Fluid is normally found in joints such as knees, hips, and elbows. When too much fluid builds up around a joint, it's called joint effusion. It may cause the joint to look swollen.

Many things can cause fluid buildup in a joint. Examples include conditions like osteoarthritis, rheumatoid arthritis, or gout. It may also happen because of an infection or an injury.

Home care may help relieve pain and swelling. In some cases, a doctor may prescribe medicine or drain the fluid from the joint. Sometimes surgery is needed.