I hope you are recovering well after your surgery, and that you take it easy on your trip.
I don't have any artificial parts, but my understanding (and I'm sure if it's wrong others here will correct me!) that it's not inevitable that you will set off the WTMD. If you do, then you will need to be hand screened.
If it were me, I'd probably give the WTMD one chance.
Here's the party line on the subject:
http://www.tsa.gov/travelers/airtrav...al_1374.shtm#1