Chronic inflammation causes a build-up of fluid in the knees. Cysts form in the back of the knee, fill with excess fluid and when it bursts causes extreme pain and, in my case, inability to put weight on my leg. Cyst fluid goes up and down the leg causing pain until the body absorbs it. Doctor said that once inflammation is controlled they will stop forming. I just started Humira last Saturday after two years of other medications that did not work well. Anyone else experience Baker’s Cysts? Love to hear your stories.