Knee osteoarthritis
The patient profile the published GAE studies actually enrolled, the reasons we would not recommend it, and an honest summary of the mixed evidence for Los Angeles and Orange County patients.
Editorially updated October 19, 2026. This educational article was prepared by SoCal Interventional using the cited primary and authoritative sources. It does not replace an individualized medical evaluation.
Quick answer: Genicular artery embolization (GAE) has been studied mainly in adults with mild to moderate knee osteoarthritis (Kellgren–Lawrence grade 1 to 3 on X-ray) whose knee pain has lasted at least three to six months despite exercise therapy, weight management, medication or injections. It is generally not offered for bone-on-bone (grade 4) arthritis, inflammatory or infected joints, a knee that has already been replaced, an uncorrectable bleeding disorder or significantly reduced kidney function. Being a candidate is not the same as being likely to benefit: uncontrolled studies are encouraging, but the blinded sham-controlled trials so far are mixed. The rest of this article walks through each criterion and where it comes from.
Patients in Orange County are evaluated at our Fountain Valley office; patients in the San Fernando Valley and Los Angeles are seen in Van Nuys and Tarzana. Call (310) 929-0026 or request a consultation. GAE is offered at our Fountain Valley office in Orange County as well as in Los Angeles and Tarzana.
Candidacy matters more for GAE because the procedure treats inflammation in the joint lining, not the arthritis itself: it does not rebuild cartilage, straighten the knee or fix a torn meniscus. The patients most likely to benefit are those whose pain comes mainly from synovial inflammation in a knee that still has joint space, not a structurally worn-out knee.
GAE blocks small, abnormal blood vessels that grow into the inflamed lining of an arthritic knee (the synovium). The idea is to reduce the inflammation and nerve signals that drive pain. It does not rebuild cartilage, straighten a knee or fix a torn meniscus. In the GENESIS study, MRI one year after embolization still showed cartilage loss and osteophytes progressing, even in patients whose pain improved. That is why the best-studied candidates are people whose pain seems to come mainly from inflammation in a knee that still has some joint space left, not people whose knee is structurally worn out.
The criteria the GAE studies used are a Kellgren–Lawrence grade of 1 to 3 on a standing X-ray, knee pain for at least three to six months despite conservative care, adult age (typically 45 to 80 in practice), adequate kidney function, and no rheumatoid or infected arthritis, prior knee replacement or uncorrectable bleeding disorder. The table shows where each criterion comes from.
| Factor | What the studies enrolled | How we use it at consultation |
|---|---|---|
| X-ray grade (Kellgren–Lawrence) | GENESIS: grade 1–3, grade 4 excluded (median grade 3). Australian sham trial: grade 2 only. | We review a recent standing knee X-ray. Grade 4 is usually referred for an orthopedic opinion first. |
| Duration of pain | GENESIS: more than 6 months despite conservative care. Sham trial: at least 6 months. NYU trial (2025): more than 3 months. | Pain lasting several months despite a fair trial of non-surgical care. |
| Age | GENESIS: 45 and older (treated ages 45–83). Sham trial: 18–75. | No hard cutoff; our screening checklist uses 45 to 80 as the typical range. |
| Body weight | GENESIS had no BMI limit (median BMI 30, range 20–48). | Higher weight does not by itself rule GAE out; weight management stays part of the plan. |
| Prior treatment | Conservative management first; many participants were using paracetamol, anti-inflammatories or opioids. | Physical therapy, medication and injections are usually tried first. |
| Kidney function | GENESIS excluded eGFR below 45. | Blood work before the procedure because the angiogram uses contrast dye. |
| Other exclusions | GENESIS: rheumatoid or infectious arthritis, previous knee replacement, uncorrectable bleeding disorder. | We also screen for active infection and severe arterial disease in the leg. |
Sources: GENESIS long-term results (CardioVascular and Interventional Radiology, 2024); Landers et al., Bone & Joint Open 2023; Taslakian et al., J Vasc Interv Radiol 2025. Full references below.
Grade 4 (bone-on-bone) arthritis is usually a different conversation because every GAE study cited here excluded it, so there is almost no evidence on how embolization performs in advanced arthritis. For bone-on-bone knees, knee replacement remains the standard option to discuss first; GAE is studied in grades 1 to 3.
The Kellgren–Lawrence scale grades knee X-rays from 0 (normal) to 4 (severe narrowing with bone-on-bone contact, large bone spurs and deformity). Grades 1 to 3 describe early to moderate arthritis. The GAE studies cited on this page all excluded grade 4, so there is very little evidence about how it performs in advanced arthritis. An independent 2023 health technology assessment from the Canary Islands Health Service found no evidence on GAE for severe osteoarthritis in people who are not surgical candidates. For bone-on-bone knees, knee replacement remains the standard to discuss; see our comparison of GAE vs injections vs knee replacement.
Prior cortisone or gel injections do not rule GAE out; most study patients had them. A shot that helped for a few weeks and then wore off points to the inflamed joint lining that GAE targets; one that never helped points elsewhere, such as a mechanical problem, the hip or the spine. We ask for a four-to-six-week gap after the last steroid injection.
Most patients who ask about GAE have already had cortisone and sometimes gel (hyaluronic acid) injections. That history is useful. If a cortisone shot helped for a few weeks and then wore off, the pain is likely to involve the inflamed joint lining that GAE targets. If injections never helped at all, the pain may be coming from somewhere else, such as a mechanical problem, the hip or the spine, and we look for that first. We ask for a four-to-six-week gap after the last steroid injection so that the pain baseline is clear. Our article on knee pain after cortisone stops working covers this in more detail.
You are usually not a candidate for GAE if you have bone-on-bone (grade 4) arthritis or significant deformity, rheumatoid, gouty or infected arthritis, a knee that has already been replaced, locking or giving way from a meniscal tear, an uncorrectable bleeding disorder, reduced kidney function, an unmanageable contrast allergy, or severe arterial disease in the leg.
The evidence for GAE is mixed. Single-arm studies such as GENESIS report meaningful pain relief in roughly half to two-thirds of patients at one to two years, but the triple-blind Australian sham-controlled trial found no significant difference from a sham procedure, and a 2023 health technology assessment judged the effect on pain at 6 to 12 months uncertain.
Uncontrolled studies are encouraging. In GENESIS, 46 patients were treated with permanent microspheres; at two years, average pain on a visual analogue scale fell from about 59 to 38, the WOMAC score fell from 48 to 30, and 57–64% of patients reached a minimal clinically important improvement in pain, symptoms and quality of life. Nine patients went on to knee replacement at an average of 18 months. In a 2025 NYU single-arm trial of 25 patients, 62% met the primary success threshold at 12 months, and the authors concluded GAE provides “clinically significant pain relief for a subset of patients”.
Blinded trials are less clear. In the Australian triple-blind trial (Landers et al., 2023), 59 patients with grade 2 arthritis were randomized to GAE or a sham procedure. Both groups improved, and no difference between them reached statistical significance at 1, 6 or 12 months; the authors wrote that further comparative studies are required before definitive conclusions can be made. The 2023 Canary Islands health technology assessment, which pooled two sham-controlled trials with 80 participants, judged that GAE probably has little to no effect on pain at 6 and 12 months, while noting that it probably does not cause serious adverse events. Larger randomized trials are still under way. In short, the evidence is mixed, and we discuss it that way at every consultation.
| Study | Design | Patients | Main finding |
|---|---|---|---|
| GENESIS (CVIR 2024) | Single-arm, 2-year follow-up | 46 treated, KL 1–3 | Pain and function improved; 57–64% reached a meaningful improvement at 2 years |
| Taslakian et al. (JVIR 2025) | Single-arm, 12 months | 25 | 62% clinical success at 12 months; no severe adverse events |
| Landers et al. (Bone & Joint Open 2023) | Triple-blind, sham-controlled RCT | 59, KL 2 | Both groups improved; no significant difference vs sham |
| Canary Islands HTA (2023) | Review of 2 sham-controlled RCTs | 80 | Probably little to no effect on pain at 6–12 months; low-quality evidence |
A GAE candidacy evaluation is a single visit: we review your symptoms and what you have tried, a standing knee X-ray from the last 12 months (plus any MRI), examine the knee for joint-line tenderness and mechanical symptoms, check blood work for kidney function and bleeding risk, verify insurance, and then say plainly whether GAE is reasonable or who to see instead.
At the first visit we review your symptoms, what you have tried and for how long, and a standing knee X-ray from the last 12 months (an MRI helps if you have one). We examine the knee for joint-line tenderness and mechanical symptoms, check blood work for kidney function and bleeding risk, and verify insurance; our GAE cost and insurance guide explains coverage questions to ask. If GAE is reasonable, we explain the expected range of results and the alternatives. If it is not, we tell you so and suggest who to see next, often in coordination with orthopedics, sports medicine, rheumatology or your primary care physician. For a broader view of options, see GAE as an alternative to knee replacement.
Most published GAE studies enrolled patients with mild to moderate osteoarthritis, Kellgren–Lawrence grade 1 to 3 on a standing X-ray. The GENESIS study excluded grade 4, and the Australian sham-controlled trial enrolled grade 2 only. Bone-on-bone (grade 4) arthritis is usually better discussed with an orthopedic surgeon.
There is no single age cutoff. GENESIS enrolled adults 45 and older (ages 45 to 83 were treated), and the Australian sham trial enrolled ages 18 to 75. Overall health, kidney function and the X-ray grade matter more than age alone.
The studies enrolled patients whose pain had lasted at least three to six months despite conservative care such as exercise therapy, weight management, anti-inflammatory medication or injections. You do not need a set number of injections, but GAE is not a first step.
GENESIS excluded patients with rheumatoid or infectious arthritis, a prior knee replacement in the treated knee, an uncorrectable bleeding disorder, reduced kidney function (eGFR below 45) or grade 4 arthritis. Active infection and severe arterial disease in the leg are also reasons we would not proceed.
Meeting the criteria does not mean it will work. Single-arm studies report meaningful relief in roughly half to two-thirds of patients, but the blinded sham-controlled trials so far give mixed results, and an independent 2023 health technology assessment judged the effect on pain at 6 and 12 months uncertain. We present GAE as an option for selected patients, not a proven replacement for other care.
Call (310) 929-0026 or request a GAE consultation. Orange County patients are seen at our Fountain Valley office at 10900 Warner Ave, Suite 101A, Fountain Valley, CA 92708; Los Angeles and San Fernando Valley patients are seen in Van Nuys and Tarzana. Bring your most recent knee X-rays or MRI, the dates of any injections, and a list of what you have tried.
Medical disclaimer: This article provides general education and cannot determine individual candidacy or outcome. Discuss any change in treatment with your treating physician.
Explore more: Read the complete genicular artery embolization guide, compare GAE vs injections vs knee replacement, and review our Medical Editorial Policy.
Medical content reviewed by Nathanael Sabbah, MD, interventional radiologist. Last reviewed: October 2026.