatment effect versus the placebo effect.

Genicular Artery Embolization for Treatment of Knee Osteoarthritis: Interim Analysis of a Prospective Pilot Trial Including Effect on Serum Osteoarthritis-Associated Biomarkers

PURPOSE

To characterize the safety, efficacy, and potential role of genicular artery embolization (GAE) as a disease-modifying treatment for symptomatic knee osteoarthritis (OA).

MATERIALS AND METHODS

This is an interim analysis of a prospective, single-arm clinical trial of patients with symptomatic knee OA who failed conservative therapy for greater than 3 months. Sixteen patients who underwent GAE using 250-μm microspheres and had at least 1 month of follow-up were included. Six patients completed the 12-month follow-up, and 10 patients remain enrolled. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was evaluated at baseline and at 1, 3, and 12 months. Serum and plasma samples were collected for biomarker analysis. The primary end point was the percentage of patients who achieved the minimal clinically important difference (MCID) for WOMAC pain score at 12 months. Baseline and follow-up outcomes were analyzed using the Wilcoxon matched-pairs signed-rank test.

RESULTS

Technical success of the procedure was 100%, with no major adverse events. The MCID was achieved in 5 of the 6 (83%) patients at 12 months. The mean WOMAC pain score decreased from 8.6 ± 2.7 at baseline to 4.9 ± 2.7 (P = .001), 4.4 ± 2.8 (P < .001), and 4.7 ± 2.7 (P = .094) at 1, 3, and 12 months, respectively. There was a statistically significant decrease in nerve growth factor (NGF) levels at 12 months. The remaining 8 biomarkers showed no significant change at 12 months.

CONCLUSIONS

GAE is a safe and efficacious treatment for symptomatic knee OA. Decreased NGF levels after GAE may contribute to pain reduction and slowing of cartilage degeneration.

Quantifying Change in Perfusion after Genicular Artery Embolization with Parametric Analysis of Intraprocedural Digital Subtraction Angiograms

PURPOSE

To quantify perfusion changes during genicular artery embolization (GAE) with the qualitatively described "pruning" technique using parametric analysis.

MATERIALS AND METHODS

A total of 12 patients underwent unilateral GAE with a total of 36 vessels embolized. Among 34 of the 36 vessels embolized, regions of interest (ROIs) were placed on parent vessels (PVs) and hyperemic target vessels (TVs) before and after GAE. For each ROI, peak intensity (PI), time to arrival (TTA), and area under the curve (AUC) were computed and compared between PV and TV. Volume of embolic administered was correlated with adverse events.

RESULTS

No change was seen in PI, TTA, and AUC in the PV after GAE. Reduction in AUC (1,495.7 ± 521.5 vs 1,667.4 ± 574.0; P << .01) and PI (195.1 ± 43.8 vs 224.3 ± 49.2; P << .01) with increase in TTA (3.42 s ± 1.70 vs 1.92 s ± 1.45; P << .01) within the TV were observed after GAE. Median follow-up time was 89 days (range, 21-254 days). Reduction in clinical symptoms was also noted based on the Western-Ontario and McMaster Universities Arthritis Index total and pain scale at 1 month (total, 42.9% ± 23.0; pain, 54.4% ± 9.8; P << .01) and 3 months (total, 42.5% ± 14.9; pain, 57.8% ± 10.6; P << .01). Eight total mild adverse events (minor/self-limiting) were noted per Society of Interventional Radiology guidelines. A larger volume of embolic was observed in knees with skin changes (3.4 mL ± 0.4 vs 1.7 mL ± 0.4; P << .001). Furthermore, all skin changes were seen with embolic volumes >3.0 mL.

CONCLUSIONS

Quantification of intraprocedural perfusion changes with GAE demonstrated reduced flow to the TV with maintained flow in the PV and acceptable clinical outcomes. A potential relationship between embolic volume and nontarget embolization was also highlighted.

Added Value of Cone-Beam CT to Identify Arterial Supply during Genicular Artery Embolization for Knee Osteoarthritis

PURPOSE

To evaluate if the addition of cone-beam computed tomography (CT) to digital subtraction angiography (DSA) improves the identification of the genicular arteries during genicular artery embolization (GAE) for knee pain secondary to osteoarthritis (OA).

MATERIALS AND METHODS

This single-center study retrospectively analyzed 222 patients who underwent GAE for painful knee OA between May 2018 and April 2022. Intraprocedural cone-beam CT and DSA images were reviewed independently by 2 sets of interventional radiologists. DSA was performed for all patients. Technically adequate cone-beam CT was available for 205 patients (92.3%). The presence of the genicular arteries identified by cone-beam CT and DSA was compared using Φ coefficients. Embolization targets identified by both cone-beam CT and DSA were evaluated against those identified by DSA alone.

RESULTS

Genicular arteries with the highest concordance between cone-beam CT and DSA were the inferior lateral (196 vs 198; Φ = 0.3530; P < .0001), superior lateral (197 vs 200; Φ = 0.3060; P < .0001), and superior medial genicular (186 vs 161; Φ = 0.2836; P < .0001) arteries. Cone-beam CT demonstrated higher rates of detection of the inferior medial (195 vs 178; Φ = 0.04573; P = .5150) and median genicular arteries (200 vs 192; Φ = 0.04573; P = .5150). Meanwhile, genicular arteries less frequently identified by cone-beam CT were the descending genicular (197 vs 200; Φ = -0.03186; P = .6502), superior patellar (175 vs 184; Φ = 0.1332; P = .0569), and recurrent anterior tibial (156 vs 186; Φ = 0.01809; P = .7969) arteries. Cone-beam CT in combination with DSA identified 13.4% (372 vs 328) more targets compared to DSA alone.

CONCLUSIONS

Based on the results of the current study, cone-beam CT serves as a valuable adjunct for visualizing the genicular arteries during GAE, and together with DSA, it identifies more potential embolization targets.

Musculoskeletal Embolotherapy

Painful articular musculoskeletal (MSK) conditions are common, debilitating and sometimes difficult to treat. Transcatheter embolisation may offer an alternative way to manage the pain associated with these conditions, but the field is still in its infancy. To date, the most commonly studied indication is knee osteoarthritis, but the technique has been trailed in multiple other tissue beds, including for adhesive capsulitis and tendinopathies. Whilst early results appear promising, the existing studies are mostly open-labelled and non-randomised; there is a need for high-quality evidence to robustly assess the procedures efficacy. In this review, we set out to evaluate the current evidence underlying the pathophysiology and mechanism of action of embolisation; discuss the technical aspects of the procedure including embolic selection, and appraise the published clinical outcomes and adverse effects. Finally, we discuss the future directions and research priorities in this rapidly developing field.

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.

Intra-Arterial Injection of Temporary Embolic Material Through a Needle Inserted into the Radial or Ulnar Artery for Distal and Proximal Interphalangeal Joint Osteoarthritis: A Retrospective Study of 92 Patients

PURPOSE

To assess the efficacy and safety of intra-arterial injection of imipenem/cilastatin sodium (IPM/CS) via a needle placed into the radial artery or ulnar artery (RA/UA) for distal interphalangeal and proximal interphalangeal joint osteoarthritis (DIP/PIP-OA).

MATERIALS AND METHODS

This is a retrospective single-arm cohort study. Ninety-two patients [92% women, mean (SD) age 55(8.3) years] with a primary DIP/PIP-OA meet the American College of Rheumatology criteria for hand osteoarthritis with pain ≥ 4 on the 0-10 numeric rating scale (NRS) were enrolled. All procedures were performed by injecting IPM/CS through a 24-gauge needle percutaneously inserted into the RA/UA. Two procedures were planned; the second procedure was scheduled 1-2 months after the first. NRS, Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score, Patient Global Impression of Change (PGIC) scale, and procedure-related adverse events were evaluated.

RESULTS

Technical success, defined as injection of IPM/CS into the RA/UA, was achieved in all patients. Clinical success, defined as a reduction of 2 points or more in the NRS at 12 months, was 77% (95% confidence interval 68-85%). The NRS improved from the baseline to 3, 6, and 12 months (7.8 ± 1.6 vs. 3.8 ± 2.6, 3.9 ± 2.7, and 4.0 ± 2.8, respectively, all p < 0.001). The QuickDASH score improved from the baseline to 12 months (27 ± 15 vs. 19 ± 17, p < 0.001) respectively. No major adverse events were observed.

CONCLUSIONS

Intra-arterial injection of IPM/CS is a feasible treatment option for DIP/PIP-OA.

Outcomes after Genicular Artery Embolization Vary According to the Radiographic Severity of Osteoarthritis: Results from a Prospective Single-Center Study

This prospective single-center study compared outcomes after genicular artery embolization (GAE) in people with mild radiographic knee osteoarthritis (OA) (n = 11) versus moderate to severe radiographic knee OA (n = 22). The mild OA group was older and had experienced symptoms for less time (P < .05). All participants underwent complete embolization of neovessels from genicular arteries. The primary outcome was the proportion of responders at 6 months according to predetermined improvements in pain, function, and/or global change. Results indicated that a higher proportion of participants (n = 9, 81.8%) with mild OA fulfilled responder criteria after treatment compared with people with moderate to severe OA (n = 8, 36.4%) (P = .014). Secondary outcomes for pain, quality of life, and global change were also better in the mild OA group (P < .05). No serious adverse events occurred, including the absence of osteonecrosis on magnetic resonance imaging. The study demonstrated that outcomes after GAE varied according to the severity of baseline radiographic OA.

Genicular Artery Embolisation in Patients with Osteoarthritis of the Knee (GENESIS 2): Protocol for a Double-Blind Randomised Sham-Controlled Trial

Knee osteoarthritis is a leading cause of chronic disability and economic burden. In many patients who are not surgical candidates, existing treatment options are insufficient. Clinical evidence for a new treatment approach, genicular artery embolisation (GAE), is currently limited to single arm cohort, or small population randomised studies. This trial will investigate the use of a permanent embolic agent for embolisation of abnormal genicular arterial vasculature to reduce pain in patients with mild to moderate knee osteoarthritis. Up to 110 participants, 45 years or older, with knee pain for ≥ 3 months resistant to conservative treatment will be randomised (1:1) to GAE or a sham procedure. The treatment group will receive embolisation using 100-micron Embozene™ microspheres (Varian, a Siemens Healthineers Company) (investigational use for this indication in the UK), and the sham group will receive 0.9% saline in an otherwise identical procedure. Patients will be followed for 24 months. At 6 months, sham participants will be offered crossover to GAE. The primary endpoint is change of 4 Knee Injury and OA Outcome Score subscales (KOOS4) at 6 months post-randomisation. The study will also evaluate quality of life, health economics, imaging findings, and psychosocial pain outcomes. The primary manuscript will be submitted for publication after all participants complete 6 months of follow-up. The trial is expected to run for 3.5 years. Trial Registration: ClinicalTrials.gov, Identifier: NCT05423587.

Effectiveness and Safety of Intra-arterial Imipenem/Cilastatin Sodium Infusion for Patients with Hand Osteoarthritis-Related Interphalangeal Joint Pain

PURPOSE

To evaluate the effectiveness and safety of intra-arterial imipenem/cilastatin sodium (IPM/CS) infusion for painful interphalangeal joint osteoarthritis (OA).

MATERIALS AND METHODS

Fifty-eight patients with interphalangeal joint OA who underwent intra-arterial IPM/CS infusion were retrospectively evaluated. Intra-arterial infusions were performed via percutaneous wrist arterial access. The Numerical Rating Scale (NRS), Functional Index for Hand Osteoarthritis (FIHOA), and Patient Global Impression of Change (PGIC) scale scores were assessed at intervals of 1, 3, 6, 12, and 18 months. Clinical success was evaluated based on PGIC.

RESULTS

All patients were followed up for at least 6 months after treatment. Of them, 30 and 6 patients were followed up for 12 and 18 months, respectively. No severe or life-threatening adverse events were encountered. The mean NRS score was 6.0 ± 1.4 at baseline, which significantly decreased to 2.8 ± 1.4, 2.2 ± 1.9, and 2.4 ± 1.9 at 1, 3, and 6 months after treatment, respectively (all P < .001). The mean NRS scores were 2.8 ± 1.7 and 2.9 ± 1.9 at 12 and 18 months, respectively, in the remaining patients. The mean FIHOA score significantly decreased from 9.8 ± 5.0 at the baseline to 4.1 ± 3.5 at 3 months (P < .001). The mean FIHOA score was 4.5 ± 3.3 at 12 months in the remaining 30 patients. The clinical success rates based on PGIC at 1, 3, 6, 12, and 18 months were 62.1%, 77.6%, 70.7%, 63.4%, and 50.0%, respectively.

CONCLUSIONS

Intra-arterial IPM/CS infusion is a potential treatment option for interphalangeal joint OA refractory to medical management.

Transcatheter embolisation in chronic musculoskeletal disorders

Chronic musculoskeletal conditions affect millions of patients worldwide resulting in disability, reduced quality of life, and have a profound economic impact on the individual and society. Current treatment strategies fail patients who have not responded to conservative management but are not surgical candidates. Over the last decade, transcatheter embolisation has emerged as a potential treatment for these difficult to treat patients. By exploiting pathological neovascularisation within conditions such as knee osteoarthritis, adhesive capsulitis, and tendinopathy, embolisation has been used to improve patients' pain and function. This review explores the rationale for musculoskeletal transcatheter embolisation, illustrating the technique, and latest evidence for the most common procedures.

Genicular Artery Embolization for Knee Osteoarthritis: A Comprehensive Review

» Genicular artery embolization (GAE) is a promising treatment option for patients with knee osteoarthritis who are unresponsive to nonsurgical treatments and not yet candidates for surgery.» Current evidence supports the effectiveness of GAE in reducing pain and synovitis, with few reported major adverse events.» The cost-effectiveness and long-term results of GAE compared with other treatment options require further investigation.» Limitations of existing studies include small sample sizes, single-center trials, and lack of comparison between embolic agents and other treatments.» Future research should focus on larger, multicenter trials with longer follow-up periods and head-to-head comparisons with alternative treatment modalities to establish the role of GAE in the management of knee osteoarthritis.

Short-Term Effects of Genicular Artery Embolization on Symptoms and Bone Marrow Abnormalities in Patients with Refractory Knee Osteoarthritis

PURPOSE

To evaluate the short-term outcomes of genicular artery embolization (GAE) for knee osteoarthritis (OA) with and without bone marrow lesion (BML) and/or subchondral insufficiency fracture of the knee (SIFK).

MATERIALS AND METHODS

This single-institution prospective observational pilot study analyzed 24 knees in 22 patients with mild to moderate knee OA, including 8 knees without BML, 13 knees with BML, and 3 knees with both BML and SIFK. The area and volume of BMLs on magnetic resonance images were measured before and after GAE. Baseline and postoperative pain and physical function were assessed using the visual analog scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

RESULTS

GAE significantly reduced the BML area and volume 3 months after embolization in the knees with BML (both P < .0005). GAE significantly decreased the VAS scores at 3 and 6 months after embolization in patients without BML (both P = .04) and those with BML (both P = .01). GAE also lowered the WOMAC scores 3 months after embolization in patients without and with BML (P = .02 and P = .0002, respectively). However, GAE did not significantly alter the BML area and volume (both P = .25), VAS scores (P = 1.00), and WOMAC scores (P = .08) in patients with BML and SIFK at 3 months after GAE.

CONCLUSIONS

This observational pilot study suggested that GAE effectively reduces the BML area and volume and improves pain and physical function in patients with knee OA accompanied by BML but is inefficacious in those with both BML and SIFK.

Joint interventions in osteoarthritis

Osteoarthritis (OA) is among the most common diseases affecting both axial and appendicular joints and the lead cause of disability worldwide. OA incidence is rising due to extended life expectancy and the increasing obesity epidemic. Several joint interventions are available to manage pain and joint function in patients with OA, most of these treatments being widely applied using intra-articular injections. In this chapter, we will describe the different joint interventions available for the management of pain in OA focusing on intra-articular injections, including discussion on the evidence regarding the efficacy of these treatments, based on the most recent systematic reviews and meta-analyses available. We also discuss the importance of imaging in guiding these treatments, including the different imaging modalities available for intra-articular injection guidance, their advantages, and disadvantages. Finally, we briefly discuss safety data and the consensus regarding the most used intra-articular treatments to manage pain in OA.

The short-to-midterm outcomes of geniculate artery embolization for mild-to-moderate osteoarthritis of the knee: a systematic review

Background

Geniculate Artery Embolization (GAE) is a novel, minimally-invasive treatment for mild to moderate Osteoarthritis (OA) associated with musculoskeletal pain.

Purpose

To investigate the outcomes of GAE in patients with mild to moderate OA of the knee using a Quantitative-analysis of the available literature.

Methods

The PubMed, EMBASE and Cochrane databases were searched for GAE-related studies. Qualitative and quantitative analyses were performed following PRISMA-guidelines. Quantitative-analysis was performed using windows based 'MedCalc-Statistical-Software version 19.6.1 (2020). Statistical analysis was performed in Stata-IC-13.1(Stata corp-USA). Quantitative-analysis was done using the random-effects model, and the Standardized-Mean-Differences (SMD) were calculated.

Results

After a full-text review, 13 studies with 399 knees (345-patients) were included in the qualitative synthesis, 10 were included in the quantitative synthesis. The total WOMAC score improved by a [SMD (95% CI)] of 3.46 points (1.27, 5.65), 3.50 (1.28, 5.71), 3.77 (0.58, 6.96), 5.46 (1.59, 9.33), 2.96 (-0.93, 6.85) compared to baseline at 1, 3, 6, 12, 24 months respectively. The VAS score improved by 2.06 (1.35, 2.76), 2.13 (1.39, 2.87), 2.36 (1.85, 2.90), 2.09 (0.91, 3.28) compared to baseline at 1, 3, 6, 12 months respectively. The Pain WOMAC score improved by SMD 2.97 (0.51, 5.43), 3.77 (0.58, 6.96), 2.27 (0.31, 4.22), 2.27 (0.31, 4.22) compared to baseline at 1, 3, 12, 24 months, respectively.

Conclusion

There was a statistically significant change from baseline in all outcome measures after GAE. GAE is a safe and effective method for pain control in mild to moderate OA-associated knee pain in the short and medium term.

Genicular Artery Embolization as a Treatment for Osteoarthritis Related Knee Pain: A Systematic Review and Meta-analysis

OBJECTIVE

Genicular artery embolization (GAE) is a minimally invasive therapy for symptomatic osteoarthritis (OA) in patients with knee pain refractory to conservative management. The purpose of this study was to evaluate evidence on the effectiveness of GAE for OA related knee pain as part of a systematic review and meta-analysis.

MATERIALS AND METHODS

Using Embase, PubMed, and Web of Science, a systematic review was performed to identify studies evaluating treatment of knee OA with GAE. The primary outcome measure was change in pain scale score at 6 months. A Hedge's g was computed as a measure of effect size, selecting Visual Analog Scale (VAS) first if available and Knee Injury and Osteoarthritis Outcome Score and Western Ontario and McMaster Universities Osteoarthritis Index if VAS was not available.

RESULTS

After screening titles, abstracts, and the full text, 10 studies met inclusion criteria. A total of 351 treated knees were included. Patients who underwent GAE demonstrated declines in VAS pain scores at 1 month {- 34 points [95% CI (- 43.8, - 24.6)], 3 months {- 30 points [95% CI (- 41.7, - 19.2)], 6 months {- 41 points [95% CI (- 54.0, - 27.2)], and 12 months {- 37 points [95% CI (- 55.0, - 18.1)]. Hedges' g from baseline to 1, 3, 6, and 12 months, was {- 1.3 [95% CI (- 1.6, - 0.97)]}, {- 1.2 [95% CI (- 1.54, - 0.84)]}, {- 1.4 [95% CI (- 2.1, - 0.8)]}, and {- 1.25 [95% CI (- 2.0, - 0.6)]}, respectively.

CONCLUSION

GAE provides durable reductions in pain scores for patients suffering with mild, moderate, and severe OA.

Genicular artery embolization for early-stage knee osteoarthritis: results from a triple-blind single-centre randomized controlled trial

This study investigated the effects of transcatheter arterial embolization (TAE) on pain, function, and quality of life in people with early-stage symptomatic knee osteoarthritis (OA) compared to a sham procedure. A total of 59 participants with symptomatic Kellgren-Lawrence grade 2 knee OA were randomly allocated to TAE or a sham procedure. The intervention group underwent TAE of one or more genicular arteries. The control group received a blinded sham procedure. The primary outcome was knee pain at 12 months according to the Knee injury and Osteoarthritis Outcome Score (KOOS) pain scale. Secondary outcomes included self-reported function and quality of life (KOOS, EuroQol five-dimension five-level questionnaire (EQ-5D-5L)), self-reported Global Change, six-minute walk test, 30-second chair stand test, and adverse events. Subgroup analyses compared participants who received complete embolization of all genicular arteries (as distinct from embolization of some arteries) (n = 17) with the control group (n = 29) for KOOS and Global Change scores at 12 months. Continuous variables were analyzed with quantile regression, adjusting for baseline scores. Dichotomized variables were analyzed with chi-squared tests. Overall, 58 participants provided questionnaire data at 12 months. No significant differences were found for the primary and secondary outcomes, with both groups improving following the procedure. At 12 months, KOOS pain scores improved by 41.3% and 29.4% in the intervention and control groups, respectively. No adverse events occurred. Subgroup analysis indicated that the complete embolization group had significantly better KOOS Sports and Recreation, KOOS Quality of Life, and Global Change scores than the control group; 76.5% of participants who received complete embolization reporting being moderately or much better compared to 37.9% of the control group. TAE might produce benefits above placebo, but only when complete embolization of all genicular arteries is performed. Further comparative studies are required before definitive conclusions regarding the effectiveness of TAE can be made. Level of evidence: I.

Biomarkers of Osteoarthritis—A Narrative Review on Causal Links with Metabolic Syndrome

Development of OA (OA) is multifactorial and is strongly associated with risk factors such as aging, trauma, metabolic disorders, and obesity. Metabolic Syndrome (MetS)-associated OA, collectively coined MetS-OA, is an increasingly recognized entity in which metabolic disorders and low-grade inflammation play a key mechanistic role in the disruption of joint homeostasis and cartilage degradation. Although there have been enormous efforts to discover biomarkers of MetS and OA, studies investigating a pathophysiological link between MetS and OA are relatively limited, and no serum blood marker has proved diagnostic so far. OA biomarkers that are necessary to discriminate and diagnose early disease remain to be elicited, explained in part by limited prospective studies, and therefore limited tools available to utilize in any prognostic capacity. Biomarker validation projects have been established by the Biomarker Consortium to determine biochemical markers demonstrating predictive validity for knee OA. Given that the metabolic constituents of MetS are treatable to varying extents, it stands to reason that treating these, and monitoring such treatment, may help to mitigate deleterious links with OA development. This narrative review will describe the current state of biomarker identification and utility in OA associated with MetS. We discuss the pathophysiological mechanisms of disease according to constituent pathologies of MetS and how identification of biomarkers may guide future investigation of novel targets.

Genicular Artery Embolization Technique

Genicular artery embolization (GAE) is a safe and effective treatment for knee pain related to osteoarthritis, however there are several aspects of the procedure technique which may be unique. Familiarity with procedural steps, arterial anatomy, embolic endpoints, technical challenges, and potential complications is imperative for good clinical practice and outcomes. The success of GAE depends on correctly interpreting angiographic findings and variable anatomy, navigating small and acutely angled arteries, recognizing collateral supply, and avoiding non-target embolization. The procedure can potentially be performed for a wide range of patients with knee osteoarthritis. When effective, pain relief can be durable for many years. When done meticulously, adverse events from GAE are uncommon.

Genicular Artery Embolization Data Review

Osteoarthritis of the knee poses an ever-expanding healthcare challenge worldwide. Current treatments include conservative methods such as weight loss, pharmacological treatments including NSAIDs, and surgical techniques including total knee arthroplasty. Although frequently successful, contraindications and failure of pharmacological agents leave many, especially with mild-moderate disease, without effective treatment. Genicular artery embolization is an interventional radiology technique being developed to fill this treatment gap. For this procedure to become established, the literature must provide evidence of its underlying scientific principles, safety, efficacy and economic viability. Pathological investigation of osteoarthritis reveals that low-level inflammation plays a crucial role in disease development. Joint inflammation stimulates neoangiogenesis and accompanying neuronal growth, with the degree of microvascular invasion being correlated with more severe pain in animal models. These neovessels provide a target for embolization however, the microscopic effects of this intervention are yet to be elucidated. The side effects of GAE have been extensively investigated with no severe adverse events being recorded. Skin discoloration and puncture site hematoma are the most common, occurring in 10%-65% and 0%-17% of patients respectively. The literature also discusses ways to minimize these events. Phase one studies provide promising evidence of efficacy, demonstrating an 80% improvement in Visual Analogue Scale (VAS) and a mean difference of 36.8 in Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores at 24-months. These positive signals are also supported by a single randomized control trial. A single study has been completed regarding the cost of GAE, however further work is needed. The GAE literature demonstrates a safe procedure with promising initial evidence of efficacy. Future work should further elucidate the pathology of osteoarthritis and ways in which embolization modifies this process, alongside providing further randomized control evidence that aligns with the recommendations from the National Institute for Health and Care Excellence. The future of GAE is exciting!

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.

Role of geniculate artery embolization in the treatment of knee pain secondary to osteoarthritis

Background

Osteoarthritis (OA) is a leading cause of chronic knee pain and disability with a reported prevalence of 25–30% of the population. Knee OA has traditionally been thought as a degenerative disease only related to chronic repetitive injury “wear and tear” mechanism, yet it is now considered as a much more complex disease of inflammatory nature induced by cytokines and inflammatory mediators through abnormal neo-vascularization (angiogenesis). The rational of geniculate artery embolization (GAE) is based on the hypothesis that suggesting a direct relationship between the abnormal angiogenesis and the chronic knee pain. As a novel treatment option based on occlusion of these abnormal neo-vessels via geniculate artery embolization, we postulated that such a mechanism will relieve pain and improve the quality of life. GAE has been previously approved as a safe and effective treatment in cases of post-knee arthroplasty hemarthrosis.

Purpose

To evaluate the feasibility, safety, and efficacy of geniculate artery embolization for OA-related knee pain.

Materials and methods

Sixteen patients with knee pain secondary to chronic OA refractory to conservative therapies for at least 6 months and not yet fit for total knee replacement were enrolled in a prospective single arm interventional study. GAE was performed using 150–300 μm microspheres. Patients were assessed and followed up using the visual analogue scale (VAS) for pain and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) for the overall knee function at baseline and at 1 week, 1, 3, and 6 months post-embolization.

Results

A total 16 patients presented by knee pain secondary to chronic OA were enrolled. All of them showed a remarkable improvement in the VAS and WOMAC scores, with better clinical outcome after GAE. Pre- versus post-embolization ± MDs in VAS score from 8.38 ± 0.81 (baseline) to 2.88 ± 1.54 after 6 months (post-embolization) equivalent to 66.66% improvement. There was also a satisfactory improvement in the WOMAC scores, with ± MDs drop from 77.94 ± 10.62 (baseline) to 49.69 ± 15.43 (post-embolization) equivalent to 37.41% improvement. No severe or life-threatening complications were reported.

Conclusions

GAE holds promise as an effective minimally invasive procedure for the treatment of knee pain secondary to OA and could be introduced as a safe technique with no serious complications.

Genicular artery embolization for treatment of knee osteoarthritis pain: Systematic review and meta-analysis

Objective

Genicular artery embolization (GAE) is a novel, minimally invasive procedure for treatment of knee osteoarthritis (OA). This meta-analysis investigated the safety and effectiveness of this procedure.

Design

Outcomes of this systematic review with meta-analysis were technical success, knee pain visual analog scale (VAS; 0-100 scale), WOMAC Total Score (0-100 scale), retreatment rate, and adverse events. Continuous outcomes were calculated as the weighted mean difference (WMD) versus baseline. Minimal clinically important difference (MCID) and substantial clinical benefit (SCB) rates were estimated in Monte Carlo simulations. Rates of total knee replacement and repeat GAE were calculated using life-table methods.

Results

In 10 groups (9 studies; 270 patients; 339 knees), GAE technical success was 99.7%. Over 12 months, the WMD ranged from -34 to -39 at each follow-up for VAS score and -28 to -34 for WOMAC Total score (all p ​< ​0.001). At 12 months, 78% met the MCID for VAS score; 92% met the MCID for WOMAC Total score, and 78% met the SCB for WOMAC Total score. Higher baseline knee pain severity was associated with greater improvements in knee pain. Over 2 years, 5.2% of patients underwent total knee replacement and 8.3% received repeat GAE. Adverse events were minor, with transient skin discoloration as the most common (11.6%).

Conclusions

Limited evidence suggests that GAE is a safe procedure that confers improvement in knee OA symptoms at established MCID thresholds. Patients with greater knee pain severity may be more responsive to GAE.

Two-year outcomes comparing Embosphere® microspheres versus Imipenem Cilastatin for genicular artery embolization in patients with moderate to severe knee osteoarthritis

BACKGROUND

Genicular artery embolization (GAE) is a novel technique and has the potential to provide midterm relief of pain for patients with mild-to-moderate knee osteoarthritis resistant to conservative management. This study compares the efficacy and safety of trisacryl gelatin microspheres to Imipenem/Cilastatin particles for GAE with 2 years of clinical follow-up.

METHODS

In this retrospective study, eight patients with knee osteoarthritis (11 knees) who underwent GAE with 100-300 μm trisacryl gelatin microspheres particles were compared with six patients (nine knees) who underwent GAE with Imipenem/Cilastatin particles. Clinical outcomes were evaluated at 3-month and 24-month follow-ups and compared to baseline using the WOMAC questionnaire.

RESULTS

The median follow-up was 796 days (range: 736-808). There were no significant differences in clinical outcome measures at the 3-month or 24-month follow-up. Both embolic materials resulted in a decrease in Pain WOMAC and Total WOMAC scores at 3 months (p < 0.05), and the effect of treatment on Pain WOMAC and Total WOMAC score reduction was sustained until the 24-month follow-up (p < 0.05). Minor events (Clavien-Dindo classification grade I) included transient cutaneous color change (n = 3) and transient leg numbness (n = 1) after embolization with trisacryl gelatin microspheres particles (p = 0.08). All minor adverse events resolved spontaneously. There were no major adverse events.

CONCLUSION

One hundred to three hundred μm trisacryl gelatin microspheres particles can be considered for genicular artery embolization and is comparable to Imipenem/Cilastatin particles in pain reduction of moderate to severe knee osteoarthritis. A sustained effect is observed for up to 2 years of follow-up.