Osteoarthritis is commonly seen in middle-aged and elderly people, primarily due to long-term joint wear, leading to degeneration of the cartilage in the joints, causing symptoms of pain, swelling, and discomfort in movement. In contrast, rheumatoid arthritis often begins in younger individuals and is linked to genetics and viral infections, primarily being an autoimmune disease. It is characterized by positive rheumatoid factor, including elevated erythrocyte sedimentation rate and C-reactive protein. Additionally, the treatment methods for these two diseases are different. Osteoarthritis can mainly be managed with massage therapy, injections of sodium hyaluronate, and oral nonsteroidal anti-inflammatory drugs to alleviate symptoms. Rheumatoid arthritis, on the other hand, might require the use of immunosuppressants, steroids, or nonsteroidal anti-inflammatory drugs to relieve pain. Importantly, rheumatoid arthritis commonly affects the small joints of the fingers, whereas osteoarthritis most frequently affects larger joints, such as the knee, highlighting the fundamental differences between the two conditions. (Note: The answers provided are for reference only. Medications should be taken under the guidance of a professional physician, and self-medication should be avoided.)