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Thumb Arthritis: Symptoms, Treatment

Thumb arthritis (CMC joint) affects 15% of women over 50. Learn symptoms, treatments from splinting to surgery, and the new Touch CMC prosthesis.

By Joint Pain Authority Team

Medically Reviewed by Medical Review Team, MD
Thumb Arthritis: Symptoms, Treatment

Quick Answer

Thumb arthritis (CMC or basal joint arthritis) is one of the most common forms of hand osteoarthritis, affecting roughly 15% of women and 7% of men over 50. It causes pain at the base of the thumb during gripping, pinching, and twisting motions. Treatment starts with splinting and hand therapy, progresses to cortisone injections, and may eventually require surgery. A new prosthetic implant (Touch CMC 1) received FDA clearance and offers a promising alternative to traditional surgical approaches.


What Is Thumb Arthritis?

The carpometacarpal (CMC) joint at the base of your thumb is one of the hardest-working joints in your body. Every time you grip a jar, turn a key, or pinch something between your thumb and fingers, this joint bears significant force, up to 12 times the force applied at the thumb tip.

Over time, the cartilage protecting this joint wears away, leading to bone-on-bone contact, inflammation, and pain. This is thumb arthritis, also called basal joint arthritis or CMC joint arthritis.

Why the Thumb Is Vulnerable

Unique anatomy. The CMC joint is a saddle-shaped joint that allows your thumb to move in multiple directions. This extraordinary range of motion also makes it less inherently stable than other joints.
High daily use. You use your thumb for nearly every hand task. The cumulative stress over decades eventually takes a toll on the cartilage.
Hormonal factors. Estrogen appears to play a protective role for joint cartilage. The decline in estrogen during menopause may explain why thumb arthritis is twice as common in women.
Ligament laxity. Looser ligaments (more common in women) allow the CMC joint to shift slightly out of alignment, accelerating wear.

Symptoms of Thumb Arthritis

Thumb arthritis develops gradually. Recognizing early symptoms can help you start treatment before significant joint damage occurs.

Early Symptoms

Pain at the base of the thumb during gripping or pinching activities
Aching after prolonged use (writing, gardening, cooking)
Morning stiffness at the thumb base lasting 15-30 minutes
Tenderness when pressing on the CMC joint (the fleshy mound at the base of your thumb near your wrist)

Progressive Symptoms

Difficulty opening jars, turning keys, or snapping buttons
Weakened grip and pinch strength
Visible swelling or bony bump at the thumb base
The thumb begins to look deformed (may shift toward the palm)
Pain at rest, not just during activity

Diagnosis

Your doctor will examine your thumb by pressing on the CMC joint and performing a “grind test” (rotating the thumb while applying gentle pressure). An X-ray confirms the diagnosis by showing joint space narrowing, bone spurs, or subluxation (partial dislocation).


Treatment Options

Treatment follows a step-wise approach, starting with the least invasive options.

Step 1: Splinting and Activity Modification

Thumb spica splint: Stabilizes the CMC joint while still allowing finger movement. Wearing it during activities that trigger pain, and overnight, can reduce symptoms by 50-70% in many patients.
Adaptive tools: Wide-grip utensils, jar openers, key turners, and ergonomic kitchen tools reduce thumb joint stress. Medicare may cover some assistive devices.
Activity changes: Use two hands instead of one for heavy tasks. Avoid sustained pinching when possible. Take breaks during repetitive hand activities.

Why this works: Reducing mechanical stress on the CMC joint gives the inflammation a chance to settle. Many patients with mild to moderate thumb arthritis manage well with splinting alone for years.

Related reading: Ergonomic Tools for Arthritis

Step 2: Hand Therapy

Certified hand therapist (CHT): These specialized therapists (OTs or PTs with advanced hand training) design exercise programs that strengthen the muscles around the CMC joint without stressing it further.
Custom splint fabrication: A hand therapist can make a custom-molded splint that fits better and is more comfortable than off-the-shelf options.
Joint protection education: Learning which movements to avoid and how to use your hands more efficiently can significantly reduce daily pain.

Medicare coverage: Part B covers hand therapy (occupational or physical therapy) with a doctor’s referral. A CHT is the gold standard for thumb arthritis rehabilitation.

Related reading: Hand and Wrist Exercises for Arthritis

Step 3: Cortisone Injections

How it works: A small amount of corticosteroid is injected directly into the CMC joint to reduce inflammation and pain.
Expected relief: 1-3 months of reduced pain. Some patients get longer relief, especially if combined with splinting.
Limitations: Relief is temporary, and repeated cortisone injections may not be advisable long-term. Most hand surgeons limit CMC injections to 2-3 per year.

Medicare coverage: Covered under Part B. Minimal out-of-pocket cost.

Step 4: Surgery (When Conservative Care Fails)

When splinting, therapy, and injections no longer provide adequate relief, surgical options include:

Trapeziectomy (LRTI - Ligament Reconstruction Tendon Interposition)

The traditional gold standard. The trapezium bone (the arthritic bone at the thumb base) is removed and replaced with a cushion made from a nearby tendon. Recovery takes 3-6 months, but long-term results are excellent with lasting pain relief and good strength.

Arthrodesis (Joint Fusion)

The CMC joint is permanently fused in a functional position. Eliminates pain completely but sacrifices some motion. Best for younger patients with high physical demands.

Touch CMC 1 Prosthesis (Emerging Option)

A newer prosthetic implant that replaces the arthritic joint surfaces while preserving motion. The Touch CMC 1 received FDA clearance and early clinical results show promising outcomes including faster recovery than trapeziectomy and good preservation of thumb strength and motion. This is an emerging option. Long-term data (10+ years) is still being collected. Not all hand surgeons offer this procedure yet.

Arthroscopic Debridement

A minimally invasive option for early-stage disease. A small camera and instruments clean out loose cartilage and bone spurs. May delay the need for more extensive surgery.

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When to See a Specialist

Do not wait until your thumb arthritis is severe. Early treatment can slow progression and maintain function.

See a hand specialist or orthopedist if:

Thumb pain persists for more than 2-3 weeks despite rest and over-the-counter treatment
You are having difficulty with daily tasks (opening jars, writing, dressing)
You notice a visible bump or deformity at the thumb base
Your grip strength has noticeably decreased

A hand surgeon or hand-specialized orthopedist can confirm the diagnosis, stage the severity, and create a treatment plan. For Medicare patients, an orthopedist vs. rheumatologist guide can help you choose the right starting point.


Frequently Asked Questions

What does thumb arthritis feel like?

Most people describe a deep ache at the base of the thumb (the fleshy mound near the wrist) that worsens with gripping, pinching, and twisting motions. Opening jars, turning keys, and writing are common triggers. Early on, the pain comes and goes with activity. As arthritis progresses, pain may be present at rest and can wake you at night.

How common is thumb arthritis?

Very common. Studies show that roughly 15% of women and 7% of men over age 50 have symptomatic CMC joint arthritis. Radiographic evidence (visible on X-ray but not necessarily causing symptoms) is found in up to 33% of postmenopausal women. It is the most common site of hand osteoarthritis.

Does thumb arthritis get worse over time?

Thumb arthritis is generally progressive, meaning it slowly worsens over years. However, the rate of progression varies widely. Some people have mild thumb arthritis that remains stable for decades with proper management (splinting, activity modification). Others progress more quickly. Early treatment helps slow the process.

What is the new thumb joint replacement?

The Touch CMC 1 is a prosthetic implant designed to replace the arthritic surfaces of the CMC joint. Unlike trapeziectomy (which removes a bone), this implant preserves bone stock and may allow faster recovery. Early results are encouraging, but it is still relatively new and long-term durability data is limited. Ask a fellowship-trained hand surgeon whether you might be a candidate.

Can you prevent thumb arthritis?

You cannot completely prevent it, especially given genetic and hormonal factors. However, you can reduce risk and slow progression by maintaining hand strength, using ergonomic tools, avoiding sustained forceful pinching, and wearing a support splint during activities that stress the thumb. If you have early symptoms, starting treatment promptly helps preserve joint function.

There is no strong evidence that normal smartphone use causes CMC joint arthritis. However, sustained gripping of a phone or tablet can aggravate existing thumb arthritis. If you have symptoms, try using a phone stand, voice-to-text, and take breaks from extended phone use.

Should I see a hand surgeon or a regular orthopedist?

A hand surgeon (an orthopedic surgeon or plastic surgeon with fellowship training in hand surgery) has the most expertise for thumb arthritis. If no hand surgeon is available, a general orthopedist who treats hand conditions can also evaluate you. Ask whether the doctor regularly treats CMC joint arthritis.


This article is for informational purposes only and does not replace medical advice. Consult with your healthcare provider about the treatment plan that is right for your individual situation.

Last reviewed: March 2026


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