In addition to the hip and shoulder implants, the scanner at the airport once got excited about the metal button at the top of my jeans. Why, I can't imagine because a very large number of passengers must have been wearing jeans too. Anyway, they made me undo it and do it up again to be sure I wasn't concealing anything suspicious under it.
When flying to NZ in January, I was advised to get a letter from my GP about my long list of medications, and to put them in a box or bag to be ready to show at Dubai, even though I was only in transit. I brought out the list, ready to show the security officer but she just waved me through. Just the same on the return flight.