Overview

Thumb arthritis is common with aging. The condition happens when cartilage wears away from the ends of the bones that form the joint at the base of the thumb. Cartilage is the strong tissue that connects and protects joints and bone. This joint at the base of the thumb also is called the carpometacarpal joint and the CMC joint.

Thumb arthritis can cause pain and swelling. It can weaken the thumb and keep it from moving as it should. This can make it hard to do simple tasks, such as turning doorknobs and opening jars.

Treatment most often involves both medicine and splints. Sometimes thumb arthritis needs surgery.

Symptoms

Pain is the first and most common symptom of thumb arthritis. Pain can be at the base of the thumb when you grasp or pinch an object.

Other symptoms might include:

  • Swelling, stiffness and tenderness at the base of the thumb.
  • Less strength when pinching or grasping objects.
  • Less range of motion in the thumb.
  • The joint at the base of the thumb gets larger or bony.

When to see a doctor

See your healthcare professional if you have swelling, stiffness or pain at the base of your thumb that doesn't go away.

Causes

Thumb arthritis is common with aging. Having had an injury to the thumb joint also can cause thumb arthritis.

The strong tissue that connects and protects joints and bone is called cartilage. Cartilage acts as a cushion. It lets the bones move smoothly against each other.

With thumb arthritis, the cartilage that covers the ends of the bones wears away. Its smooth surface gets rough. The bones then rub against each other, which leads to joint damage.

The damage to the joint might result in the growth of new bone along the sides of the bone that's there. This is called bone spurs. They can cause lumps on the thumb joint.

Risk factors

Factors that can raise the risk of thumb arthritis include:

  • Being assigned female at birth.
  • Being older than 40 years.
  • Having certain conditions that are passed through families. These might include lax joint ligaments or joints that aren't formed correctly.
  • Having injuries to the thumb joint, such as fractures and sprains.
  • Having conditions such as rheumatoid arthritis that change how cartilage forms and how it works.
  • Doing activities and jobs that put high stress on the thumb joints.
By Mayo Clinic Staff