Any problems with it since then?
No problems with it really. Sometimes if it is really cold outside, it can get a little bit sore & stiff. I wear a neoprene brace on it when I ski, but I haven't gone in quite some time now.
Your hubby should be fine. I knew two guys, one had it all removed from a knee, the other had most of it removed. One was an avid backpacker, the other an avid skier.
They both said to train regularly, and keep the quads strong. Cycling is really good if you are recovering from surgery, though I don't ride too much.