Nisha had a very bad sprain when she was younger. The vet did x-rays to make sure (you need to do this).
We kept her crated, and gave her a TON of bones/kongs. It may not be the healthiest option, but it worked! We took her potty on a leash so she couldn't run around. Also, we did
a lot of training; mental stimulation can really wear them out
It took a LONG time to completely heal; just b/c she doesn't limp doesn't mean she is better. You have to be very careful when you "think" she is better. She may re-injure it if she plays too rough. No jumping, or crazy playing; if she hasn't limped at all in a month, then you are probably safe.
Good luck!