BALTIMORE (Map, News) - Many people don’t realize how important their thumb is until it becomes painful to use.

Arthritis of the thumb — the most common source of painful arthritis of the hand — can make buttoning a shirt, holding a pen or putting in earrings impossible or painful.

“It is tricky to treat because most types of arthritis surgeries in other parts of your body require replacements and don’t necessarily stand the test of time,” said Dr. Stacey Berner, the director of The Hand Center at Northwest Hospital Center. “There was reluctance for many years to do reconstructive or replacement operations for this joint, and most fail miserably.”

Berner performs a new outpatient arthroscopic surgery to smooth damaged bone joints using only two small incisions. This differs from more common surgeries that leave a scar from the thumb to the wrist.

Arthritis of the thumb occurs when the surfaces between the base of the thumb and the wrist grind together until the cartilage is rubbed off. It is most common in women in their 30s and 40s. It differs from other types of arthritis because the area it affects is the only joint of its shape in the body, Berner said.

“This procedure expands our ability to treat the problem,” Berner said. “We used to shy away from treating younger people because if the bigger operation fails you don’t have a lot of really good bail-out operations. If you should wear out this procedure you can convert it to the bigger operation when someone is older.”