Tore ACL, PCL, MCL, LCL, Medial and Lateral Meniscus transplants (tore so much couldn't repair). If your keeping count, the only thing that i did not tare was my patella ligament.
This was back in 2004, i was 25yrs old.
Was told to never run again, ever, unless someone pointed a gun at me. I followed this advice and only did low impact stuffs until picking up a road bike last year. Did 1200miles my first year, on pace for 2500 this year. I spin at 80-105rpm at all times. Ive found that keeping my rpm in check is critical to preventing knee pain. I also discovered that my cleat position (SPD-SL) needed tweaking with my bad sides having toes a slight couple degrees outward.
I am so excited to be on a road bike, this is really the first time since my wreck that I can push myself physically without pain. Its been the best thing to happen to me in many many years.
Listen to your body man, it will warn you if anything is amiss. Rest days are critical. Also I started with 3-5mile rides, and only increased maybe 10% each month, tops...now i ride 45-55 miles 2x per week.
I know i was 10+ years post surgeries, but thought maybe my input might be of some use to you Sir. Good Luck!
JAG