It means the knee is cracked.
Not sure how old this is, but regardless...usually if there is swelling and they withdraw blood from the knee, it is a result of knee injury. The blood is usually from a broken/cracked bone or torn fibers in cartilidge or ligaments.
Well mostly it's either you broke it or just your knee cracked! I get that a lot, so your in no worry!
The only treatment - is surgery to pin the cracked pieces back together, followed by a prolonged period recuperation.
See a doctor. And DON'T try any home-surgeries.
An old superstition is that a cracked cup means bad luck.
Go to the doctor! Have proper xrays taken and insure that it gets properly set and taken care of.
It means you have a really disgusting knee.
Sudden knee pain with no injury
you have a cold
knee
I assume you mean a cracked rim, if so then DO NOT drive on this. It can lead to catastrophic failure and cause an accident.
Knee on lights = neon lights.