Inflammation

Extended Definition

Inflammation is a complex biological response that occurs when your body’s immune system reacts to harmful stimuli, such as damaged cells, irritants, or pathogens. While inflammation is part of the body’s healing process, chronic or excessive inflammation can cause tissue damage and pain.

In joints affected by osteoarthritis, inflammation develops as cartilage breaks down and tiny particles of damaged tissue irritate the joint lining (synovial membrane). This triggers an inflammatory response that causes the membrane to produce excess fluid, leading to joint swelling (effusion), warmth, and increased pain. The inflammatory process also releases enzymes and chemicals that can further damage cartilage, creating a harmful cycle.

The five classic signs of inflammation are: redness, heat, swelling, pain, and loss of function. In joints, this might manifest as visible swelling, a warm feeling when touching the joint, stiffness, pain during movement, and difficulty performing normal activities. Anti-inflammatory treatments—including medications like NSAIDs and corticosteroids, as well as non-drug approaches like ice therapy and rest—aim to reduce inflammation and break this cycle of damage.