Your knee joint is made up of 3 bones. The femur (thigh bone), tibia (shin bone) and patella (knee cap). The ends of these bones are covered with cartilage. This specific type of cartilage is called "articular" cartilage.
Cartilage helps the bones to slide past each other. This is the bearing surface of the knee joint and is the cushion of the joint. The cartilage is composed of proteins and water molecules that function as a shock absorber.
Unfortunately, as we age, for various reasons this cartilage starts to wear out. Arthritis is the wearing out of this joint cartialge. As this starts to happen bone will rub on bone, and this hurts.
Why does cartilage wear out? There are a few reasons this may happen, and likely a mixture of all of these is the cause. These reasons include job, body weight, previous trauma and surgery to the joint and genetics. No matter the cause, we have many ways to treat your knee pain without surgery to help you get back on your feet.