For a knee structure to cause you pain, it has to have nerve pain fibers going to it, simply because it's the nerves that are responsible for carrying pain signals up to your brain telling you that you're hurting. Therefore, anything in your knee that has nerve pain fibers going to it could be a source of knee pain-and that's where the guessing game begins.
The problem here is that there are a lot of structures in your knee that contain pain fibers, such as the synovial membrane, the meniscus, and the bone to name a few-so good luck figuring out exactly which one(s) in particular are the exact culprit. About the only knee structure a person can safely rule out is the articular cartilage that can be seen disappearing on x-rays-knee cartilage actually has no pain fibers going to it, and therefore cannot produce any pain. Isn't that something-the number one structure people associate with knee arthritis can't even give you pain!
So what else have we got? Well, another way of trying to figure out what's causing the pain in knee arthritis is to pinpoint the knee structures that are abnormal, and then blame them. However, there's a problem with this approach too-you can find many knee abnormalities in people that have no pain. For instance...
* researchers studied 319 subjects that had knee arthritis on x-ray. Only 47% of them had any knee pain (Hannan 2000).
* another study looked at 50 people that had knee arthritis but had no pain. 30% of them had BML's, or bone marrow lesions on MRI (Felson 2001).
* in this study, 154 patients over 45 years of age with knee arthritis, were compared to 49 subjects over 45 years of age that had no knee pain or knee arthritis (Bhattacharyya 2003). MRI scans found meniscus tears in 91% of arthritic knees. HOWEVER, 76% of those people with PAIN-FREE knees also had meniscus tears!
From these studies, you can quickly see the problem with trying to figure out the source of one's pain by looking for abnormalities in the knee. As these studies show us, there's a lot of people walking around with no knee pain that have knee arthritis and meniscus tears. While that might seem unbelievable, it's true and well documented in the published arthritis research.
So now what? How does one go about figuring out what's causing their arthritic knee pain?
Well, with the current technology, the most realistic answer is it's just not possible to precisely pinpoint what structure(s) are causing the pain in many cases. However, before you get too discouraged, let me also add that you don't necessarily have to know the exact source of your knee pain to get rid of it...
Perhaps a Better Approach to Getting Rid of Knee Pain
So far we've been looking at knee arthritis from a structural point of view. We know from x-rays and MRI's that cartilage wears down, the underlying bone changes, the meniscus can tear, and so on. We've also noted from the research studies, that in many cases, you can have these changes in your knee and still be pain-free-which leaves us a little empty-handed at times trying to explain what exactly causes arthritis pain.
However dig into the research on arthritic knee function, and you'll get a little different perspective on things. By function, I'm talking about how your knee works and performs. For example, how strong are your knee muscles? How well can you bend or straighten your knee?
So what does the research on arthritic knee function show us? A lot. Here's an example...
* researchers went out into the community and randomly selected 462 men and women that were over 65 years of age (Slemenda 1997)
* x-rays were taken of their knees, as well as the strength of the subject's quadriceps muscles, an important stabilizer of the knee
* it was found that men and women with knee arthritis had much weaker quadriceps muscles than those with no knee arthritis
* researchers also noted that women with painful knee arthritis had much weaker quadriceps muscles than those with non-painful knee arthritis
It's interesting that the people with knee arthritis had much weaker leg muscles than the people without knee arthritis. Even more interesting, is that among the women with arthritis, those with pain had more weakness than those without pain.
Hmm. Apparently there are other problems going on in the arthritic knee other than just the structural abnormalities we see pictured all so clearly on X-rays and MRI's. In the above study, the researchers could actually predict who had knee arthritis and who had painful knee arthritis-simply by looking at whose leg muscles were working the best!
Okay, now we're getting somewhere-and we're in a lot more optimistic position. The fact of the matter is that we shouldn't be concerned so much with things such as cartilage loss, a torn meniscus or bone spurs. We know from many studies that it's quite possible for people to live just fine with these kinds of changes in the knee-so we're going to just let them be.
So what should we be focusing on? Improving the functioning of the knee. Why? Because functional problems, like improperly working knee muscles, seem much more related to one having pain, than how bad pictures of your knee look on an x-ray or MRI. Find out more about this proven, evidence-based approach to eliminating knee pain in Treat Your Own Knee Arthritis.