It’s a common story. Often it starts when my patient was doing something strenuous, perhaps while playing sport or doing some kind of physical activity, or maybe lifting something heavy.
“I felt something go pop, and then the pain came on. Does that mean I’ve torn something?”
We’re not talking here about the kind of painless clicking and cracking that joints sometimes make, often for no apparent reason. (I’ve written another blog about that). This is when there seems to be a definite injury. People often describe it as “I felt something go”. Very often, they’ll be convinced that they’ve ruptured a tendon or a ligament, or at the very least, torn something badly. And while that might be the case, I’m always keen to point out that just feeling a pop on its own doesn’t necessarily mean very much.
I’ll give you an example. On a recent climbing holiday, I was climbing a route that was quite strenuous (for me at least; I’m a very average climber). I missed a hold, ended up a bit out of position, and as I pushed up onto my left foot I felt a definite twang in my left hamstring. Immediately I assumed the worst – that my hamstring had “gone”, and that was the end of my climbing for this trip. Still, I was halfway up a cliff by that time, so I tentatively tried the next move to see what would happen. Nothing gave way, so I carried on, all the time thinking “that’s going to be really sore later”. I didn’t do anything too strenuous after that, but sure enough by the evening, I was limping pretty badly. Uh oh.
The next day, though, it was a little sore, but not too bad. By the time I’d warmed it up and walked on it a bit it had started to ease, and I even managed to climb a few easy routes without giving it too much trouble. The day after, it was very mildly niggly and I climbed my hardest route of the trip.

So, what was the pop? The honest answer is that it’s impossible to say.
There are plenty of sources that will tell you that if you feel something pop, then it means you’ve torn something. Some will even use it in making a diagnosis. My own experience – both with patients in clinic, and in my own sporting endeavours, leads me to be more cautious about jumping to conclusions.
For all the things written online that will try to tell you absolutely definitively what is definitely going on here; the truth is that bodies often behave weirdly, and we can’t always point to an exact cause for a particular experience or sensation. It’s possible that that pop in your knee could be a ruptured ACL; but it’s also not uncommon to feel something pop without there being any major structural damage.
There’s a lot to be said for erring on the side of caution. If you have just felt something “go”, it’s best not to ignore it and carry on, in case it does turn out to be something significant. (In the heat of the moment, being sensible is sometimes easier said than done). If in doubt, do go and get it checked out, especially if the injury happened in a fall, collision or other impact, but don’t necessarily assume the worst. There have been plenty of times I’ve had to work quite hard to convince someone that the damage isn’t as bad as they’d feared!