Arthritis of the Thumb Base Fundamentals

The basilar joint of the thumb, or carpometacarpal (CMC) joint, is unique because it provides mobility and stability. However, years of use or injuries may cause dysfunction and pain in this joint. This problem occurs when the cartilage buffer between the bones that permits pain-free movement is worn away and the bones rub against each other. This cartilage loss can result in bone-on-bone friction, , and pain at the thumb base. Arthritis at the small joint at the thumb base is also referred to as "CMC Arthritis" or "Basal Joint Arthritis."

What are the causes?

The disease usually develops over a period of several years. Occasionally, it is accelerated by an injury or fracture. However, arthritis conditions are typically the result of the natural aging process and the wear and tear that comes with daily use. Women over 40 generally are more often affected by arthritis of the thumb base than men are by a ratio of 10 to 1.

Swelling at the thumb base, occasional warmth about the area, tenderness to the touch and pain when pinching or grasping, can indicate arthritis of the thumb base. Turning door knobs or jar lids and opening car doors can become difficult for those with this condition. The pain limits function and its intensity varies depending on your activity level. As the disease progresses, the joint at the thumb base may appear enlarged and swollen. Eventually it becomes more difficult to open the hand around large object.

What are the benefits of treatment?

Early symptoms of arthritis often respond to splinting, rest or injection of anti-inflammatory medication into the thumb base. Eventually, however, like other forms of arthritis, this degenerative disease will worsen over time. If the arthritis becomes so painful that it limits daily activities, surgery is the only option for definitive relief. Following surgery, most patients experience complete or near-complete pain relief along with the recovery of a satisfactory range of motion.

What are the risks of treatment?

Risks include nerve injury, infection, bleeding, and stiffness. Reflex sympathetic dystrophy is a rare condition individuals could develop and results in generalized pain, swelling and stiffness of the entire hand.

Reviewed by a Cleveland Clinic medical professional.

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