Knee aspiration, also known as arthrocentesis, is a simple in-office procedure used when swelling and stiffness limit mobility. Fluid can collect inside the joint from arthritis, inflammation, or injury, creating pressure and discomfort. By carefully draining this fluid, aspiration reduces pain, relieves stiffness, and improves mobility. Sometimes, the procedure is followed by a cortisone (steroid) or gel injection to calm inflammation or restore lubrication for longer-lasting relief. #kneepainr