The knee is a complicated joint. It is located at a very crucial part of our bodies and provides us with the stability we need for our support, balance, and ability to walk. The thigh bone, shin bone, and kneecap all come together to form the knee joint. So you can see that there are a lot of things going on in this area that require smooth and accurate mechanics for the proper operation of these parts. Many things can affect the knee and knee joint. Deterioration from aging, disease, hereditary factors, the environment, or injury can cause all kinds of abnormalities to be present in and around the joint that can make it difficult for it to function correctly. Osteoarthritis is one of the most common factors that affect the knee. It occurs when the cartilage around the ends of the thigh bone and shin bone deteriorates, leaving no cushion for the bones. You then have bone on bone.