Thumb pain can make everyday activities—opening a jar, turning a key, gripping a coffee mug, or even using a phone—surprisingly difficult. One common cause of pain at the base of the thumb is CMC thumb arthritis, also known as basal joint arthritis.
What Is CMC Thumb Arthritis?
The carpometacarpal (CMC) joint is located at the base of the thumb, where the thumb metacarpal meets a small wrist bone called the trapezium. This joint gives the thumb much of its remarkable range of motion, allowing us to pinch, grasp, and manipulate objects.
Over time, the cartilage that cushions the joint can wear down. As the cartilage deteriorates, movement may become painful and the joint can become stiff, swollen, or unstable. This condition is commonly called osteoarthritis of the thumb CMC joint.
What Does CMC Thumb Arthritis Feel Like?
Pain at the base of the thumb is often the most noticeable symptom. It may be particularly uncomfortable during activities that require pinching or gripping.
Other symptoms can include:
Tenderness or swelling at the base of the thumb
Reduced grip or pinch strength
Difficulty opening jars, turning doorknobs, or using keys
Pain when writing, gardening, cooking, or using tools
Stiffness and decreased thumb movement
A grinding or catching sensation in the joint
Changes in the appearance or position of the thumb as arthritis progresses
Symptoms can range from mild and occasional to persistent enough to interfere with work, hobbies, and daily activities.
Who Gets Thumb CMC Arthritis?
CMC arthritis becomes more common with age and is particularly common in women. Previous injuries to the thumb, joint instability, genetics, and repetitive stress may also contribute to its development.
Importantly, the amount of arthritis visible on an X-ray does not always match the amount of pain someone experiences. Treatment should therefore focus on symptoms, function, and the individual’s needs.
Treatment Without Surgery
Many people with CMC thumb arthritis can manage their symptoms without surgery. Treatment may include modifying activities that aggravate the joint, using a thumb brace or splint, and working with a certified hand therapist on exercises, accomodations and strategies for protecting the joint.
Pain-relieving or anti-inflammatory medications may be appropriate. CBD oils and creams rubbed around the base of thumb and heat or ice may also provide temporary relief. In some cases, a healthcare professional may recommend an injection into the joint to reduce pain.
The best treatment plan depends on the severity of the symptoms and how much they affect everyday life.
When Is Surgery Considered?
Surgery may be considered when pain remains significant despite appropriate nonsurgical treatment and substantially limits daily activities. Several surgical techniques are available for CMC arthritis.
When Should You Seek Medical Advice?
If pain at the base of your thumb is persistent, worsening, or interfering with everyday activities, consider having it evaluated. Thumb pain isn’t always caused by CMC arthritis, and an accurate diagnosis can help determine the most appropriate treatment.
CMC thumb arthritis can be frustrating, but there are many ways to manage it. For many patients, conservative treatment provides relief. When those treatments are no longer sufficient, surgical options may help reduce pain and improve function.
