Gel injections (also called viscosupplementation) are used to treat joint pain from arthritis, especially in the knee. The gel acts as a lubricant and shock absorber inside the joint, helping reduce friction, DIY Personal Lubricant Going Zero Waste A gel injection for the knee helps improve joint lubrication when natural synovial fluid becomes thinner or less effective, which often happens with arthritis., This gel acts as a cushion and Corticosteroid vs. Gel Injections for Joint Pain Which is right ? City Orthopaedics & Sports Medicine: Shoulder, Knee, & Hip Surgeon