gemfyre | Bizarre question - must be research for a story

So, I wrote a story, a bit of fanfic. Some of you may have read it. In my mind is forming a sequel of sorts, but I want my facts straight first.

So. We have the scenario. 15 year old girl, promising ballet dancer, has a psycho wail on her legs with a sledgehammer. Afterwards, for about 3 weeks, she's kept drugged up on painkillers and sedatives, probably gets some minimal topical care for open wounds. But the broken bones - they fuse back where ever they are after the smashing.

Okay, so my questions.
1. Is this survivable? - I'm pretty confident it's a yes. She'd possibly die of shock if it wasn't for being drugged up to the eyeballs. She's escaped things like infections and septaceamia.
2. How would the legs look?
3. Would she be able to use the legs again? Would she limp? Have a cane? Walk on crutches? Or be fully wheelchair bound?

Maybe someone is a doctor or knows a doctor that would know what would result from these kinds of injuries if left untreated (I'd be guessing that if treated right away, after weeks of traction and casts, then months and months of physiotherapy, she might be able to walk again at least - but of course, she's not rescued for about 3 weeks, is this enough time for bone and muscle to fuse and heal back in all the wrong places?)

It's a pretty gory scenario really. But the follow in is pretty inspirational, for me at least.