Osteoarthritis (OA) is a degenerative joint disease. It occurs when the cartilage between your bones disintegrates.
Tendonitis is when a tendon is inflamed. It can happen to any tendon in the body. When a tendon is inflamed, it can cause swelling, pain, and discomfort.
Arthritis is the term given to a group of conditions that cause decreased range of motion, and inflammation, pain, and stiffness of the joints.