Carpo- refers to you wrist bones and –metacarpal refers to the long bone between your wrist bones and thumb bones. The joint between these two bones is called the carpometacarpal joint. With age, arthritis may develop at this joint. Thumb arthritis occurs when the cushioning cartilage at the joining ends of these two bones wears away. This may result in pain, swelling, decreased strength and range of motion, making it difficult to do simple activities of daily living. The goal of treatment is to relieve pain and reduce inflammation. Depending on the severity of the arthritis, your doctor may recommend surgery.