Here's an LA Times article from 2003 that mentions the injuries:
http://articles.latimes.com/2003/aug...rts/sp-horse19
I think the confusion is because some accounts right after the race said it was only a sore shoulder.
And a video. The guy who put this one up set it to "Chariots of Fire" but the fall is a little too terrifying from the front angle to be humorous.
http://www.youtube.com/watch?v=ilUEjYf4juQ