what is it called to get fluid on top of your kneecap?
Fluid Outside The Knee Joint. When fluid is outside of the actual joint space, and in the soft tissues surrounding the knee, the most common cause is prepatellar bursitis. This condition causes fluid accumulation in the bursa just on top of the kneecap. Usually, the fluid can be felt on top of the kneecap, rather than underneath the kneecap.