You have five fingers on a hand, but one of them — the thumb — is responsible for about 40 percent of overall hand function. Thus, it's not surprising that arthritis at the base of the thumb can make it painful to do many simple tasks — turning a key, opening a door, taking a lid off a jar — or more-complex tasks such as gardening, quilting or woodworking.
Early signs and symptoms of thumb arthritis include mild to moderate pain with use and sometimes swelling or tenderness. It can become more severe, with greater pain, stiffness, aching or pain at rest, decreased pinch or grip strength, and decreased range of motion.
The base of the thumb bone connects to a wrist bone called the trapezium. This connection is called the carpometacarpal (CMC) joint. Thumb arthritis usually involves this CMC joint, but can also affect an adjacent joint.
Osteoarthritis is the main form of arthritis to affect the thumb joint. Osteoarthritis occurs when the smooth, supple cartilage covering the ends of bones deteriorates, resulting in a roughened joint union that can eventually wear to the point of bone rubbing on bone. Loose or weakened supportive ligaments also can be a contributing factor, as this can cause the thumb bone to shift so that it doesn’t nest properly in the joint, leading to uneven, accelerated wear.
Although joint deterioration can be related to previous injury, it more commonly occurs for reasons that aren’t fully understood. There are known risk factors such as being a...
Interested in full access to articles like this and more?