I agree with the books mentioned above. I had two weeks off between 3rd and 4th year and read Delahay & Wiesel's Essentials of Orthopaedic Surgery cover to cover. It is a little old (last edition was in the mid 90's, i think), but give a basic overview of ortho. it is written on the med student level so I though it was perfect introduction. It is a quick read, could easily do in a few days, i spread it out over two weeks as I was on vacation.
during rotations, i used both Hoppenfelds (PE & atlas) and always had the Netter Ortho Atlas in my white coat pocket. I didn't do any trauma so didn't use any trauma handbooks.