Dear Doctor Ninja,
I’m a man in his 60’s. I read a news story about how having things called Heberden’s nodes on your fingers means you probably have bad arthritis in your knees. I have these nodes on my fingers and now I’m worried about my knees. Should I be seeing my doctor about this?
Heberden’s nodes are usually linked with finger arthritis. They look like small bumps on the back of your finger at the finger knuckle closest to your finger nail.
But what we are dealing with, in both the case of Heberden’s nodes and in the case of the study cited in the news article is the definition of arthritis, or rather the ways in which the word “arthritis” is used.
Cartilage is the extra layer of stuff that caps many of the bone ends in your body to allow them to move smoothly against each other. Strictly speaking, arthritis is the term used to describe any damage or wearing away of cartilage in a joint. We can tell there has been loss of cartilage either by looking at it directly with a camera in the joint (called arthroscopy), or with surgery (not that anyone would open up your knee wide open just to look in it); but also indirectly from tests like x-rays or MRI’s. X-ray or MRI are the most common ways to tell if there’s loss of cartilage.
However, that’s not the way most people think of arthritis. Most people think of arthritis as joint pain caused by loss of cartilage in the joint. Most people think of things like knee and hip replacements when they think of arthritis.
When a study is published that says that bumps on the back of your fingers are potentially a sign for arthritis in your knees that will get worse over the next 2 years, this can understandably cause some distress.
Here’s the thing: There are lots of people out there who have loss of cartilage on their x-ray or MRI who don’t have any pain or loss of function. And this has also been studied.
If you have arthritis (i.e. loss of cartilage) but no pain or loss of function, it is generally considered a non-issue. It’s only when the arthritis (i.e. loss of cartilage) comes with pain or loss of function that anything needs to be addressed.
So what about this study about bumps on the fingers and knee arthritis?
The study in question was a study looking at the association between the bumps on the fingers (Heberdern’s nodes) and the kinds of findings we associate with loss of cartilage in the knee. However, the study in question did not look at whether these findings were related to pain or loss of function.
However, since we know that a lot of people (50% in some studies) have “arthritis” on x-ray or MRI don’t have any pain or loss of function, what does it mean when someone else says having nodes on your fingers is linked to “arthritis” on MRI? How does knowing that your MRI will be more likely to look worse in 2 years help you change anything about the way you live, given that you might still only have a 50% chance of having pain with the worse-looking MRI?
A more expensive wine might make for a better story for whoever buys it, but the price on a bottle of wine doesn’t always make the wine taste better or worse. Price might be linked to taste rating if you can see both the price and taste the taste, but if the wine tastes fine (or even good, or amazing), and the price is low, does the price matter?