Your doctor can give you a card attesting to your condition; just show it. My mother-in-law has a hip replacement that set off every metal detector at the White House on a tour last Christmas -- she showed her statement and everything was cool. (An 88 year old woman is gonna attack the White House? Riiiiiiiiiiiiight!)

Any terrorist worth his or her salt wouldn't use a metallic weapon anyway. This official paranoia is dumb, dumb, dumb but it makes the politicians feel good, I guess. (I don't object to a reasonable amount of scrutiny, but it's gotten silly.)