Osteoarthritis (OA) Thumb

What Osteoarthritis?

Osteoarthritis (OA) is a degenerative joint disease which causes the cartilage surrounding your bones to wear away. Cartilage is tough but flexible and surrounds the ends of your bones allowing them to move over one another forming a joint. When the cartilage wears away bone rubs on bone which gives rise to a painful inflamed joint.

About the thumb.

The thumb is a very complicated joint and moves in several directions.

The base of the thumb is where the thumb bone (Metacarpal bone) attaches to one of the small bones (Trapezium) in the wrist to allow some of this complex movement. Sometimes, due to wear and tear/ injury the cartilage around the bottom of the thumb wears away and the bone begins to rub on the little wrist bone causing pain, discomfort and reduced function.

Why does is occur?

Osteoarthritis is a common degenerative disease affecting joints. Anyone can get it but there are a number of factors that may increase the risk of osteoarthritis:

• Age: tends to affect people aged 40+ as muscles become weaker and joints gradually wear over time
• Gender: Osteoarthritis is more common in females than males (particularly in the hands and knees)
• Weight: being over-weight puts more stress on your joints and can increase your chance of developing arthritis
• Family: some forms of osteoarthritis run strongly in families and can be linked to genetics
• Previous injury: an injury or operation on a joint can lead to osteoarthritis in a joint. Similarly some hard repetitive activities or physically demanding jobs can increase the risk of the condition
• Other joint diseases: such as rheumatoid arthritis / gout can increase the risk of developing osteoarthritis

What are the symptoms?

The main symptom of OA at the base of the thumb is pain in the area on movement (e.g turning a key, opening jars).

People may also experience:

• swelling
• difficulty gripping/ weakness
• Stiffness
• Enlarged appearance of the bone
• Limited movement
• Wasting of some of the thumb muscles
• Altered positing of the thumb bones

What tests might be done?

Your surgeon can often tell you have arthritis by performing simple tests, by looking at your thumb or by asking you about your symptoms.
You may be sent for an X-Ray to confirm the diagnosis or to check that the problem isn’t coming from elsewhere.

What is the treatment?

Non-Operative Treatments:

• Medication: such as non steroidal anti-inflammatories such as ibuprofen can help with swelling/ inflammation and pain killers can help alleviate pain
• Splinting: Sometimes splints can be used to protect and support the joint to help alleviate some of the pain
• Joint protection advice/ aids: Sometimes advice on how to protect your joints throughout every day tasks can help to alleviate pain
• Steroid Injections: Localised injections directly into the affected joint to help reduce inflammation and pain

Operative Treatments:

-Trapeziectomy: The surgeon will make a small incision at the bottom of your thumb and remove the ‘trapezium’ bone in the hand. This means that the bottom of the thumb bone can no longer ‘rub’ on the trapezium bone and cause pain.
Sometimes the surgeon will also ‘borrow’ part of a tendon from your arm to loop into the gap where the trapezium has been removed to help stabilise the thumb bone.
-Fusion: In some cases joints can be ‘fused’ / held together with pins and plates. Pain in OA is caused by bones rubbing onto other bones due to the wearing of the cartilage. By fusing bones together you stop them from being able to move thus stopping the pain.