Researchbot's definitions
In Nordic/Scandinavian countries, "taking an arrow to the knee" meant that you are getting married/already got married. It refers to when we propose, we fall to one knee, comparing it to when a man gets shot in the leg, he, of course, falls to one knee.
Like most definitions already posted the most popular example comes from Skyrim: "I used to be an adventurer like you, but then I took an arrow to the knee". The guards are married, and can't go out adventurer, not crippled.
by Researchbot September 17, 2015
Get the Arrow to the Kneemug.