It depends on whether you think you'll have time to read it at home. Personally, on my trauma rotation, I typically got home well after 8:00pm everynight with many nights closer to 10:00 pm and occasionally later. I didn't have anytime to read it while on service except for a few minutes here and there during the day in which case, I used the resident library copy. Most of the time was between seeing ER patients trying to figure out what to do with them. So my "brand new" books collected dust at home and was a waste of money. The books that I got the most out of at home was Campbell's, OKU, Hoppenfeld, and Miller's Review. Now if you actually have time to read on trauma, it may be worth it to have R&G or Skeletal trauma at home.
As an intern, I would recommend reading a general orthopedic overview book if you can and the basic science book. Now, the basic science book is a snore fest, but important and it will also make a huge difference on your OITE scores if you have any retention.