Osteoarthritis

Osteoarthritis (OA) refers to degenerative (wear and tear) change that can occur in any joint in the body. When arthritis develops the articular catilage (lining cartilage) is slowly rubbed away eventually leading to bone on bone contact.

So called secondary OA can occur due to a misshapen joint which may follow from fracture or trauma or due to abnormalities of growth (eg dysplasia and perthes). Femoro-acetabular impingement is another condition that is thought to lead to OA. The abnormal shape causes abnormally high stresses in the joint and over time leads to cartilage damage and degeneration. Primary OA occurs in the absence of any trauma or shape abnormality. There may be hereditary (genetic) factors and/ or environmental factors that predispose to the development of primary OA. There is a great deal of research ongoing to try to understand the causes of primary OA.

With arthritis the articular cartilage wears away and quite commonly one side of the knee, usually the medial, is affected in which case if surgery is considered then partial or unicondylar replacement may be considered rather than replacing the whole knee (total knee replacement).