Help...torn, or......??

I had ACL reconctruction last June. All in all, it went well. Last karate class, we were doing some hard sparring. I threw a kick, and my opponent backed out of range. I felt a little twinge in the knee. Not bad, but enough to realize I had over extended it. ( Was a front thrust kick ). Now, I hear a little clicking / grinding in there. Doesn't hurt.....but ?? Looking at some of the threads that have been on, you can tear the ACL second time around,and not even know it.
Any advise would be appreciated. Im still working and fully mobile, but curious as to what may have happened.

anybody??????

ttt

ttt