My Roxy had both her rear legs done at the same time too! All went well, although after her 6 week check up, it was determined that her one leg didn't stablize. So, we had to have another surgery.
Now she is a NEW girl!
P.S. Go to the 'search' here on yorkietalk.
Type in Luxating Patella
You will find many more threads that go into more detail about LP surgery and recovery. There's lots to read and know about it, this way you can be prepared for the 'long' recovery, exspecially since you have to do it 2x
Best of Luck!