Ask a Therapist: Thumb Arthritis

Certified Hand Therapist Michelle McMurray, MOT, OTR/L, CHT discusses thumb arthritis, also known as basal joint arthritis.

Basal joint arthritis, or thumb arthritis, is the most common site of arthritis in the hand.  This may also be referred to as the CMC (carpometacarpal) joint.  Pain typically occurs at the base of the thumb where the hand meets the wrist.  People typically report pain and weakness with grasping or pinching activities. Most people do not realize how important this particular joint is to the function of the hand until it hurts.  The amount of force transmitted through the CMC joint holding a 1-pound object at the tip is amplified to over 13 pounds at the CMC joint.  Basic activities of daily living can require between 6 and 8 pounds of pinch at the tip of the thumb, which would be amplified more than 10 times that at the base of the thumb!  Over time, this can cause break-down of the joint with loss of cartilage (the smooth part of the joint) and inflammation.  This is sometimes a painful process.

When this occurs in the body, what options do we have to feel better?  Most people do not choose surgery as their first option, and it is often not recommended as the first option.  Initial options may include injections, splinting, medications and/or rest.  Additionally, there are modifications that can be made to our daily activities which may also help to decrease the pain.

Here are a few examples of some easy and inexpensive ways to protect your hands to decrease the stress and inflammation at your thumb:

1. Avoid pinching small objects if this is an option.  Use the larger joints in your hand to perform an activity, such as gripping a handle with all fingers versus pinching with the thumb and index finger.  Grip items from the side versus pinching to pick up paper files.
2. If it is your dominant hand, modify your writing instrument. Increase the diameter with rubber grips, or wrap it to a custom level to decrease the amount of pressure required for the task.  Coban or athletic tape works great, and both are inexpensive.
3. Use adaptive equipment to decrease stress on joints. This can be something as simple as a non-slip jar opener or lightweight tools.  There are many adaptive tools that are designed to decrease stress on joints, such as extenders for door knobs and keys.
4. When using your cell phone, hold it in your palm and use your index finger to surf with versus both thumbs to hold and scroll.
5. Make multiple trips when doing a task instead of trying to carry several items, such as plastic grocery bags, at once.
6. If there is a tool for a task, use it instead of your fingers. For example, use scissors to cut open a bag instead of ripping it open with your fingers.

Certified hand therapists are knowledgeable about activity modifications and joint protection.  To find a certified hand therapist in your area, visit htcc.org. To learn more about thumb arthritis, visit www.HandCare.org.

Michelle McMurray is an occupational therapist who is a certified hand therapist.  She practices at  Rock Valley Physical Therapy in Bettendorf, Iowa.  She has been a member of ASSH since 2009 and is a member of the Public Education Committee.  She is also a member of the American Society for Hand Therapists.