In reply to GDes:
I have one, only noticed it in the shower one day. I sometimes think my knee twinges, but that might be unrelated and it doesn't really cause me any problems and I run and lift heavy weights (squat/deadlift).
If it doesn't bother you then what's the problem OP? If they burst they can be painful, but the treatment is rest, elevation and painkillers until it eases. If they do cause problems they can be operated on.
Post edited at 11:05