I have had a metal hip for three years, and when I pass through airport security I always set off the alarm. However, it is now part of my life that I get screened 100%, and when the TSA Officers can see that you aware of the procedures etc it doesn't take that long to get it done. I ensure my shoes are placed on the belt for x-ray, and place everything else in my carry on so that I don't have anything else metal, apart from my hip.
Procedure.
1. You sit down while they use the wand over your legs and feet.
2. Then you stand while they use the wand over the rest of your body,
3. Then when it is apparent the only part of your body that sets off the wand is my hip, they give me a a brief pat down. (they always ask first)
4. Its all over and done with in a matter of minutes, and the longest part is putting my shoes, belt etc back on.
Its a small price to pay for security, and I get the same procedure when I go through airports in Australia. I have read posts on TSA Agents with a bad attitude etc, but have not struck one thus far.