I agree with the above post. I was an ER resident who switched into ortho (just started my ortho residency). You need to be honest with your program. It is the right thing to do, plus it may help you keep your job in case you don't match. Get a letter from the head honcho of your ortho rotation. Also, you have many free days during ER, so go and volunteer in ortho clinic/cases. Make sure there are faculty members as well as residents when you do this. It shows that you're interested. Go to journal club, grand rounds, etc. Offer to do a presentation at grand rounds/weekly lecture. Feel free to PM me with any questions. I've never been happier.