Osteoarthritis of the base of the thumb, also known as basal joint arthritis or carpometacarpal (CMC) joint arthritis, is a degenerative joint condition that affects the joint at the base of the thumb. It is the most common type of arthritis that affects the hand.
The thumb’s base joint, called the carpometacarpal joint, is located at the base of the thumb where it meets the wrist. This joint allows the thumb to move and rotate, making it essential for gripping and pinching motions.
Osteoarthritis occurs when the cartilage that covers the ends of the bones within a joint gradually wears away. As the cartilage deteriorates, the bones may rub against each other, leading to pain, swelling, and stiffness in the joint. Over time, bone spurs may develop, further contributing to joint damage.
The exact cause of thumb base osteoarthritis is not fully understood, but certain factors can increase the risk of developing the condition. These may include:
- Age: The risk of developing osteoarthritis increases with age, and thumb base arthritis is more common in individuals over the age of 40.
- Gender: Women are more likely to develop thumb base arthritis than men.
- Genetics: A family history of arthritis or joint problems may increase the susceptibility to thumb base arthritis.
- Joint overuse or trauma: Repetitive thumb movements or previous injuries to the thumb joint can contribute to the development of osteoarthritis.
- Joint laxity: Loose or unstable joints may be more prone to developing arthritis.
Symptoms of osteoarthritis of the base of the thumb may include pain, swelling, tenderness, stiffness, and a decreased range of motion in the thumb. Gripping activities, such as turning a key or opening a jar, may worsen the symptoms. In advanced stages, the joint may become enlarged, and there may be a noticeable deformity, as well as weakness in the thumb.
Treatment for thumb base osteoarthritis aims to alleviate pain, improve function, and slow down the progression of the disease. Conservative treatment options may include:
- Rest and activity modification: Avoiding activities that aggravate symptoms and modifying hand movements to reduce stress on the joint.
- Splinting or bracing: Wearing a splint or brace to provide support and stability to the joint.
- Medications: Nonsteroidal anti-inflammatory drugs (NSAIDs) or pain relievers may be recommended to manage pain and reduce inflammation.
- Hand therapy: Exercises and stretches prescribed by a hand therapist can help improve thumb strength and flexibility.
- Corticosteroid injections: Injecting corticosteroids directly into the joint can provide temporary pain relief and reduce inflammation.
In cases where conservative measures fail to provide relief, or if the joint damage is severe, surgery may be considered. Surgical options include joint reconstruction, joint replacement (arthroplasty) or joint fusion (arthrodesis). These procedures aim to reduce the pain, improve the thumb function, and restore joint stability. Those surgical procedures should be individualised according to the stage of the arthritis, the biological and functional profile and needs of the patient.
If you suspect you have osteoarthritis of the base of the thumb, it is best to consult with an orthopaedic surgeon specialised in Hand and Upper Limb surgery.
