Had a Injury Playing Football

Hey Last year I had a knee injury to my Patella tendon while playing football. I finally after going to several doctors after having a MRI they said it had a slight tear and that my kneecap was out of line and it also Said I had a loss of articular cartldige... Ok before this injury I had No cracking or poppin in my knee what so ever and Now when I extend my leg out or squat its bad cracking and poppin right down the center of the kneecap and it sounds like two grinders coming together and the doctor told me that it was just arthritus and nothing could be done.. Well its not giving me too bad of trouble right now its just that aggervating grinding is getting to me.. Its so bad when I extend my leg ppl across a room can hear it poppin and grinding.... I think its bone on bone already down my kneecap.. Can Anything be done for this??? And If so what do I need to have done?? The doc told me to come back and he wouls scope it or something.. Do I need to have this done or should I advoid it?? What bothers me is if i coutinue to exercise and stuff and that knee cracking and poppin like it is im afraid ill mess it up to the point to where it will be really bad.. What Should I Do??? Any advice would be great.... Im 24 now and I dont know what to do weather I should try to get this problem fixed with orthoscopic surgery or let it go for long as I can..