Damaged leg on 3-year-old male cat -- now it "snaps" when he walks.

My cat jumped from a two story window about 8 months ago and damaged his left rear leg (was limping badly). I immediately took him to the vet to have it x-rayed and there was no break or crack, so the vet said to simply keep him somewhat contained for a few weeks to let it heal. I kept him in two very large dog crates zip-tied together until he stopped limping -- about 2 weeks.

Since then -- especially in the morning or after he's been sleeping -- the hind leg slightly "snaps" when he walks. The vet said that this would probably correct itself over a bit of time, but it's still there and hasn't changed.There is no clicking sound -- it just looks like something is "snapping" into the place every time he uses that leg when walking. His activity level is normal - he is still very active, loves to run, jump, etc.

I'm worried that this could cause long-term problems in the future (arthritis), etc., and it simply doesn't look right and worries me. 

Thanks for your ideas/opinions!

It might be worth a return visit to your vet, but unless there is something he can treat the future is what it is.  I've had something that sounds similar after joint injuries, and mostly with time they have sorted themselves out though it took many years for the ankle I partially pulled the tendon off the bone to fix itself.