Articular (joint) cartilage is a thick, durable tissue that coats the ends of the bones where they meet to form a joint. It cushions the joint and allows for smooth, easy movement. It also protects the bone from abrasion and damage. Osteoarthritis in the knee occurs when the cartilage is damaged or breaks down. Unfortunately, cartilage doesn’t heal or regrow on its own.
How does cartilage wear out?
An easy-to-understand explanation is this: Cartilage consists of 60 to 70 percent water. This water buffers the main load of the knee joint, and is also supported by collagen fibers. With age and wear, the water molecules in the cartilage lose their ability to bind. The cartilage wears out, and the result is osteoarthritis, eventually affecting the bones.