I broke mine into about 4-5 pieces, and tore my ACL and Meniscus when I was 13 thanks to my dirtbike. Being as young as I was, the ortho decided to stitch it back together in case I grew during the healing process, allowing the bones to grow. Anyways, IIRC, I went into surgery, and came out in a hard cast. I wore it for a few weeks, during which, my leg shrank due to decreased swelling and atrophy. The cast loosened up, went to the ortho for a checkup, where he cut it off, took some X-rays, and recasted it for another several weeks.
I don't remember the exact timeline since it was so many years ago. I remember I was on crutches for a couple weeks or so, and after that, I just walked on it with little trouble.
The worst part about the whole experience, was after I got the 2nd cast cut off. I somehow managed to slip on a puddle of oil about an hour after I left the Dr's office. I fell down, and bent my knee clear back until my heal touched my ass - after not having bent it for months. That hurt. A lot. Even worse than the initial break.
Anyways, expect to be out of commission for a couple months or so.