Knee effusion
Fluid in the knee, also known as knee effusion, is a common issue that occurs when excess fluid accumulates in the knee joint. This can result from intense physical activity, such as running or sports, but can also be caused by underlying conditions like osteoarthritis, rheumatoid arthritis, or a knee injury, such as a meniscus or ligament tear. When the knee becomes overloaded or damaged, the body responds by producing extra fluid, which can lead to swelling, stiffness, and pain. This may limit knee mobility and make daily activities more difficult.