Hyaluronic acid is a lubricating substance commonly used for knee injections in patients with knee arthritis.
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. It forms a gel which is similar to the natural lubricant inside the knee joint.
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.
Viscosupplementation. de Rezende MU and de Campos GC. 2017 Jul; 8(3): 234–254.