Hey bro, thanks for your service. Too bad you had to leave parts of your knee "in country."
Do some web research on prolotherapy. Surgeons aren't into it because it cuts (no pun) into their pocketbook. They make big bucks for replacing knees, and are not really interested in fixing your problem any other way.
Your surgeon will tell you prolotherapy will do you no good, but then again why should he??? He's in the business of selling metal knees, not fixing you with a proceedure that is a fraction of the cost. Anything non-surgical is a threat to surgeons.
What if the injections worked??? You could retain your original parts (which are always better)and stand an excellent possibly of riding pain free. Once cartilage regeneration has taken place, it will stay there for good.
I don't know how long a metal knee will last with regular cycling, but it will never be as good as your original knee. I'm sure you are experiencing some intense pain, and that's when patients usually want to get their knees replaced.
There have been some real miracle stories about prolotherapy, even with patients who have no cartilage, and are bone on bone. It sounds too good to be true, but often, truth is stranger than fiction. Before you go under general anesthesia and have your knee cut out, why not pray for a miracle and get the injections???
Here are a few links:http://www.prolotherapy-los-angeles.com/http://www.getprolo.com/
If the injections fail, they fail, but at least you tried. Getting your knee cut out can be done at any time.