Not working your good leg is a mistake! If you simply wait until the bad leg is ready again to work the good leg, whether it is simply staying off of it for a few weeks, or actually undergoing surgery, you're just going to make everything weak.
Go ahead and do what you can with your good leg with unitlateral movements such as 1 legged presses, etc. When the other is ready to go again continue unilateral work only now with both legs, the bad will quickly catch up and you can go back to traditional training.
There's a deeper science and explanation but it basically involves the "rumor" that the body attempts to balance itself (ie left/right arm, or even upper/lower body).
just some thoughts...