What Are Gel Injections?

Gel injections — known medically as viscosupplementation — use a substance called hyaluronic acid (HA) to supplement the natural fluid that lubricates and cushions your knee. A healthy knee is bathed in fluid rich in hyaluronic acid, which helps the joint glide smoothly and absorb shock. In a knee with osteoarthritis, this fluid breaks down and thins out. Injecting HA (common brand names include Synvisc, Euflexxa, Gel-One, Orthovisc, and Supartz) helps restore lubrication, reduce pain, and improve mobility. It is thought to work both by mechanically cushioning the joint and by calming inflammation within it.

Who Might Benefit

Gel injections are used specifically for knee osteoarthritis, most often when pain persists despite activity modification, weight management, physical therapy, and anti-inflammatory medication — or when those medications are not well tolerated. They are not a cure for arthritis and do not rebuild lost cartilage; the goal is to reduce pain and improve function, which for many patients can delay or avoid the need for more invasive treatment.

Dr. Pettit will confirm the diagnosis with an exam and X-rays and discuss whether gel injections are a good fit for your knee and your goals.

What to Expect During the Procedure

Depending on the product Dr. Pettit selects, viscosupplementation is given either as a single injection or as a series of 1–3 injections spaced about a week apart. The procedure is done in the office and takes only a few minutes. The skin is cleaned and numbed, and if there is excess fluid in the knee it may be drained first. Dr. Pettit may use ultrasound guidance to ensure the gel is placed accurately within the joint. Most patients feel only brief pressure or a pinch.

After Your Injection

• Rest the knee and avoid strenuous or high-impact activity (running, prolonged standing, heavy lifting) for about 48 hours.
• Some mild soreness, warmth, or swelling at the knee is normal for a day or two. Unlike PRP, you may ice the knee and take your usual pain reliever for comfort.
• Return to normal daily walking and gentle activity right away as tolerated.
• It often takes 2–4 weeks to feel the full benefit — relief builds gradually rather than immediately.
• When it works, pain relief commonly lasts up to about 6 months, and the injection series can be repeated as directed.

Risks

Gel injections have an excellent safety record. Because HA is not absorbed into the bloodstream in a meaningful way, there are no systemic side effects. The most common issue is temporary pain, swelling, or warmth at the injection site. A local inflammatory (“pseudoseptic”) reaction is uncommon and settles on its own. As with any injection, infection is rare.

Insurance & Cost

Viscosupplementation is frequently covered by insurance for knee osteoarthritis, typically once arthritis is confirmed on X-ray and after a trial of conservative treatment. Coverage rules, the approved product, and the number of injections vary by plan. Our office will verify your benefits and obtain any required prior authorization before scheduling your injection so there are no surprises.