Arthritis is a condition describing inflammation of a joint, and applies to over 100 diseases that have been identified to date. Most of these diseases fall into one of two categories: degenerative arthritis, such as osteoarthritis, or inflammatory arthritis, such as rheumatoid arthritis. Symptoms of most types of arthritis include pain, stiffness, and swelling in the joint.

Explore the topics below for peer reviewed articles that explain how arthritis causes joint pain as well as the differences between degenerative and inflammatory arthritis.

Infections in the tissues of the knee joint and systemic infections may lead to severe knee pain. Learn how infections like septic arthritis, reactive arthritis, and bursitis cause knee pain.

A swollen knee, sometimes called “water on the knee,” is cause for concern. Learn when medical care is necessary, how to treat a knee swelling at home, and how doctors can remove fluid from a knee using processes called joint arthrocentesis and bursal aspiration.

Inflammatory arthritis is a group of conditions characterized by damage to the synovial lining of the joint. Rheumatoid arthritis is one of the most common forms of inflammatory arthritis.

Knee joint pain and discomfort from arthritis can be experienced in different ways: a dull ache, a sharp, stabbing pain, stiffness, warmth, and swelling.

Nonsurgical treatment for trigger finger is aimed at reducing inflammation in the tendon sheaths. Common treatments include ice therapy, NSAIDs, and immobilization with a splint.

Structures that affect the joint, such as muscles, tendons, and ligaments can cause pain during joint movement. These are not forms of arthritis, but they can lead to degeneration in the joint (osteoarthritis).

Inflammation of the sacroiliac joints (SI joints) may be a symptom of one of many inflammatory conditions, but not in every case. Learn the common arthritic and non-arthritic causes of SI joint pain and inflammation.
There are several conditions outside of trauma that often result in knee pain, swelling, and redness. Learn to recognize the symptoms of several of these conditions.