Thumb base arthritis: symptoms, causes and treatment options explained
Thumb base arthritis is a common cause of hand pain, particularly in women over the age of 50. It can make everyday tasks such as opening jars, turning keys or holding a cup of tea uncomfortable and frustrating.
In this article, consultant hand and wrist surgeon Mr David Bodansky explains what thumb base arthritis is, why it develops, the symptoms to look out for and the most effective treatment options available.
What is thumb base arthritis?
Thumb base arthritis, also known as basal thumb arthritis or carpometacarpal (CMC) joint arthritis, affects the joint at the base of the thumb where the thumb meets the wrist. This joint allows the thumb its wide range of movement, enabling gripping, pinching and grasping.
The joint most commonly involved is the trapeziometacarpal joint, formed between the first metacarpal bone and the trapezium. Over time, the smooth cartilage that cushions this joint can wear away, leading to osteoarthritis. As the cartilage thins, the bones begin to rub against each other, causing pain, inflammation and reduced function.
What causes thumb base arthritis?
The most common cause is osteoarthritis, often described as age-related “wear and tear” of joint cartilage. However, several factors increase the risk:
Age and gender
It is more common in women, particularly after the menopause, suggesting a hormonal influence.
Previous injury
A past fracture, dislocation or significant ligament injury around the thumb can increase the likelihood of developing arthritis later in life.
Joint laxity
Some individuals naturally have looser ligaments, which may place greater stress on the joint over time.
Family history
There may be a genetic predisposition in some cases.
What are the symptoms of thumb base arthritis?
Symptoms usually develop gradually and may include:
- Pain at the base of the thumb, especially when gripping or pinching.
- Swelling and tenderness over the joint.
- Weakness when opening jars or turning keys.
- A grinding or clicking sensation (crepitus).
- Reduced movement or stiffness.
- In more advanced cases, visible deformity of the thumb.
Pain may initially occur only during activity, but as the condition progresses it can become more persistent, sometimes occurring even at rest.
How is thumb base arthritis diagnosed?
Diagnosis is usually made through a detailed clinical assessment. A specific manoeuvre known as the grind test (gently compressing and rotating the thumb base joint) often reproduces the pain.
An X-ray confirms the diagnosis and helps assess the severity of cartilage wear, joint narrowing and any associated deformity. The degree of change seen on X-ray does not always correlate directly with symptom severity.
Treatment options for thumb base arthritis
In early or moderate cases, conservative management is often very effective:
- Activity modification to reduce strain on the thumb.
- Anti-inflammatory medication.
- Hand therapy to strengthen supporting muscles and improve joint mechanics.
- A supportive thumb splint, particularly during activities.
- Corticosteroid injections to reduce inflammation and pain.
Many patients achieve good symptom control with these measures and may not require surgery.
Surgical treatment for thumb base arthritis
If symptoms remain severe despite appropriate non-surgical treatment, thumb base arthritis surgery may be considered.
The most commonly performed procedure is trapeziectomy, where the arthritic trapezium bone is removed. This is often combined with ligament reconstruction and tendon interposition (LRTI) or other stabilisation techniques to maintain thumb stability and function.
Surgery is generally very successful in relieving pain and improving grip and pinch strength. Recovery typically involves a period of immobilisation followed by structured hand therapy, and improvement can continue for several months.
Thumb base arthritis is a common and often frustrating condition, but it is highly treatable. If you are experiencing persistent pain at the base of the thumb, consult with Mr Bodansky via his Top Doctors profile to discuss the most suitable treatment options.