Why Did My Knee Pain Come Out of Nowhere?

I’ll run Part II of Morton’s neuroma next time. I realize that since this isn’t a “Saving My Feet” blog, people aren't so interested in trouble-shooting problems with their metatarsals. However, I will note that PFPS is mentioned briefly in the second installment :).

Anyway I recently got a long comment at the end of “On the Virtues of Going Slooooowwwww” that included a line I found interesting:

It just seems strange that I had zero issues with my knees up until someday 15 months ago and they were to never be the same.

Yes, this does seem strange, I agree.

But yes, this is also very common, I’m convinced as well.

I referred the commenter to another post I did, one of my favorites. Sometimes I like to scratch an epistemological itch and try to figure out something important. In Saving My Knees, such a moment occurred when I realized that when measuring rate of change, the perceived rate will be greater as your measuring instrument becomes more precise. (I’m sure others have noticed this same phenomenon, and some statistician’s name is appended to a law stating as much.) This has huge implications.

Anyway, back to the matter of knee pain coming out of nowhere. The post I referred to is about breakdown points. The knee is a load-bearing structure, subject to forces in multiple planes. Physical structures can have breaking points, or tipping points, up to which everything may seem fine externally. So just before that tipping point is reached, there may be the absence of any discomfort whatsoever. But there could be a fine line between no pain and the emergence of some pain that then goes on to worsen to chronic pain rather quickly, which then proves practically incurable.

The tipping point analogy is intriguing, I think, because it can be analyzed in a number of ways in the context of structures. Imagine a cup that withstands the impact from being dropped say 16 inches, but from 17 inches shatters into pieces. Obviously, that’s a dramatic change in state, from whole to irreparably broken, that's caused by a small shift in our initial variable (the height from which it's dropped). That’s not what happens to your knees (especially because they’re not inaminate objects with no ability to heal), but if your knees exist in a condition of precarious homeostasis when you are pushing them too hard, maybe you are close to crossing a thin line that will send you into a downward spiral of pain and misery.

And once you hit that tipping point – once you land on the wrong side of that slim divide that separates no pain and pain – the unfortunate thing is it can take a long time to get back on the right side. But I would argue that your knee pain didn’t exactly come out of nowhere. Instead,  you approached a dangerous line, probably multiple times, that you didn’t even know you were nearing – and finally pushed across it, with disastrous results.