Published on 02 December 2025
Basal thumb arthritis is a common condition that worsens over time. Learn how osteoarthritis affects the thumb joint over four stages, what symptoms to look out for, and how treatment options evolve from early management to thumb joint replacement surgery.
How osteoarthritis affects the base of the thumb
Osteoarthritis is one of the most common types of arthritis in the UK. Specifically, the joint at the base of the thumb, the carpometacarpal (CMC) joint, is one of the most common joints in the body to be affected by osteoarthritis. Basal thumb joint arthritis occurs when cartilage wears away from the ends of the bones in the thumb joint.
Basal thumb joint arthritis can be debilitating as it progresses through the stages and can impair people’s abilities to do simple, everyday tasks such as opening jars, turning on taps, handwriting, lifting and carrying certain items.
There are many reasons why someone might develop thumb arthritis. Conditions such as hypermobility, obesity, hormonal or genetic factors, past injuries, and some occupations may make you more susceptible to the development of arthritis. Jobs that involve repetitive hand and thumb motions, such as trades or sporting roles, can strain the joint and make it painful.
Stage 1: Early signs and subtle symptoms
Early signs and symptoms that you may have arthritis in your basal thumb joint are:
- Stiffness, soreness, pain or aching at the base of the thumb, noticeably worse in the morning or when using the thumb repeatedly
- On pressing the base of the thumb, you may feel tenderness
- Reduced ability to open the thumb away from the hand
- Difficulty in performing everyday tasks due to loss of grip strength
At this stage, you may try to ignore your symptoms or just take over-the-counter medication to manage the pain. Your GP may recommend you apply topical Non-steroidal anti-inflammatory drugs (NSAIDs) to your thumb or to wear a splint. This can support your joint and keep your thumb and wrist from moving too much.
Stage 2: Noticeable discomfort and functional impact
As your arthritis progresses, the pain and swelling will become more persistent, and you may notice more tasks that are becoming difficult with a loss of grip strength and thumb mobility.
Visible thumb joint changes may begin at this stage, starting with a small bump developing at the base of the thumb. These are known as small bone spurs, often measuring less than 2mm.
Most people seek help from a doctor when at this stage, especially if the pain is getting harder to manage with over-the-counter medications, a thumb brace and with rest.
Your GP may recommend you have a long-lasting injection of corticosteroid into your thumb joint to ease pain and irritation and swelling.
Stage 3: Structural changes
By this stage, pain will have increased to the point where it’s persistent, and grip strength and thumb mobility will have reduced and weakened. The main cause of the aching pain is the joint cartilage deteriorating, resulting in it rubbing bone-on-bone.
Stage three thumb arthritis involves significant joint narrowing and the presence of large osteophytes (bone spurs), along with potential cysts and sclerosis. Noticeable changes in thumb appearance or even deformity (caused by bone spurs) can occur at this stage. You may also experience potential thumb joint instability and subluxation (where the thumb collapses inwards).
If all other non-surgical treatments have been tried and your quality of life is being significantly impacted, thumb base joint replacement surgery may be required to correct thumb deformity and restore function. Surgery of this type is often not recommended until stage three or four of thumb arthritis, as the joint responds better.
Stage 4: Severe degeneration and surgical options
Now we reach the final and most painful stages of thumb arthritis. By this point, the basal thumb joint will have deteriorated so much that some patients experience complete immobility of their thumb. Even simple tasks will have become challenging, and you might not be able to work properly.
A thumb joint replacement is typically recommended when conservative treatments have failed to provide lasting relief from severe thumb arthritis. If you have any of the following symptoms, you may require surgery:
- Chronic pain at the base of the thumb that does not respond to non-surgical options
- Reduced pinch and grip strength
- Decreased range of motion or stiffness
- Painful grinding sensation in the joint
- Deformity of the thumb
What is thumb joint replacement?
Thumb joint replacement involves removing the damaged joint surfaces and replacing them with an artificial implant, typically made from metal, plastic, or ceramic. The procedure is mostly performed on the basal joint at the base of the thumb, which is frequently affected by osteoarthritis.
Want relief from thumb arthritis?
Book to see our Consultant Orthopaedic Surgeon, Mr Andrew Smith to discuss thumb joint replacement surgery and other treatment options. Complete our online enquiry form, contacting us via Livechat or give us a call on 01580 363158.