There is strong biologic plausibility that one should always aspirate an effusion before injecting hyaluronic acid. Even a mildly inflammatory effusion will have an excess of white cells. White cells produce hyaluronidase. Hyaluronidase catalyzes the degradation of hyaluronic acid and renders it ina...

Yes, I routinely aspirate an OA knee effusion when one is there just before injecting HA. Most all of my knee interventions are performed under ultrasound, even if informally, to minimize pain and maximize fluid identification, so it is easy to aspirate and then change the syringe onto the same need...