Joint cartilage is a tough, smooth tissue that covers the ends of bones where joints are located. It helps cushion the bones during movement, and because it is smooth and slippery, it allows for motion with minimal friction.

Osteoarthritis, the most common form of arthritis, is a wear and tear condition that destroys joint cartilage. Sometimes, as the result of trauma, repetitive movement, or for no apparent reason, the cartilage wears down, exposing the bone ends. Over time, cartilage destruction can result in painful bone-on-bone contact, along with swelling and loss of motion. Osteoarthritis usually occurs later in life and may affect only one joint or many joints.