Despite how much all of us hate doing gross things like pelvic exams and hemoccult exams, it's part of what you do to get where you want to go. If you blow off some rotations because they "are not important to orthopedics", then it may show through on your application. Don't forget, comments from your rotations go into your Dean's letter. While you may get "Johnny was a good student and worked hard" from your average performance, someone else is getting "one of the best students I have worked with and would be a great asset to any residency program." If you work your ass off people will notice, especially if you figure out how to actually be helpful to your senior resident. It's not about topping the gunner in your group; we're all gunners. It's about paying attention to detail, being knowledgeable about your patients (but not being a show-off), and making your resident's life easier. If your performance on the shelf exam is less than stellar, try to make up for it with your clinical performance.