Airport security no longer allows medical documentation -- it is too easy to forge these kinds of documents. I have had both of my knees replaced and have metal rods in both legs. I can no longer walk distances and travel either in a wheelchair or scooter. Airport security waves a wand over each of my legs warning, wherever it beeps, they have to touch. They have always been respectful to me, running the back of their hand over my legs, and across my back where I have a metal implant in my hip. I've learned not to wear an under-wire bra, but when I do, again they use the back of the hand - I've never been felt up. Of course, there are always bad apples in the barrel, but if this slight imposition makes it safer for everyone to fly, I don't allow myself to get all upset about it. The nicer you are to them, the nicer they are to you.