lol, I very much doubt they are!
If its anything to go by Petes smashed hand felt awful last time he was on a long journey, and it hadn't even got to temperatures we've had of late. Previous broken bones always feel more cold than others.
When Matt still had his dodgy hip he used to dread this time of year as the pain was excrutiating from the cold setting in and staying there. Petes the same with his knee, both of them contained bits of metal in there, and it don't matter how or what said bones/metal are covered with, they don't make the slightest bit of difference