What did they do?

Well, I'm not the best person to explain this.
However, the following website gives a brilliant breakdown of what happened.
Some of the detail about the operation may be wrong, but the general information as to where the graft was taken from and where it was attached is all correct I think.

I haven't had a go on those continuous motion machines either.

http://www.arthroscopy.com/sp05018.htm
http://www.arthroscopy.com/sp05025.htm

It's all very cool. I know that the screws I had inserted are made out of stainless steel rather than being biodegradable (I had to ask at the following appointment a week after the op). I was also given the product stickers of the screws in case there is a product recall. I've been told that they shouldn't set off any airport alarms as they are quite deep.

So, that was the op. Obviously I didn't remember much about it!