Shoulder Embolization Research and Success Rates: An Honest Review

When you search for shoulder embolization, you may see success rates of 85% or 90% and higher. Those numbers are real, but they need context. This article lays out the main published studies, what "success" meant in each one, and the important limits of the research so far, so you can judge the evidence for yourself.

Where the evidence stands in 2026

Shoulder embolization for frozen shoulder (adhesive capsulitis) was first reported in 2014. Since then, studies have come from Japan, Spain, Taiwan, France, and the United States. The results have been consistently positive, but nearly all of the studies share one weakness: they had no comparison group. Every patient received embolization, and researchers measured how they changed over time.

That matters for frozen shoulder in particular, because the condition can improve on its own. Without a control group, it is hard to know how much of the improvement came from the procedure, from time, from physical therapy, or from the placebo effect. As of October 2026, no randomized sham-controlled trial of shoulder embolization has been published. By comparison, knee embolization (GAE) has been tested in randomized sham-controlled trials, which you can read about in what the latest research says about GAE.

Key studies at a glance

The largest studies, in more detail

The 100-patient Japanese feasibility trial (2022)

This prospective study at 5 institutions treated 76 people with frozen shoulder and 24 with painful rotator cuff tears whose night pain had not responded to other care. Average night pain fell from 6.4 to 3.4, 2.3, and 1.6 out of 10 at 1, 3, and 6 months. Forward arm elevation improved from 97 to 151 degrees. No major adverse events occurred, and success rates did not differ significantly between the two diagnoses.

The 118-patient Spanish series (2025)

This retrospective review covered 128 procedures in 118 patients over nearly a decade. Average pain fell from 7.8 to 2.2 out of 10 at 6 months, and flexion improved from about 90 to 143 degrees. Clinical improvement was documented in 89.8% at 12 months. The authors rated it Level 4 evidence, meaning a case series.

The US investigational study (2022)

This was the first US prospective multicenter study, run under an FDA investigational device exemption. Twenty patients were enrolled. Pain fell substantially, and function scores rose by about 45 points on a 100-point scale at 6 months. It ended early during the pandemic, and 6 patients did not reach the 6-month visit.

This article is part of our Embolization Guide.

What the meta-analyses say

A 2026 meta-analysis in the Journal of Vascular and Interventional Radiology combined 12 single-arm studies with 329 shoulders (84% frozen shoulder). It found large improvements in pain at every time point up to 6 months, outward rotation gains averaging about 36 degrees by 3 to 6 months, and function score gains averaging about 59 points. Technical success was 100%, and no severe adverse events were reported. The authors were clear that the evidence "is limited by uncontrolled designs, short follow-ups, and high heterogeneity" and that randomized trials are needed.

A 2026 narrative review of 11 studies with 422 patients reached a similar view: early results are promising, but definitions of success, outcome measures, and follow-up vary so much that studies are hard to compare.

How to read a "success rate"

Success rates are not all measured the same way. Some studies counted success as night pain cut in half. Others used a cutoff on a pain score, a function questionnaire, or a doctor's judgment of "complete recovery." A 2026 cost-effectiveness analysis defined success as only mild pain at 3 months and estimated it at 73.3% for embolization. When success was defined by recovering motion instead, surgical options came out ahead in that model.

It also helps to know the baseline. In a 2008 Oxford study that followed 223 people with frozen shoulder over the long term, 59% had normal or near-normal shoulders an average of 4.4 years after symptoms began. Many embolization studies report results at 6 to 12 months, so their success rates are not directly comparable with long-term natural recovery.

When you hear a number, ask: success at what time point, measured how, and in how many patients? Also note that some study authors report consulting relationships with device companies, which journals require them to disclose.

Comparison studies so far

Only one published study directly compared embolization with another treatment. A 2026 retrospective study from Taiwan compared 21 patients who had embolization with 19 who had arthroscopic capsular release. At 3 months, the embolization group had lower pain scores (2.6 versus 4.7 out of 10). At the 6-month mark, the two groups were statistically similar on every measure. Because patients were not randomly assigned, the groups may have differed in ways that affected results. See shoulder embolization versus surgery for more.

Trials to watch

Several randomized trials are now recruiting:

• Brigham and Women's Hospital in Boston is comparing embolization with physical therapy for chronic shoulder tendinopathy (41 patients planned)
• Chung-Ang University Hospital in South Korea is comparing embolization with usual conservative care (44 patients planned)
• A Taiwanese hospital is comparing embolization with a corticosteroid injection in a triple-masked trial of frozen shoulder (94 patients planned, expected to finish in 2030)

These trials should help answer how much benefit comes from embolization itself.

What this means for you

The research shows that shoulder embolization is technically feasible, appears safe in the hundreds of patients studied, and is consistently followed by meaningful improvement in pain and motion. It does not yet prove that embolization works better than standard care or than time. For many patients with stubborn pain after months of treatment, that level of evidence is enough to consider it, as long as expectations are realistic. Our guides on how long results last and the broader embolization guide can help, and you can learn more about the procedure on our shoulder embolization page.

Frequently Asked Questions

What is the success rate of shoulder embolization?

Published case series report improvement in roughly 85% to 93% of patients, depending on how success was defined. These studies had no comparison group, so the true effect of the procedure itself is not yet known.

Has shoulder embolization been tested against a placebo?

Not yet. As of October 2026, no randomized sham-controlled trial has been published. Several randomized trials comparing it with physical therapy, usual care, or steroid injection are recruiting.

Is there more evidence for knee embolization than shoulder?

Yes. Knee embolization (GAE) has been studied in randomized sham-controlled trials. Shoulder embolization evidence is earlier and comes mostly from single-arm studies.

Keep Reading

• Shoulder Embolization in Manhattan
• Shoulder Embolization Risks and Side Effects: What Studies Show
• Shoulder Embolization vs. Cortisone Injections and Hydrodilatation
• Shoulder Embolization vs. Physical Therapy: Competitors or Partners?
• Shoulder Embolization vs. Surgery: MUA and Capsular Release Compared
• Frozen Shoulder: Causes, Symptoms, and Stages Explained
• Embolization Guide: knee, heel, shoulder, elbow and hip

Sources

1. Okuno et al., J Shoulder Elbow Surg, 2014 — pilot study of arterial embolization for adhesive capsulitis (7 patients)
2. Okuno et al., J Vasc Interv Radiol, 2017 — embolization for adhesive capsulitis resistant to conservative treatment (25 patients)
3. Fernández Martínez et al., Cardiovasc Intervent Radiol, 2021 — mid-term results of embolization for adhesive capsulitis (40 patients)
4. Bagla et al., J Vasc Interv Radiol, 2022 — US investigational device study of adhesive capsulitis embolization (20 patients)
5. Okuno et al., J Vasc Interv Radiol, 2022 — multicenter feasibility trial for refractory nighttime shoulder pain (100 patients)
6. Lanciego et al., J Vasc Interv Radiol, 2024 — midterm outcomes of embolization for adhesive capsulitis (20 patients)
7. Liang et al., Korean J Radiol, 2025 — clinical and MRI outcomes of embolization for adhesive capsulitis (25 patients)
8. Fernández Martínez et al., Cardiovasc Intervent Radiol, 2025 — clinical outcomes of shoulder artery embolization (118 patients)
9. Allaw et al., J Vasc Interv Radiol, 2026 — systematic review and meta-analysis of embolization for adhesive capsulitis (12 studies, 329 shoulders)
10. Leung et al., Skeletal Radiol, 2026 — adhesive capsulitis embolization: a narrative review
11. Khabaz et al., Cardiovasc Intervent Radiol, 2026 — cost-effectiveness of embolization vs MUA vs capsular release
12. Wang et al., J Shoulder Elbow Surg, 2026 — arthroscopic capsular release vs embolization for adhesive capsulitis (40 patients)
13. ClinicalTrials.gov NCT06095050 — embolization vs physical therapy for chronic shoulder tendinopathy (recruiting)
14. ClinicalTrials.gov NCT07336849 — embolization vs usual care for chronic shoulder pain (recruiting)
15. ClinicalTrials.gov NCT07696923 — embolization vs corticosteroid injection for frozen shoulder (recruiting)
16. Hand et al., J Shoulder Elbow Surg, 2008 — long-term outcome of frozen shoulder (223 patients)

Medically reviewed by David Fox, MD, FACS, RPVI. This article is general information, not a substitute for a medical evaluation.

Living with joint or tendon pain that hasn’t improved? Schedule a consultation with Dr. David Fox at Fox Vein & Vascular in Manhattan to find out whether embolization is right for you. Call (212) 362-3470 or request an appointment online.