I have no idea. It definitely has the same attraction that writing a long, angsty fic starring a one-legged Commodore Norrington had for me. (I need to finish that thing someday.) And it has the same attraction that writing a science fiction story where the Metallica guys had all sorts of scary body-modification surgeries (James Hetfield ended up with bionic arms and legs for instance) had for me. (This is another story I need to finish...someday.)

I don't know why injuries and casts and braces and amputations are hot. They just...make really great fic fodder.