All of my interviews were very relaxed. They just want to get to know you. If your interviews are like mine, you will probably talk about faculty from the school you attend, why you want to work for them, about family (if any), about a research project. Nothing out of left field for me. I think as long as you can hold a decent conversation for 10 minutes and be polite, humble, and interested, you'll be good.
As with medical school interviews, I felt that Ortho residency interviews were to weed out the weirdos.