http://www.orthopodmatch.com/interview-calendar/

Your safest bet is to go (looking at this years calendar) for a week, 23rd-31st/1st.. I have had interviews as early as Jan 3rd. Just don't go for too long Missing a couple of days with the fam versus matching in ortho (because you missed that one interview..) is something to consider.. plus, you can always visit the family after february or after the match.. Something to consider

Hey just wondering when the latest residency interviews usually are in December and the earliest in January. I'm planning on going to London to see some family for Christmas, and was going to buy my ticket soon. Thanks.

Wouldn't it be funny if you couldn't make it to your interview because of an Icelandic volcano?!

Last I had before the break was dec 21, first I had after the break was the 5th of Jan or whatever that Monday was

Christmas week is safe. As mentioned before, though, try and pad your interviews to give a couple of days' buffer in case coming home becomes a problem.