Rabbit: I'm missing ACLs in both knees. I'm as recovered as I'm going to be - the injuries were some years ago, I rehabbed and continue to work out. I wear only neoprene knee warmer/supports. I've worked well over 100 games each of the last ten years - a majority of them plate. From my experience and observing current athletes with similar injuries, it'll take upwards of a year to get your muscles toned to do the work of the ACL, and to get the confidence in your knee and body to do umpire activities. Take it slow on the field, but work your butt off on the prescribed rehab exercises. Keep working, plan on a comeback. Good luck. FYI - Now, most likely due to the ACL and associated injuries and cartilage tear/wear, I'm looking at dual knee replacements - SOON. But, I'm still planning on working ball games.