I think you are referring to hyaluronic acid injections. Orthopedic surgeons have been using hyaluronic acid injections to help patients with knee arthritis for more than 20 years. Hyaluronic acid is a substance that is present in the human body with highest concentrations in joints and eyes. The substance gives joint fluid more viscosity and acts as a lubricant for the cartilage joint surfaces. Hyaluronic acid is also found in high concentrations in rooster combs and many of the companies that provide hyaluronic acid for medical injections purified rooster comb to extract the substance. Many of the commercially available products are now synthesized in a lab and are not avian or bird based.