I think what Sawbonz was trying to relate is that the question has a million different answers depending on what exactly you mean. Let's not forget that orthopaedics is divided into 8 or so subspecialties. The "big name" in spine might not be known as well outside that circle. Also, like I said previously, the "big name" on the West Coast may not be as well known on the East.
So, my suggestion would be to redefine the question... e.g. who are the top academic people in Pediatric Orthopaedics on the West Coast (this has a more easily defined answer).
I'm assuming you are wanting to know this because you want "big names" for your letter of recs. Again let me say this is relative. Your best letter of recs will come from people your interviewer knows well. Now, this is not something you will generally know. But, if your interviewer knows the LOR writer and has a high opinion of him, that will transend to you if the letter strongly supports you. If you have a "big name"... and your interviewer thinks this particular guy is an ass... or whatever, than do you think that big name is going to help you? Use your judgement rather than simply look to beef up your LORs with names.
I will give my opinion on LOR advice, others can elaborate.
1) Ortho letters matter most, you will need other letters in your file to meet program requirements. I recommend 1 non-ortho (pref non-surgical ) letter in your packet, supplemented by the rest all ortho. This shows that you can be a part of the "team" and interact well with non-ortho, non-surgical people you will consult.
2) A person who knows YOU well, and will write a strong letter is better than someone who is well known and writes a "this guy worked with the residents on my service... I assume he is an OK guy because I didn't hear any complaints about him and he didn't obviously screw anything up that came to my attention."