Several varieties of hyaluronan injections, which a doctor injects directly into the joint to treat mild-to-average knee osteoarthritis, contain processed rooster combs, states WebMD. Injection varieties include 1 percent sodium hyaluronate, hylan G-F20, and high-molecular-weight hyaluronan. Use of most varieties is contraindicated in patients allergic to poultry or eggs.
Hyaluronan is an essential substance in normal joint fluid that functions like a lubricant and shock absorber to keep the joint working properly. The high viscosity of hyaluronan allows the cartilage surfaces of the bones to glide smoothly, which helps reduce osteoarthritis knee pain, allowing increased mobility, explains WebMD. Possible side effects of the injections, called viscosupplementation, include joint inflammation. Patients with joint or skin infections cannot receive viscosupplementation.