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Knee osteoarthritis (KOA) is a common chronic degenerative osteoarthritic disease in clinical practice. Knee pain is the most important clinical manifestation of KOA, and it is also the first reason for patients to seek medical treatment. Knee pain not only restricts patients' daily life, but also negatively affects their physical and mental health, and imposes a huge economic burden on society and patients' families, so it is crucial to effectively manage pain in patients with KOA. For mild to moderate KOA, oral nonsteroidal anti-inflammatory drugs (NSAIDs), dextrose, and intra-articular injection of sodium hyaluronate are commonly used in clinical practice [1].

However, long-term oral NSAIDs have poor clinical efficacy and are prone to complications such as gastrointestinal adverse effects and renal damage. Oral glucosamine and intra-articular injection of sodium vitrate can relieve the symptoms to a certain extent, but with limited effect . Knee arthroplasty is a very effective treatment for end-stage KOA, but it is not suitable for mild-to-moderate KOA and younger patients, so new treatment ideas and methods for pain management in these patients need to be found [2]. Okuno et al[3] first reported the use of transcatheter arterial embolization (TAE) to selectively embolize the knee artery in the treatment of mild-to-moderate KOA, and achieved satisfactory clinical efficacy, which was referred to as genicular artery embolization (GAE).

The purpose of GAE in the treatment of KOA is not to block blood flow, but to precisely embolize the local abnormally proliferated blood vessels while maintaining the blood supply to the bones and muscles in order to reduce the local inflammatory response. The target of embolization is the proliferated small blood vessels around the target vessels. Therefore, GAE is a kind of “pruning” rather than “blocking”, and the target vessels for GAE include the descending knee artery, upper and lower medial knee arteries, upper and lower lateral knee arteries, median knee artery, and anterior tibial circumflex artery[4]. GAE involves ultrasound-guided arterial access and selective arterial angiography to confirm that the target vessel is consistent with the location of the pain, and then an embolic agent is injected to embolize the abnormally proliferating vessel at the site of the pain.

The indications for the use of GAE in the treatment of KOA include: osteoarthritis with Kellgren-Lawrence imaging grade I,II,III, with poor non-surgical treatment and with knee pain visual analogue scale (VAS) score more than 5. Contraindications include: osteoarthritis with Kellgren-Lawrence imaging grade IV, combined with soft tissue injury around the knee joint, with localized infection of the knee joint, with atherosclerosis, with allergy to contrast agents and embolic agents. Okuno et al [3] reported that 14 patients with mild-to-moderate KOA were treated with GAE, and the follow-up results showed that the Western Ontario and McMaster University os-teoarthritis index (WOMAC) score decreased from the preoperative (12.2 ± 1.9) to the postoperative (3.3 ± 2.1) at 1 month and 4 months after surgery and proved for the first time that GAE is safe and effective. In another study[5], some patients with mild-to-moderate KOA treated with GAE experienced recurrence after pain relief, and the clinical success rate of patients with moderate KOA was slightly lower than that of patients with mild KOA. This suggests that the efficacy of GAE is different for patients with different degrees of KOA.

Reference:

  1. Guede-Rojas F, Benavides-Villanueva A, Salgado-González S, Mendoza C, Arias-Álvarez G, Soto-Martínez A, Carvajal-Parodi C. Effect of strength training on knee proprioception in patients with knee osteoarthritis: A systematic review and meta-analysis. Sports Med Health Sci. 2023 Nov 7;6(2):101-110.

  2. Martin-Vega FJ, Lucena-Anton D, Galán-Mercant A, Perez-Cabezas V, Luque-Moreno C, Vinolo-Gil MJ, Gonzalez-Medina G. Phonophoresis through Nonsteroidal Anti-Inflammatory Drugs for Knee Osteoarthritis Treatment: Systematic Review and Meta-Analysis. Biomedicines. 2022 Dec 14;10(12):3254.

  3. Okuno Y, Korchi AM, Shinjo T, Kato S. Transcatheter arterial embolization as a treatment for medial knee pain in patients with mild to moderate osteoarthritis. Cardiovasc Intervent Radiol. 2015 Apr;38(2):336-43.

  4. Iwamoto W, Okuno Y, Matsumura N, Kaneko T, Ikegami H. Transcatheter arterial embolization of abnormal vessels as a treatment for lateral epicondylitis refractory to conservative treatment: a pilot study with a 2-year follow-up. J Shoulder Elbow Surg. 2017 Aug;26(8):1335-1341.

  5. Okuno Y, Korchi AM, Shinjo T, Kato S, Kaneko T. Midterm Clinical Outcomes and MR Imaging Changes after Transcatheter Arterial Embolization as a Treatment for Mild to Moderate Radiographic Knee Osteoarthritis Resistant to Conservative Treatment. J Vasc Interv Radiol. 2017 Jul;28(7):995-1002.