There are articles on either the ACGME or NBME website looking at % matched by step 1 score. 231-240 matches in ortho at an 85% clip according to 2009 data. Given that, certainly you don't want to fall in the 15%. You truly need to embrace the advice above: your performance on rotations will be the deciding factor.
Things you can do:
1. Network: Spend some time trying to get to know the residents at your program, through morning conferences or grand rounds or through the projects you're trying to get involved with. Showing enthusiasm for Ortho is generally well regarded, and hopefully you'll be able to learn some things applicable for rotations. The young residents in your program have just gone through this process and are generally very receptive to seing someone expend effort, as they most likely came from a situation like yours (which isn't really a situation, more like baseline). Invest some time in them and they're likely to reciprocate.
2. Be prepared for the rotations: get a fracture handbook & start familiarizing yourself with the pages. If there's a fracture conference, see if you can go before your 3rd year rotations start, which isn't always possible. Find some x-rays and make yourself go through the process of "what would I say if I was asked to read this film". I can't tell you how many times I saw students not prepared, hadn't heard of the handbook, didn't know their anatomy, and didn't know how to functionally apply the anatomy (physical exam).
3. Find a faculty mentor on campus. Critical. Orthogate has drawbacks. You don't meet the people. You have no context to evaluate what people say.
4. Prepare to work hard & tell yourself it will be worth it. Best advice I was ever given in preparation for rotations: get there early, stay late, don't complain. Being positive affects the way that residents view you. No one wants to help out a complainer.
5. Don't throw away the idea of a research year. I think this is understated on orthogate. If you're really, really concerned about your potential app (which from your stats - I don't think you should be, just remember that lots of people don't match with a 260), I think its better to spend the year before trying to match. I am biased because that's what I did and it worked for me. However, consider the future interview possibilities: "I recognised some shortcomings in my application and I wanted to address them proactively; I'm serious about this as a career" vs "I don't know whay I didn't match and this is what I tried to do to recover". That doesn't even discuss the difficult nature of trying to improve your application as a surgical intern the next year.
