that's a bit of a bugger. I did knock a bit off mine in about 1990 in the UK and got it fixed over here (or the fragments taken away), so issue with that since.
I had the bits in a container with me on a subsequent trip to the UK (don't ask me why) - one of those little transparent tubs with bits of bone floating around. I showed it to my aged great aunt and she asked me how many a day I had to take.
Luckily I don't have any great aunts left :).
I would recommend not breaking your patella. It sucks.