Sorry .Your situation scream tick born illness.Ironicly they are many.My knees finally are not swolled up any more.I can not include what I included to someone else before.Try to see in this forum other post that I have had writen before this one.
You have to understand that the knee swollen screams spirochete..there are strains that loves the knees so badly as they are strains that love the brain and cause neuro issues.You need to educate yourself.Only sombody with a microscope -dark field can see exactly what is going on with your knee fluids.If your immune system is strong than you might not find it in the blood but that does not mean you do not have it.
So a specialist seeing your knee fluid and testing it for lyme can help you ...as well as it might be other tick borne illness in there.Ironicly it is never alone......
The cronic inflamation is caused by a cronic infection...and this seems your case.Hope you do not end up on the controversy of denials of the disease and many give up ...only the ones that do the homework find the truth and save them self....do not exspect regular doctor to help you ..this are the last ones that I will waste my time.THEY wasted 20 years of my life.