Osteoarthritis of the base of the thumb

Osteoarthritis of the base of the thumb, also known as arthritis of the basal joint of the thumb or arthritis of the wrist metacarpal joint of the thumb, is a degenerative condition.

This joint is located at the base of the thumb where it meets the wrist. It allows the thumb to move and rotate, making it essential for fine and coarse grasping movements.

Osteoarthritis occurs when the cartilage that covers the ends of the bones inside a joint gradually wears out. As the quality of articular cartilage declines, bones may rub against each other leading to pain, swelling, and stiffness in the joint. Over time, osteophytes, which are spiny bone protrusions, can develop, further aggravating joint damage.

It is the most common type of arthritis that affects the hand.

The exact cause of osteoarthritis of the base of the thumb is not fully understood, but certain factors can increase the risk of developing the condition.

These include:

• Age: The risk of developing osteoarthritis increases with age, and arthritis of the base of the thumb is more common in people over 40 years of age.
• Gender: Women are more likely to develop arthritis of the base of the thumb than men.
• Genetics: A family history of arthritis or joint problems can increase the likelihood of developing arthritis of the base of the thumb.
• Overuse or jointtrauma: Repeated thumb movements or previous injuries to the thumb joint can contribute to the development of osteoarthritis.
• Loose joints: 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 reduced range of motion in the thumb.

Activities such as turning a key or opening a jar can worsen symptoms. In advanced stages, the joint may enlarge, and there may be noticeable deformity, as well as weakness in the thumb.

Treatment for osteoarthritis of the base of the thumb aims to relieve pain, improve function, and slow the progression of the disease. Conservative treatment options may include:

• Modification of rest and activity: Avoiding activities that worsen symptoms and modifying hand movements to reduce pressure on the joint.
• Use of a splint to provide support and stability to the joint.
• Medications: Nonsteroidal anti-inflammatory drugs (NSAIDs) to relieve pain and reduce inflammation.

Specialized Physiotherapy (Hand Therapy):

• Treatment protocols by a qualified Physiotherapist can help improve the strength and functionality of the thumb.
• Corticosteroid injections: Injecting corticosteroids into the joint can provide pain relief and reduce inflammation.
• In cases where conservative measures do not offer relief or if the joint damage is severe, surgery may be considered.

Surgical options include:

• the reconstitution of the joint by removing the major polygon, which is the diseased arthritic bone of the wrist and the use of soft tissues such as tendons or follicle, or by using implants
• joint replacement (thumb base arthroplasty)
• joint fusion (arthrodesis)

These procedures aim to reduce pain, improve thumb function, and restore joint stability. An individualized approach should be made depending on the severity of the arthritis, the biological and functional profile as well as, the functional needs of the patient.

If you suspect that you have osteoarthritis of the base of the thumb, it is advisable to consult an orthopedic surgeon specialized in Hand and Upper Limb surgery.