Pain at the base of the thumb has a way of interrupting everything. You feel it when you pinch, twist a lid or turn a key. If a splint, anti-inflammatory medicine and perhaps an injection have not settled it, you may have come across embolization as a newer idea. This article looks at basal thumb arthritis specifically: what it is, what guidelines recommend, what two small embolization studies found, and where surgery fits.
What basal thumb arthritis is
The joint at the base of the thumb, where the thumb meets the wrist, goes by several names: the first carpometacarpal (CMC) joint, the trapeziometacarpal joint, or simply the basal joint. They all mean the same place. Researchers who classify hand osteoarthritis treat arthritis of this joint as its own type, separate from the forms that mainly affect the fingers.
According to the American Academy of Orthopaedic Surgeons (AAOS), this is the most common site of arthritis in the thumb. Women are 2 to 3 times more likely to get it, and it usually appears after age 50. Typical signs include:
- Pain with gripping or pinching, such as turning a key or opening a jar.
- Pain at night.
- A weak pinch.
- A bump at the base of the thumb.
AAOS makes two points that are easy to miss. Some people have no symptoms even when X-rays show advanced arthritis. And some people who do have symptoms find that they go away over time, with or without treatment. Keep that second point in mind when we get to the studies. For more of how hand arthritis is diagnosed, see hand osteoarthritis causes, symptoms and diagnosis.
Standard care: what guidelines recommend
Most people with thumb arthritis are treated without a procedure. Three major guidelines address it, and none of them mentions embolization.
- Splints (orthoses). The 2019 American College of Rheumatology and Arthritis Foundation guideline strongly recommends a hand splint for thumb-base arthritis. The College's 2026 update summary recommends splints conditionally, noting low-certainty evidence, and adds a conditional recommendation for therapeutic taping of this joint.
- Anti-inflammatory medicine. The 2026 summary strongly recommends both anti-inflammatory gels and anti-inflammatory pills for hand osteoarthritis. The 2018 European recommendations prefer gels and creams first and suggest pills for a limited time.
- Exercise and therapy. Hand exercise is conditionally recommended in the 2026 summary, which also advises referral to occupational therapy when hand use is limited.
- Steroid injection. Conditionally recommended for hand osteoarthritis in both the 2019 guideline and the 2026 summary. The European recommendations generally do not recommend joint steroid injections for hand osteoarthritis, with a possible exception for painful finger joints. AAOS notes that relief can last weeks to months and that injections can be repeated only a limited number of times because of possible side effects.
- Gel (hyaluronic acid) injection. The 2019 guideline recommends conditionally against it for thumb-base arthritis.
These steps come first. Our guide to hand arthritis treatment without surgery explains each one.
What thumb-base embolization involves
Embolization works from inside the artery. In the published thumb studies, the embolic agent was delivered into the radial artery, through a needle at the wrist in one study and a microcatheter in the other. The agent is meant to slow blood flow through small abnormal vessels around the arthritic joint. The idea is that inflamed joint lining grows extra vessels and that pain nerves travel with them. For the hand, that remains a hypothesis. Embolization does not rebuild cartilage or realign the joint.
Two studies have looked at the thumb base specifically. Both are uncontrolled case series, which means every patient was treated and no one was compared with a placebo procedure or a standard treatment.
Questions about your treatment options? Dr. Fox can help.
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The 2021 Japanese study: 31 patients
Inui and colleagues in Tokyo ran a prospective, uncontrolled series of 31 patients. All had thumb-base arthritis graded as Eaton stage II or III, symptoms for more than six months, and no relief from at least three months of conservative treatment.
The technique was unusually simple. The agent, an antibiotic called imipenem/cilastatin, was infused through a very fine needle placed through the skin into the wrist artery, with no catheter. From numbing the skin to removing the needle, the average time was 2.9 minutes. That figure belongs to this technique in this study. It is not a promise for any other setting.
| Measure | Before | 2 months | 6 months | 24 months |
|---|---|---|---|---|
| Pain, 0 to 10 | 7.2 | 3.1 | 2.8 | 2.5 |
| QuickDASH, a hand and arm function questionnaire (lower is better) | 49.2 | 22.1 | 20.9 | 19.5 |
| Patients who rated themselves improved | 84% | 81% | 77% |
No major adverse events were encountered. The published abstract does not list minor side effects. It times its results "after the first procedure," so some patients had more than one, but it does not say how many.
The 2026 U.S. study: 14 patients
Konduru and colleagues published the only U.S. series so far, a prospective, uncontrolled study of 14 patients with thumb-base arthritis at a single private clinic in North Carolina. Here the embolic agent was delivered through a microcatheter in the radial artery.
The average pain score (VAS) went from 8.0 before treatment to 3.1 at 1 month and 2.6 at 6 months. Eleven of the 14 patients (79%) had at least a 50% improvement by the end of the study. No major adverse outcomes were reported, and the authors call for larger studies.
The published abstract does not name the embolic agent, the number of sessions, whether sedation was used, or any minor side effects.
What these two studies do and do not show
They do show that in 45 people with stubborn thumb-base pain, average pain scores were lower after embolization, that the improvement was still present at 24 months in the Japanese group, and that no serious complication was reported.
They do not show the following:
- That embolization caused the improvement. With no comparison group, the results cannot be separated from placebo response or from the natural easing of symptoms that AAOS describes.
- How it compares with a splint, an injection or surgery. No such comparison has been published.
- What happens after two years. There are no data beyond 24 months.
- Whether it changes the joint. Neither abstract reports any effect on the arthritis itself, and neither reports grip or pinch strength.
- How often minor side effects occur. In a separate 9-patient hand study that did report them, the treated hand turned pale in every patient for about 30 minutes, and 4 of 9 had a temporary spasm of the wrist artery.
- Whether later surgery is affected. No study reports how many patients went on to surgery or whether embolization changes it.
Forty-five patients is also far too few to rule out rare problems, including reduced blood flow to the thumb or fingers. A 2026 independent review placed thumb-base embolization in its "hypothesis-generating" category. Our article on what the hand embolization studies show sets these two studies beside the three finger joint studies.
Where surgery fits
The National Institute of Arthritis and Musculoskeletal and Skin Diseases describes surgery as an option when other treatments are not helping and joint damage is extensive. For the thumb base, AAOS describes three main operations:
- Trapeziectomy. Removing the trapezium, the small wrist bone under the thumb, with or without using a tendon for support. AAOS calls this the most commonly performed surgery for the condition in the United States.
- Fusion. Joining the bones of the joint, which gives a strong pinch but less motion.
- Joint replacement with an implant. AAOS notes promising early results but says less is known about long-term results.
According to AAOS, research has not shown one approach to be better than the others at relieving pain and improving function. A 2015 Cochrane review of 11 studies with 670 participants reached the same conclusion. It found adverse events in about 10 of every 100 patients after trapeziectomy alone and about 19 of every 100 when ligament reconstruction and tendon interposition were added, based on low-quality evidence. It also noted that no thumb surgery has been tested against sham surgery.
Recovery takes time. AAOS describes an outpatient operation followed by a cast or splint for 4 to 8 weeks, several months to full recovery, and grip strength that keeps improving for up to 9 to 12 months.
Embolization has never been compared with any of these operations, so no one can say which works better. If your X-rays show advanced arthritis and your thumb is failing you, an opinion from a hand surgeon is worth having whatever else you consider. See hand embolization vs. injections and surgery for more.
Is it worth a conversation?
The patients in the two thumb studies had confirmed thumb-base osteoarthritis and, in the Japanese study, at least three months of standard care without enough relief. Research protocols for hand embolization have excluded people with inflammatory arthritis such as rheumatoid arthritis, Raynaud's syndrome, disease of the arm arteries, and allergy to contrast dye or to the antibiotic used. These are trial exclusions, not formal rules, and they are a sensible list to raise with your doctor.
Dr. David Fox, a board-certified vascular surgeon, evaluates patients for hand and finger embolization in Manhattan. A visit should leave you with a clear view of your options, including the option of continuing standard care. Our main hand and finger arthritis embolization page covers the procedure, risks and insurance, and the embolization guide shows how the hand compares with better-studied joints.
Frequently Asked Questions
What is the CMC joint?
It is the joint at the base of the thumb where the thumb meets the wrist, also called the trapeziometacarpal or basal joint. It is the most common site of arthritis in the thumb.
How many thumb arthritis patients have had embolization in published studies?
Forty-five: 31 in a 2021 Japanese study and 14 in a 2026 U.S. study. Both were uncontrolled case series with no comparison group.
How long did relief last in the thumb studies?
In the 31-patient Japanese study, average pain was 2.5 out of 10 at 24 months, down from 7.2, and 77% of patients rated themselves improved. The 14-patient U.S. study followed patients for 6 months. Nothing is known beyond two years.
Should I try a splint before considering embolization?
Yes. Guidelines recommend splints, anti-inflammatory medicine and hand therapy for thumb-base arthritis, and the Japanese study only enrolled patients who had not improved after at least three months of conservative treatment.
Can I still have thumb surgery later?
No published study reports how embolization affects later thumb surgery, so this is unknown. Ask both Dr. Fox and a hand surgeon how they would approach it in your case.
Keep Reading
- Hand and Finger Arthritis Embolization in Manhattan
- Hand Arthritis Embolization: Am I a Candidate?
- Hand Arthritis Embolization Recovery Timeline
- Hand Arthritis Embolization Research: What the Studies Show
- Hand Arthritis Embolization: Risks and Side Effects
- Hand Arthritis Embolization vs. Steroid Injections and Surgery
- Embolization Guide: knee, heel, shoulder, elbow and hip
Sources
- Inui et al., J Vasc Interv Radiol, 2021: intra-arterial imipenem/cilastatin for refractory thumb-base (trapeziometacarpal) osteoarthritis, 31 patients
- Konduru et al., Hand (N Y), 2026: prospective analysis of transarterial embolization for thumb-base osteoarthritis, 14 patients
- Lee et al., Diagn Interv Radiol, 2024: short-term outcomes of transarterial embolization for hand osteoarthritis, 9 patients (full text)
- Pelage et al., CVIR Endovasc, 2026: indication-stratified review of musculoskeletal embolization
- ClinicalTrials.gov NCT06611007: safety of Lipiodol embolization in digital osteoarthritis, 15-patient pilot (University Hospital Grenoble)
- American Academy of Orthopaedic Surgeons, OrthoInfo: Arthritis of the Thumb
- American Academy of Orthopaedic Surgeons, OrthoInfo: Arthritis of the Hand
- NIAMS: Osteoarthritis diagnosis, treatment and steps to take
- Favero et al., Nat Rev Rheumatol, 2022: erosive hand osteoarthritis and hand osteoarthritis phenotypes
- American College of Rheumatology, 2026: update of recommendations for osteoarthritis of the knee, hip and hand (summary)
- Kolasinski et al., Arthritis Rheumatol, 2020: 2019 ACR/Arthritis Foundation guideline for osteoarthritis of the hand, hip and knee
- Kloppenburg et al., Ann Rheum Dis, 2019: 2018 EULAR recommendations for hand osteoarthritis
- Wajon et al., Cochrane Database Syst Rev, 2015: surgery for thumb (trapeziometacarpal joint) osteoarthritis
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.
