Joint effusion is more commonly known as water on the joint. Although water on the knee is most common, hip joint effusion can also happen.
All mobile joints, including the hip joint, contain a small amount of synovial fluid. This substance helps lubricate the cartilage surfaces so they move smoothly, and helps nourish and protect the cartilage in the joint.
Too Much Fluid
Hip joint effusion is when the joint has so much synovial fluid that you can either see it or feel it as a tense swelling or pain. According to the University of Washington, Department of Orthopaedics and Sports Medicine, a visible or detectable swelling of a joint is never normal.
Many conditions can cause hip joint effusion, including arthritis, trauma (the fluid may also include blood), and infection (the fluid may be pus).
X-rays can detect effusions; however, to determine if the joint contains blood or pus requires a synovial fluid analysis.
According to the University of Washington, Department of Orthopaedics and Sports Medicine, treatments for hip joint effusion depend on the cause of the fluid accumulation. Antibiotics may be needed for infections or anti-inflammatory drugs to reduce the effects of trauma. Or fluid may need to be removed from the joint using a procedure called aspiration, where a needle is inserted to draw out the fluid. Sometimes, time is just required for the body to reabsorb the fluid from the joint.