Did I mention I use a walking stick when walking for more than a block or so?
This is actually fairly recent, and I hate it so very very much indeed...
Last November, in the spring rains (I live in Australia, remember), I had a rather nasty motorbike crash. I may or may not have mentioned it in passing... but I lost a very large chunk of flesh and muscle from one knee, and the doctor said that I was very lucky that I didn't shatter my kneecap. It took them almost an hour to make me agree to let them zot me with a local (I had an irrational fear of needles at that point - I got over it a few weeks back) so they could stitch me up.
Long story short, after much pain, and serving the MELBOURNE BLOODY CUP DAY as a waiter with a sodding walking stick - not an easy thing to do, and it set back the healing process by almost a month - it's all healed up and I have a glorious red-gray scar right across my left knee.
And I still ride my bike.