Osteoarthritis, also known as "wear and tear" arthritis, occurs when the cartilage that cushions and protects the ends of your bones gradually wears away. This leads to pain and stiffness that worsens over time, making it difficult to do daily activities.| orthoinfo.aaos.org
There are more than 100 different types of arthritis and the major types that affect the knee are osteoarthritis, rheumatoid arthritis, and posttraumatic arthritis. There is no cure for arthritis, but there are many treatment options to help relieve pain and stay active.| orthoinfo.aaos.org