It is a progressive joint disease associated with aging.
Many elderly people have some degree of osteoarthritis.
It might be found in the knees, hips, or any other joint. In the spine, osteoarthritis can affect the facet joints, which enable the body to bend and twist. As these joints deteriorate, cartilage may become inflamed and start to fray like a well-used rag. The fraying process may cause pieces of cartilage to break away from the joint surfaces. As the joints are stripped of their cartilage, the once smooth, slick surfaces designed for friction free movement are lost.