What is Osteoarthritis?
By strict definition, arthritis is defined as “joint inflammation” i.e. the “arthr” denoting part of the latin term for joint, while the “itis” denotes the latin suffix for inflammation. The “osteo” in osteoarthritis denotes the latin term for bone. So the term osteoarthritis, technically describes bone + joint + inflammation. This is not particularly useful since, any form of arthritis will include elements of inflammation, and both “bone” and “joint”, since every joint is formed by the articulation of two bones. Sounds confusing, right? Well it is. It shouldn’t be, but it is. Many of the diagnostic terms used in modern medicine have their roots in language which does not do justice to our current understanding of the pathophysiology of the body’s various bits and pieces.
If you’ve been told that you have “osteoarthritis”, it means that your doctor, or your physio, or someone, suspects (or has confirmed via x-rays) that the cartilage that lines the ends of the joint surfaces of, say your knee joint, has to some degree, worn away. We begin life with a nice thick layering of shock absorbing, slippery and padded cartilage. It is true that this cartilage layer, especially in our weightbearing joints is subjected to a great deal of compression and shear forces on a daily basis. It is normal for cartilage to wear out with age. For some people, this wearing process is faster than for other people. Researchers do not really understand why some people’s cartilage wears out faster than others.
How will Osteoarthritis affect me?
In the past, the presumption has been that the more severe your loss (or wearing out) of cartilage, the more severe will your “arthritis” symptoms be. However, this presumption has been turned on its head in recent years, with research demonstrating only a very weak relationship between the degree of cartilage wear and tear, and the degree of pain or disability one might develop. This is good news for those with a diagnosis of osteoarthritis. It means that you no longer have to presume that a life of disabling pain is a fait accompli. We now understand that there are other factors, in addition to the degree of cartilage wear and tear, that influence the extent to which your “osteoarthritis” is painful or disabling.
Central to these factors is the notion that your body’s sensory pathways, the nerves, have a capacity for changeable sensitivity. That is, the nerve endings that are plugged into, say, your knee joint, can be in a very sensitive state or, let’s say, a less sensitive state. If we stick with the example of the knee joint, the job of your nerve endings is to tell your brain what is happening in your knee. When they (the nerve endings) are in a very sensitive state, they very rapidly, and very effectively transmit every little skerrick of information back up to your brain, bombarding it with a (potentially) distorted picture of what is going on in your knee. Basically, when you have a very sensitive bunch of nerve endings doing their thing, small movements are likely to be very painful. Sustaining static positions is likely to be painful. Getting moving after being still for 20 minutes or so is likely to be painful. And, although things tend to be less painful once your up and moving, extended or intense bouts of activity are likely to be painful.
This pattern of pain behaviour is classic for cases of “osteoarthritis”, but we can no longer attribute these patterns of symptoms solely to the wearing out of cartilage in your joints. We also have to consider that the more ramped up is the sensitivity of your nerve endings, the more amplified is the information (about the state of your knee) being transmitted to your brain. The more amplified the incoming information, the more drastic is the response from your brain. And the response from your brain, typically, is to protect your knee by making the muscles around your knee tight to “guard” the knee. Your brain will also protect the knee by sending out messages to make the nerve endings even more sensitive. We end up with a cycle of increased nerve sensitivity, and protective “guarding” of muscles… ultimately, the result of all that is ongoing pain in the knee, or shoulder, or hip, or whatever particular joint of yours has been diagnosed as osteoarthritic.
The important point here, is that this cycle of nerve sensitivity and muscle guarding, is capable of driving up and sustaining a pain state, regardless of the degree of cartilage wear and tear in your joints. It is possible then, that your osteoarthritis pain, is changeable. Consider this proposition.
To the extent that most of your pain is a product of an interplay between nerve sensitivity and muscular guarding, the significance of cartilage wear and tear is potentially negligible.
Of course, the truth is probably somewhere in the middle… it is likely that the wearing out of cartilage from your joint surfaces, is part of the reason for the ongoing sensitive state of the nerve endings plugged into your osteoarthritic knee or hip or shoulder etc.
How can Physio help me?
So how does all this help you? Well, the most sensible application of all this information, lies in one’s ability to consider that there is at least some component of one’s “osteoarthritis” pain that is a product of the positive feedback loop between nerve sensitivity and muscular guarding… and to the extent that that cycle is broken, one’s pain can be relieved, perhaps even resolved. The next step, logically, would be to find out how this pain cycle might be broken.
This is where a good physio, like our team, can help you.