Arthritis is one of the most common reasons that people will come to an orthopedic surgeon. I find that more often than not a true understanding of what the term “arthritis” means is the first and most useful step in helping to define a treatment plan that is individually tailored. I aim to help in that understanding with the following paragraphs.
The word arthritis is of Greek derivation and comes from “arthro” meaning joint and “itis” which means inflammation. So, very simply, the term arthritis means inflammation of a joint. Inflammation is the body’s response to insult/injury. The specific insult that occurs with arthritis to produce joint inflammation is the deterioration of the cartilage that coats the ends of bones in a joint. The main purpose of cartilage is to provide a cushion surface between bones so that they do not grind on one another when moved, which is painful. This deterioration can happen in any joint of the body, but most commonly occurs in the hip and knee. So, in the knee, when a doctor looks at an x-ray and sees arthritis, what he or she is looking at specifically is the space in between the thigh bone (femur) and the shin bone (tibia) that was once occupied by cartilage and now there is either no space (bone touching bone) or much less of a space as the cartilage thins. I have found this to be a helpful revelation for people in understanding the meaning of the arthritis as there is nothing that is building up in the knee that we can appreciate on x-ray and can extract surgically. Conversely, it is what we don’t see on x-ray (the space in between the bones that is no longer there) as well as the bones adaptive changes to deal with the lack of cartilage that will diagnose arthritis. It is very analogous to your brake pads wearing thin on your car.
Commonly people will notice significant swelling or “fluid on the knee.” This is part of the inflammatory process that occurs in arthritis (very similar to when you have a bruise and notice swelling) and is not, in and of itself, the root problem.
The deterioration of cartilage can happen for numerous reasons as there are around 100 different forms of arthritis. There are several, however, that are the most common with distinct defining characteristics. There is arthritis that occurs after a trauma, known as “post traumatic arthritis” that occurs because the surfaces of the bone are no longer normal and are prone to more rapid deterioration. There is arthritis that is of rheumatologic origin, where the body’s own immune system attacks the joint and indirectly causes the cartilage to deteriorate. This is commonly known as rheumatoid arthritis. Then, there is the most common type of arthritis, generally referred to as either osteoarthritis, degenerative joint disease, or just simply arthritis. This type is due to deterioration of the cartilage with age. Why some people are more prone to it than others is presently unknown, but likely is multifactorial owing to genetics, lifestyle, and body weight. No matter what the cause of the arthritis is, the end result is typically the same with notable deterioration of the cartilage causing increasing levels of pain.
The next installment will summarize the treatment options for arthritis that are currently available.