“I Took an Arrow in the Knee” is a catchphrase from the video game The Elder Scrolls V: Skyrim.
Can most commonly be seen as comments on youtube, hoping other gamers will recognize the comment and give it a thumbs up. or recognize the inside joke on a random video.
Also used as a reason you're no longer doing something awesome.
"i used to hunt crocodiles, until I took an arrow in the knee"
"I used to think Nothing Else Matters, until I took an arrow in the knee"