For ortho, I don't think how famous the general surgeon is matters all that much. Most orthopods probably won't know them. If you're getting a letter of reccomendation from a general surgeon, I think that you should just make sure it's a very good letter. I didn't have any letters of reccomendation from non-orthopaedic surgeons. But, some programs may require or ask for it. My belief/understanding is that programs prefer letters from orthopods because it is reflective of how you did in our field. I mean, if you get a great letter from an internal medicine attending, that's great...but, whoopdeedo, some surgeons think medicine docs just sit on their asses all day. The ortho work ethic is different, and it's easier for us to relate to or believe a letter of reccomendation when it comes from our peers.
Now the "big name" versus less famous ortho letter of reccomendation is a different story, and has been discussed in previous posts.