What is knee gel injection (viscosupplementation)?
Knee gel injections are intra-articular hyaluronic acid (HA) treatments designed to supplement the joint’s natural synovial fluid, which thins with osteoarthritis. HA is a viscoelastic molecule that improves lubrication and shock absorption inside the knee, helping some people move with less pain.
In the United States, HA knee injections are FDA-cleared as medical devices to treat pain from knee osteoarthritis in patients who haven’t had adequate relief from conservative care. Current clearance applies to the knee only; use in other joints is off-label.
Clinical guidance varies: some guidelines are cautious about routine use because trial results are mixed, while others allow shared decision-making based on individual response, comorbidities, and goals. In practice, viscosupplementation is often considered after exercise therapy, weight management, oral/topical analgesics, bracing, and physical therapy.
Most people start with first-line care for knee osteoarthritis: targeted exercise and physical therapy, weight management, activity modification, heat/ice, oral or topical NSAIDs, and bracing as needed. If symptoms persist despite these measures, your clinician may discuss injections such as corticosteroids, platelet-rich plasma (PRP), or hyaluronic acid (viscosupplementation) as next-step options based on your goals and health profile. 
