Causes, incidence, and risk factors
Arthritis involves the breakdown of cartilage. Cartilage normally protects the joint, allowing for smooth movement. Cartilage also absorbs shock when pressure is placed on the joint, like when you walk. Without the usual amount of cartilage, the bones rub together, causing pain, swelling (inflammation), and stiffness.
You may have joint inflammation for a variety of reasons, including:
- An autoimmune disease (the body attacks itself because the immune system believes a body part is foreign)
- Broken bone
- General “wear and tear” on joints
- Infection (usually caused by bacteria or viruses)