Cartilage is a thin, elastic tissue that protects the bone and makes certain that joint surfaces can slide easily over each other. Cartilage ensures supple knee movement.

There are two types of joint cartilage in the knees:

  • Fibrous cartilage (the meniscus), which has tensile strength and can resist pressure
  • Hyaline cartilage, which covers the surface along which the joints move

Cartilage will wear over the years; it has a very limited capacity for self-restoration. The newly formed tissue will generally consist for a large part of fibrous cartilage of lesser quality than the original hyaline cartilage. As a result, new cracks and tears will form in the cartilage over time.