The VAST majority of interveiws are incredibly friendly. These people are trying to decide if you're the one they want to see in the O.R., getting the patient ready, when they have to come in in the middle of the night. It is not a test, just a conversation.
Unfortunately, some people are terrible conversationalists after spending an entire day interviewing applicants, so they may resort to oddities to get you talking.
More generally, don't have canned answers or questions, but be ready to talk in depth about:
1. any research you have done--talk about the science, NOT how much work you did or how amazing you were to come up with the project
2. the city/region where the program is
3. unique aspects of the program organization
4. Your mentors/letter writers and your work with them. Remember that academic ortho is a relatively small world, and many know each other. If your mentors were important in your educational development, let interviewers know how and why, as well as why you think the interviewing program seems like it could offer similar or improved experiences.
Your honest enthusiasm is your best friend in interviews: enthusiasm for orthopaedics, enthusiasm for your research, enthusiasm for medicine in general.
Whatever you do, NEVER criticize people or places if you can at all avoid it. If you speak with respect and admiration for the people you have already worked with, your interviewers can expect that you will ultimately speak with respect and admiration for whatever residency program you complete.
my $0.02
