Some side effects (also called reactions) may occur with Hymovis treatment. Symptoms such as knee pain, inflammation, reddening, and swelling may appear at the injection site. The occurrence of knee pain after the injection in a clinical study of Hymovis was almost the same for patients receiving saline. Temporary increases in inflammation (redness and swelling) following injections have occurred in some patients with inflammatory joint conditions. If any of these symptoms appear after you receive Hymovis, you should call your doctor.