Presentations

Abstract

Introduction: Chronic knee pain is a widespread and debilitating condition that affects millions of individuals, severely impacting their ability to perform daily activities, such as walking and exercising. Beyond the physical discomfort, chronic knee pain can lead to reduced mobility, an increased risk of comorbidities, and mental health challenges, including depression and anxiety due to the diminished quality of life. Osteoarthritis is the most common cause of chronic knee pain, affecting approximately 14 million people in the United States. Traditionally, treatment has focused on nonsteroidal anti-inflammatory drugs (NSAIDs), intra-articular injections, and surgical interventions like knee arthroplasty. However, the high prevalence of chronic knee pain among older adults presents unique challenges, as many patients require less invasive options to manage their symptoms effectively. Contraindications to invasive surgical procedures, such as comorbid conditions (e.g., cardiovascular disease, diabetes), poor overall health, and the increased risk of complications from anesthesia, further necessitate the exploration of less invasive alternatives. Interventional radiology has emerged as a promising field, offering two minimally invasive techniques-Genicular Artery Embolization (GAE) and Genicular Nerve Ablation (GNA)-to alleviate chronic knee pain. These innovative approaches minimize the risks associated with traditional surgery while providing effective pain relief. GAE and GNA can serve as alternatives or adjuncts to conventional treatments, offering new hope for patients seeking to manage their pain with minimal disruption to their daily lives while avoiding potential complications.

Main Body: Genicular Artery Embolization (GAE) GAE involves the targeted embolization of the genicular arteries, which are small vessels that supply blood to the knee joint. Increased blood flow through these arteries is theorized to exacerbate pain by promoting inflammation in the affected joint and increasing migration of inflammatory cells. By embolizing, or blocking, these arteries, blood flow to the joint is reduced, leading to decreased inflammation and pain relief. The procedure is performed under fluoroscopic or CT guidance, with a catheter inserted into the femoral artery and advanced to the genicular arteries, where embolic agents are injected to selectively block blood flow. GAE provides significant and long-lasting pain relief, particularly in patients with osteoarthritis who have not responded to NSAIDs, physical therapy, or intra-articular injections. Pain relief is reported up to 24 months after the procedure, however, patients with severe osteoarthritis report the return of pain 6 months post-procedure. The efficacy of GAE has shown promise in several prospective randomized control trials. Patients were followed at intervals ranging from 3 months to 3 years post procedure. There was a statistically significant response to treatment, as measured through quality-of-life scores, physical activity tests and MRI analysis of synovial inflammation. Complications including hematomas, cutaneous ischemia, infection, and inadvertent embolization of non-target arteries are rare and mitigated by sterile techniques and precise imaging guidance. The procedure typically lasts around 60 to 90 minutes, and patients usually experience rapid recovery with minimal downtime. Genicular Nerve Ablation (GNA) GNA involves denaturing of the genicular nerves, which are sensory nerves that transmit pain signals from the knee joint to the brain. By denaturing these nerves, the transmission of pain signals is interrupted, reducing the sensation of pain in the knee. This can be achieved through various techniques, most commonly radiofrequency ablation or cryoablation. Under fluoroscopic or ultrasound guidance, a radiologist advances an electrode to the target area and delivers heat or cold to ablate the nerve, effectively cutting off its ability to transmit pain signals. GNA is commonly indicated for patients with chronic knee pain, particularly due to osteoarthritis, who have not responded adequately to conservative treatments, or who continue to experience pain after knee arthroplasty. If a nerve block successfully alleviates the patient's pain, it suggests they are a good candidate for GNA. GNA provides significant and sustained pain relief, improving both quality of life and functional ability for up to 24 months. Pain may return in time due to potential regrowth or regeneration of the geniculate nerves. GNA has been efficacious in comparison to the current standard of care, intra-articular corticosteroid injections. A multi-center randomized control trial found a statistically significant difference post treatment pain scoring, with 74% of GNA patients and 16% of corticosteroid injection patients reporting >50% reduction in pain at 6-month post-treatment. GNA is typically well tolerated, potential complications are minimal and may include temporary soreness at the treatment site, numbness or swelling in the treated area, hemarthrosis, or subcutaneous bleeding. Vascular complications are rare but possible. GNA is an outpatient procedure, allowing patients to return home the same day and typically resume normal activities shortly after.

Conclusion: Genicular Artery Embolization (GAE) and Genicular Nerve Ablation (GNA) are exciting developments in the treatment of osteoarthritis. Initial studies into the efficacy of these treatments show promise. However, there is benefit in conducting larger scale studies on their efficacy, especially in comparison to the current standards of care. There are numerous opportunities for advancements in research, technology, and clinical practice. As these techniques continue to evolve and integrate into the standard of care, there is the potential to offer more effective, personalized, and accessible treatment options for patients suffering from chronic knee pain. Through ongoing innovation and integration into multidisciplinary care models, GAE and GNA may become cornerstone treatments in the management of knee pain in the coming years.