The OED finds 'get knotted in print from 1963 (meaning to to Hell [or worse]). It seems to be British otiginally, but is heard on this side of the water as well. Anecdotally, get bent was heard in the 1950's, but both are possibly older. If you want to be a word sleuth and examine every book, paper or bit of ephemera to find earlier uses, go to it.

Are the dates given in the dictionaries and slang compendia useful in determining when some phrase appeared? They are temporary points of reference, sunject to correction.

Charley, yes, your meaning of 'broke' for 'bent' is also correct and has been noted by the word sleuths.

Catspaw, Sie haben Recht.