I like books, so I've read/used alot of different texts, but for me by and far the most useful for rotations was Netter's Orthopaedic Anatomy. I would say that 95% of the questions I was pimped were in that book. I'm sure people's experiences differ, but from my experience the things that attendings really expect you to know (and are impressed by) are anatomy (including nerve distributions). It also has physical exam and pathology pearls that are useful.
IF you have advance knowledge of what cases you are doing, hoppenfield's is great because you know what to expect during the dissection. I was always annoyed when I'd be holding some retractor from practically behind the anesthesiologist and then be asked what something was. I wanted to say: "I can barely see the damn field!" but if I had a chance to bone up on the approach I could at least make a good guess. Also, if you know what is coming than you can take a look at Campbell's, Rockwood and Green, Skeletal Trauma, etc. Of course, it impossible to read Hoppenfield or any of the aforementioned texts and remember it all unless you are some kind of mutant super-human.
There is a new book: Netter's Orthopaedics. I have it and it looks pretty good, perhaps even worth a cover-to-cover read during the rotation (it's not too big). However, it came out after I was through rotating so I have only took a cursory look at it.
My main point is that I believe anatomy trumps everything else in terms of importance for the medical student on a surgical (orthopaedic) rotation. Beyond that, you need to predict the conditions that you will be presented with most commonly on whatever service you are on (trauma, joints, peds, etc...) and read about those in a major reference book specific to that specialty. All the ortho resident lounges I've seen have copies of these lying around so you can peruse them there if you don't have a $3000 start-up fund lying around for your personal ortho library. Waiting for OR turnover has always been my most efficient reading time!
