Joints are places in your body where two bones come together. Arthritis is a problem that causes damage to the normal joint surfaces. These junctions have special surfaces to allow smooth motion. This smooth surface is cartilage, and when the cartilage is damaged, arthritis is the condition that results.
There are two types of arthritis that commonly affect the fingers. These are osteoarthritis and rheumatoid arthritis.
Osteoarthritis
Osteoarthritis, also called wear-and-tear arthritis, is the most common type of finger arthritis. In people with osteoarthritis, the normal cartilage is steadily worn away, exposing bare bone at the joints. The most frequently affected joints in the hand are the knuckles of the mid-finger and fingertip (the PIP and DIP joints), and the joint at the base of the thumb.
Rheumatoid Arthritis
Rheumatoid arthritis causes a different type of joint destruction. Rheumatoid arthritis is a systemic disease that can cause a number of problems. Among these, rheumatoid arthritis can cause inflammation of the soft-tissue surrounding joints. The most commonly affected joints in the hand are the knuckles at the base of the fingers (the MCP joints).