Thumb-Base Arthritis
Wear of the joint at the base of the thumb, where the thumb meets the wrist, causing pain with pinching, gripping and twisting.
The joint at the base of the thumb - the basal, or carpometacarpal, joint - is a saddle-shaped joint that gives the thumb its remarkable range of movement. That mobility comes at a cost: the joint is under high load every time you pinch, and it is one of the most common sites of arthritis in the hand.
As the smooth cartilage surface wears, the bones move less smoothly against one another and the surrounding ligaments loosen. The result is pain at the base of the thumb, usually worst with pinch and grip.
Thumb-base arthritis is common with age, and it is far more common in women. Many people manage it well for years without an operation.
Loading anatomy
Common symptoms
- Aching pain at the base of the thumb, in the fleshy web between thumb and wrist
- Pain when opening jars, turning keys or door handles, or pinching small objects
- Weakness of pinch - things slip out of the hand
- Swelling or a bony prominence at the thumb base
- Grinding or a catching sensation with thumb movement
- In advanced cases, a change in the resting shape of the thumb
Causes and contributing factors
- Age-related wear of the cartilage surface, which is the most common cause
- Previous injury to the thumb base, including old fractures or dislocations
- Ligament laxity, which allows the joint to shift slightly with load
- Inflammatory arthritis such as rheumatoid arthritis
- A family history is common
How it is evaluated
Evaluation focuses on where the pain is, what movements bring it on, and how much it is limiting daily activity - because that, more than the appearance of an X-ray, drives treatment decisions.
Examination includes specific tests of the thumb base and careful assessment of nearby structures, because thumb pain has several possible sources that can coexist.
- Examination of the thumb-base joint, including a grind test
- Assessment of pinch and grip strength
- Checking for other common causes of thumb-side pain, including tendon irritation at the wrist and carpal tunnel syndrome
- X-rays, including views that show the thumb-base joint clearly
Clinical detail
Radiographic stage and symptom severity correlate poorly. Advanced radiographic change may be minimally symptomatic, and early change may be very painful. Treatment is directed at the patient, not the film.
Coexisting pathology is common - de Quervain tenosynovitis, scaphotrapeziotrapezoid arthritis and carpal tunnel syndrome may all be present alongside basal joint arthritis, and each may contribute to the overall symptom pattern.
Nonsurgical treatment
Most people begin with nonsurgical treatment, and many continue to do well with it long term. The aim is to reduce load on the joint and settle the inflammation around it.
- A thumb splint or brace, worn for activity or at night
- Hand therapy, including strengthening of the muscles that stabilise the thumb base
- Adapted tools and techniques for high-load tasks - larger handles, jar openers, different pinch patterns
- Anti-inflammatory medication where appropriate and safe for you
- A corticosteroid injection into the joint, which can provide relief for a period of time
Surgical treatment
Surgery is considered when pain continues to limit daily life despite nonsurgical treatment. The goal is to relieve pain and restore useful pinch and grip.
Several established operations exist for thumb-base arthritis, and they differ in how they address the worn joint. Which approach suits a particular person depends on the pattern of arthritis, hand demands, age and other individual factors. The options and their trade-offs are discussed in consultation.
- Procedures that remove or resurface the worn joint surface
- Procedures that reconstruct or reinforce the supporting ligaments
- Joint fusion in selected situations, particularly for high-demand hands
Clinical detail
Trapeziectomy with or without ligament reconstruction and tendon interposition, arthrodesis and arthroplasty have each been studied, and comparative trials have generally not established the clear superiority of one technique for all patients.
Technique selection therefore rests on the individual: stage of disease, scaphotrapezial involvement, thumb metacarpal position, functional demand and patient priorities.
Recovery
Recovery after thumb-base surgery is measured in months rather than weeks. A period of immobilisation is followed by a structured programme of hand therapy.
Pinch strength is usually the last thing to return, and it improves gradually over many months.
- A cast or splint for a period after surgery
- Hand therapy to restore motion and then strength
- A realistic timeline and specific restrictions are set out before surgery
When to seek urgent care
Seek immediate medical attention - an emergency department - if you experience:
- Sudden severe thumb pain after an injury, particularly with deformity
- Inability to move the thumb after trauma
- Redness, heat, fever or rapidly increasing swelling, which may indicate infection
This list is not exhaustive. If something about your hand worries you, have it looked at.
Frequently asked questions
Will a splint make my thumb weaker?
Splints are generally used for specific activities or at night rather than continuously, precisely so the hand keeps working. Hand therapists often pair splinting with strengthening for the muscles that support the thumb base.
How long does a cortisone injection last?
It varies a great deal. Some people get relief for many months, others for only a few weeks. Injections are generally not repeated indefinitely, and the response is one piece of information used in planning what comes next.
Will my thumb be normal after surgery?
The aim of surgery is to relieve pain and restore useful function. It does not recreate a normal, undamaged joint, and pinch strength after surgery is not the same as pinch strength before arthritis developed. Realistic expectations are part of the discussion before any decision.
Related conditions
Hand & Finger Fractures
Broken bones in the fingers or the metacarpals - the long bones of the palm - which may be treated with or without surgery depending on position and stability.
Tendon Injuries
Cuts, ruptures or damage to the cords that connect muscle to bone and make the fingers and thumb move.
Carpal Tunnel Syndrome
Pressure on the median nerve where it passes through a narrow tunnel at the wrist, which can cause numbness, tingling and weakness in the hand.
Discuss thumb-base arthritis with Dr. Champagne
A consultation begins with understanding your symptoms, how they affect what you do, and what has already been tried.