Thumb arthritis occurs when the cartilage in the carpometacarpal (CMC) joint wears away.
Thumb arthritis is common with aging and occurs when cartilage wears away from the ends of the bones that form the joint at the base of your thumb — also known as the carpometacarpal (CMC) joint.
Thumb arthritis can cause severe pain, swelling, and decreased strength and range of motion, making it difficult to do simple tasks, such as turning doorknobs and opening jars. Treatment generally involves a combination of medication and splints. Severe thumb arthritis might require surgery.
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Pain is the first and most common symptom of thumb arthritis. Pain can occur at the base of your thumb when you grip, grasp or pinch an object, or use your thumb to apply force.
Other signs and symptoms might include:
- Swelling, stiffness and tenderness at the base of your thumb
- Decreased strength when pinching or grasping objects
- Decreased range of motion
- Enlarged or bony appearance of the joint at the base of your thumb
When to see a doctor
See your doctor if you have persistent swelling, stiffness or pain at the base of your thumb.
Thumb arthritis commonly occurs with aging. Previous trauma or injury to the thumb joint also can cause thumb arthritis.
In a normal thumb joint, cartilage covers the ends of the bones — acting as a cushion and allowing the bones to glide smoothly against each other. With thumb arthritis, the cartilage that covers the ends of the bones deteriorates, and its smooth surface roughens. The bones then rub against each other, resulting in friction and joint damage.
The damage to the joint might result in growth of new bone along the sides of the existing bone (bone spurs), which can produce noticeable lumps on your thumb joint.
Factors that can increase your risk of thumb arthritis include:
- Female sex.
- Age above 40 years.
- Certain hereditary conditions, such as joint ligament laxity and malformed joints.
- Injuries to your thumb joint, such as fractures and sprains.
- Diseases that change the normal structure and function of cartilage, such as rheumatoid arthritis. Although osteoarthritis is the most common cause of thumb arthritis, rheumatoid arthritis can also affect the CMC joint, usually to a lesser extent than other joints of the hand.
- Activities and jobs that put high stress on the thumb joint.