Eagar torn cartilage and Vietnam draft exemption

So let's take an actual design situation where you'd like to have a lot of modulus and some strength and some toughness. Back in the old days when I injured my knee and tore the cartilage, they'd have to lay your whole knee open in surgery, literally. You have a scar on your leg that's six or seven inches long, and you'd be in a cast for like two or three months and then you'd be on crutches for six months. It was major surgery to go in there and get out that broken cartilage. As a result I now have broken cartilage still after 40-some years in my left knee. I've never had it repaired. Kept me out of Vietnam. They flunked me in the physical because of the torn cartilage. I said, really? Then I found out they could bring me in as an enlisted man. I said, really? Anyway, I still got it. And then I tore the cartilage on my right knee, so now it's symmetric, I can't walk either way.