What is Thumb Base Osteoarthritis?
The 1st CMC joint is located at the base of the thumb, where the thumb meets the wrist. It allows the thumb a wide range of movement but is subjected to significant load during gripping and pinching. Osteoarthritis at this joint involves cartilage loss, changes in the underlying bone, and local inflammation, leading to pain, reduced stability, and weakness. The condition is distinct from tendon or nerve problems and is a frequent source of hand pain in mid-life and older adults.