The symptoms of arthritis can be vague and confusing. There are more than 100 types of arthritis and related rheumatic conditions, so determining what is causing the symptoms can be difficult. The two most common forms of arthritis are rheumatoid arthritis and osteoarthritis. Rheumatoid arthritis usually first affects the small joints, such as the wrist or fingers, and patients experience morning joint stiffness that gets better in an hour or so. The joints also may be swollen and sore.