Need Some Info Please!

Im a 24 yr old Male and from years of playing football and basketball I was told by a doctor that I dont have much cartlidge left and that ill have severe arthritus down the road and ill need knee replacement eventually.. Does anyone know what options are out there for people with thinning cartlidge? I have been reading about something been done with bone marrow and regrowing cartlidge and also heard something like HGH is used to grow cartlidge back.. If so would it be a good idea to go ahead and starting trying to get something done now to regrow it back?? Or wait until it starts giving me bad problems.. It hurts some after exercise but not enough to where its unbearable.. Any Advice would be great... Thanks!!!