I ruptured a ligament that bled into the knee over night in the 80's skateboarding, the bike was my physio, and got me hooked. More recently, I dislocated my kneecap skateboarding at 36 years old. It tore a nice hole in the back of the kneecap, and the lower portion of the joint. (it's a hole about the size of the nail on my pinkie finger). After the arthroscopic removal of the bone fragments, I was using a cane for six months before I could even get on the bike. It was a year before I could fully compress my knee without feeling like my kneecap was going to shoot across the room. I now have very little lateral stability and am terrified of dancing as one wrong move could drop me to the floor. They still want to "cork" the holes with donor bone and cartilage, but my knee guy says so few people have had that surgery there is no long term data on the after effects. He wants me to wait until I can barley walk. Yes they are all different. It's gonna take time though. Spin spin spin.