Understanding base of thumb arthritis

Did you know that 1 in 3 to 4 women over the age of 50 will develop osteoarthritis (OA) at the base of their thumb? While this condition is less common in men, the symptoms and causes are the same for both genders.
Osteoarthritis is a degenerative joint condition that typically results in pain, swelling, and reduced mobility at the affected joint. It can arise from previous trauma, repetitive stress, or chemical changes within the joint that alter the surfaces and surrounding tissues over time. A particularly painful form of OA occurs at the base of the thumb, known as thumb osteoarthritis.
What is Thumb Osteoarthritis?The joint at the base of the thumb, located on the thumb side of the wrist, is called the first carpometacarpal joint (CMCJ). This joint is unique because it allows for a wide range of movements, including opposition, which enables the thumb to touch and pinch the fingertips. This ability to oppose the fingers is essential for countless hand functions—from gripping objects to fine motor tasks like writing or sewing.
However, because the CMCJ supports such complex movement, it relies heavily on the soft tissues around it (ligaments, tendons, muscles) for stability. In cases of thumb osteoarthritis, these stabilizing structures become compromised, leading to pain and dysfunction.
How Does OA Affect the CMCJ?Throughout our lives, the first CMCJ endures a great deal of wear and tear. It positions the thumb so that it can participate in almost every activity involving our hands. It also absorbs and distributes pressure from activities like pinching and gripping. Under normal conditions, the soft tissues around the joint stabilize it, allowing it to tolerate the forces applied during these activities.
However, osteoarthritis affects both the bone and the soft tissues. As the joint capsule and ligaments around the CMCJ loosen and deteriorate, the bones can shift out of alignment. This misalignment leads to the development of joint deformities, which are often seen in advanced stages of thumb OA. These deformities result from imbalances in muscle strength, ligament integrity, and the way the bones move during different activities.
How Can Hand Therapy Help?If you are experiencing pain or stiffness in the base of your thumb, hand therapy can help by:

• Assessing the Pattern of Deformity: We evaluate how the joint is shifting during use and how it sits at rest.
• Restoring Joint Alignment: Through targeted exercises and manual techniques, we work to reposition the joint and restore proper alignment.
• Balancing Soft Tissues: By identifying which structures are loose and which are tight, we can bring balance back to the muscles, ligaments, and tendons, helping to stabilize the thumb.

Hand therapists are skilled in using custom splints, exercises, and other therapeutic interventions to relieve pain, improve function, and prevent further joint deterioration.
Get the Most Out of Your Thumb!If you’re suffering from thumb osteoarthritis, there are effective treatments that can help reduce pain and improve function. Contact us today to schedule an assessment and start your journey toward healthier, pain-free thumb movement.
Call us today at 08 8339 HAND (8339 4263). We’re here to help!