Many types of arthritis can affect your elbow, but the main ones are rheumatoid arthritis and osteoarthritis. Rheumatoid arthritis is the most common type of arthritis in the elbow. When you have it, your immune system attacks your body’s healthy tissue and causes swelling in your joints. You get osteoarthritis when your elbow cartilage breaks down over time, which means the bones rub together and cause pain and stiffness.