Gel injections for the knee involve a surgeon removing excess fluid from the knee before injecting hyaluronic acid, a gel-like fluid, into the knee. This acid naturally occurs within the synovial fluid that lubricates the joints. It lets the bones glide smoothly over one another, absorbing shocks, notes the AAOS.
The use of gel injections is known as viscosupplementation. Many arthritis patients who have not found success with other nonsurgical treatments have improved through the gel injections. The technique was pioneered in Asia and Europe and then gained approval from the U.S. Food and Drug Administration in 1997. Outcomes are generally most effective for patients in the early stages of arthritis, according to the AAOS.
While hyaluronic acid does not provide instant pain relief, it does, over a longer course of treatment, tend to lessen the pain, as the acid appears to have anti-inflammatory and pain-relieving properties. The effects of the treatment can last for several months. However, gel injections do not reverse the process of arthritis or cause cartilage to regrow. While patients might notice a brief period of pain, swelling and warmth right after the injection, these symptoms generally fade quickly. If these cause discomfort, an ice pack can help ameliorate it, says the AAOS.