Why are knee injuries so devastating?!

The knees are the weakest area of your body. They are made of mostly tendons and ligaments. Unlike muscles and bone, these structures have little to no blood flow. This makes healing very difficult. Once healed, the knees are never as good as new. The ability to run and cut is greatly reduced. However, there are bio firms trying to grow tendons from blood vessels. blood vessels that we are born with turn into tendons when we don't need them for fetal growth and development. If these labs can replicate that transformation, they will be rich beyond their dreams, and athletes who otherwise would have to hang up the cleats would get another shot.

I can tell you that it does not even take a severe injury like the ones that you described for your life to be devastated. I have severe arthritis in both my knees and I have been thru 10 knee surgeries so far to help with the pain.
I was told when i was 16 that i had this condition in both my knees. While my younger years where ok now that I am 38 my life is totally changed. I am in pain all the time, I can hardly walk the dog down the street and back. I have had to give up most of the sports that I loved to do and I am clinging to the only sport that I have left (horseback). The pain is so bad that I am not even able to get up out of a chair while holding my granddaughter.At night things do not get any better if i move wrong i wake up close to tears from the pain. It has ruined my life and my knees are what rules what I can and cant do now.

the knee is the largest most complicated joint in the body. a lot can go wrong and when one thing goes wrong another may. also you much realise that the knee cap can make things worse. look up a picture of a knee joint sometime and you'll see what i mean.