I had a few mishaps after my first TKR. Scanners were a new thing at the time and most smaller airports only had metal detectors, which would set off every time and I'd have to be patted down. (this was in 2010-11 and security might have been tighter then?) I would announce I had an artificial knee, set the metal detector off and then have to go to the side to get patted down. I learned quickly to get in line for a scanner (the big thing you stand in with your arms held out) and also to make sure you were in the line where the scanner actually
worked...... Nothing is more frustrating than to stand in line only to get up to the scanner and they say it doesn't work so you only have the metal detector to go through and you have to get patted down again.

(and of course they won't let you go into a new line)
Having a card in your wallet saying you've had a joint replaced does absolutely nothing. I make every attempt to get in a security line with a working scanner, announce I have an artificial knee, follow their instructions and hopefully make it through with no trouble.
We are going on a quick trip to Vegas in Sept and will be flying out of Paine Field (Everett, WA) which is a very small airport with only 4 gates BUT new scanners and NO security lines. Heaven!!! Being right next to the big Boeing Everett plant, it'd better have the latest technology and security whizzbangs to make life easier! This will be my first airline trip with two new joints.