Thumb Arthritis (Base of Thumb): Symptoms, Causes & PT Treatment
Updated October 20261 minute read
Thumb arthritis (CMC arthritis) is wear of the joint at the base of the thumb, causing pain there with pinching, gripping, opening jars, and turning keys. It's common with age, especially in women. It's not a reason to stop using your hand — physical therapy with a supportive splint, joint-protection strategies, and targeted strengthening helps most people. Surgery is reserved for advanced cases.
What is thumb (CMC) arthritis?
It's osteoarthritis of the basal joint where the thumb meets the wrist — a very mobile joint that takes a lot of load with pinching and gripping.
Symptoms
Common features are aching pain at the base of the thumb with pinch and grip tasks, weakness, stiffness, and sometimes a bump or grinding at the joint. Tasks like opening jars and turning keys are typical aggravators.
What causes it / risk factors
Age, prior thumb injury, repetitive heavy pinch/grip, family history, and being female all raise risk.
How it's diagnosed
Diagnosis is from history and exam, sometimes confirmed with X-ray; as elsewhere, imaging doesn't always match symptoms.
Physical therapy treatment
What a PT does. Your therapist offloads the joint, teaches joint-protection strategies, and strengthens the muscles that stabilize the thumb. Exercises & progression (overview). A supportive thumb splint, joint-protection and adaptive techniques, and targeted thumb and hand strengthening. Recovery timeline. Many people gain meaningful relief over several weeks; arthritis is managed rather than cured.
Treatment options compared
Splinting, joint protection, and exercise are first-line. Injections help some. Surgery is reserved for advanced, function-limiting cases.
Red flags
A hot, red, swollen joint with fever needs urgent evaluation. Significant deformity after injury also warrants prompt care.
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Frequently asked questions
Many people get good relief with a splint, joint protection, and strengthening.
Sources (5)
- Kolasinski SL, et al. 2019 American College of Rheumatology/Arthritis Foundation Guideline for the Management of Osteoarthritis of the Hand, Hip, and Knee. Arthritis Rheumatol. 2020. — PubMed
- Rannou F, et al. Splint for base-of-thumb osteoarthritis: a randomized trial. Ann Intern Med. 2009. — PubMed
- AAOS OrthoInfo: Arthritis of the Thumb. — AAOS OrthoInfo
- Baljer B, et al. Surgery for thumb (trapeziometacarpal joint) osteoarthritis. Cochrane Database Syst Rev. 2026. — Cochrane
- MedlinePlus: Osteoarthritis. — MedlinePlus
This article is for education only and isn't medical advice. Always talk to a licensed clinician about your specific situation.