A lubricating substance commonly used for knee injections.
Hyaluronic acid injections may provide relief for some weeks or months in patients with osteoarthritis of the knee. The material is generally derived from the red 'combs' of roosters or chickens, although sometimes it is derived from bacteria.
Appropriate Use Criteria for Hyaluronic Acid in the Treatment of Knee Osteoarthritis in the United States. Bhadra AK, Altman R, Dasa V, Myrick K, Rosen J, Vad V, Vitanzo P Jr., Bruno M, Kleiner H and Just C. Cartilage. 2017 Jul; 8(3): 234–254.