This is a very political topic. During my interviews, ortho was definitely opening up, and many programs were trying to recruit minorities. Some of the women I interviewed with were bigger, taller and more muscular than I could ever be. Probably kick my butt in arm wrestling... anyways... back to the point.
Having said that, I ran into a lot of very conservative residents and attendings during my away rotations who would make some unnecessary comments about minorities (women, other ethnicities, etc). Not too offensive, but didn't need to hear it, if you know what I mean.
While I think everybody deserves the opportunity in a non-hostile environment, no matter where you go I think you might run into it. I doubt many people will directly confront you about your sexuality, but you might still feel the tinge of difference/feeling/attitude. If ortho is your calling I would just go for it and put up with it.
I wouldn't focus on your sexuality too much in your application though. Sexuality is not exactly the topic anybody wants to discuss during the interview. Talk about your passion for orthopaedics and I think you'll be fine. It would also be an opportunity for close-minded residents/attendings to experience first hand that gays/lesbians are indeed like the rest of us.
