Your knee isn't just a hingeit's a living, dynamic system built to move. Inside every healthy knee is synovial fluid, the natural lubricant that reduces friction, delivers nutrients to the cartilage, Joint fluid fills the small space between the ends of bones and acts like a natural lubricant. The synovial membrane creates this thick, silky fluid using long molecules that hold water and give it a Gel Knee Injections for Pain Relief What to Expect Oak Brook Medical Is Knee Gel Injection the Right Solution for You?