This image shows a normal joint on the left vs. a joint affected by the deteriorating effects of osteoarthritis. In order to fully understand the intricacies of osteoarthritis, it is imperative to first describe arthritis.
Arthritis is an autoimmune disease.
How an autoimmune disease originates or what events lead up to this kind of response is unknown. In fact there exist over 100 different forms of this disease. The main characteristic of this disease is that it is either an inflammatory or degenerative disease that ultimately destroys the joints. As the cartilage breaks down, pieces may break off into the synovial fluid in the joint space. This will lead to further irritation and inflammation.