Stiff and sore joints are a reality for most of us as we get older. Normally, our body secretes natural lubricants that reduce friction between the joint surfaces. Gel injections for knee osteoarthritis contain hyaluronic acid which can provide relief by improving joint lubrication. 

Knee osteoarthritis increases friction in the joint causing the protective layers of cartilage on joint surfaces to slowly break down. Treatments aimed at decreasing joint friction are also known as viscosupplementation. According to experts¹², if you’ve tried exercising, dietary changes, and other painkilling drugs with no success, this treatment could be for you.

How Do Gel Injections for Knee Arthritis Work?

The active ingredient found in gel injections for knee arthritis is hyaluronic acid. Hyaluronic acid is produced naturally by our bodies. It is a key component of the lubricating synovial fluid found within many of our joints. In knees with osteoarthritis, the quality of hyaluronic acid decreases over time¹. Low-quality hyaluronic acid affects the consistency of synovial fluid, reducing its lubricating and shock absorption qualities. 

The main benefit of injecting hyaluronic acid into joints is greater lubrication. However, there are several other ways in which it may improve joint function¹:

• Hyaluronic acid is “anti-oxidative”. This means it can combat the build-up of harmful substances in the knee joint.

• Hyaluronic acid may increase the knee joint’s ability to regenerate cartilage. 

• Hyaluronic acid may reduce inflammation within the joint, relieving stiffness and pain from arthritis.

The treatment procedure for gel injections for knee arthritis varies depending on the type of product being used by your doctor. SynVisc One, MonoVisc, and Durolane involve just one injection, while others require as many as five weekly injections in a row. The injections themselves are fairly quick as the injection solution and site do not need much preparation. As this is an outpatient procedure, you are free to leave the clinic after the procedure is complete.

How Much Pain Relief Can Gel Injections for Knee Arthritis Provide?

Research into hyaluronic acid injections is much more established than that of platelet-rich plasma injections and stem cell therapy. However, much of it is sponsored by industry and the methods used differ greatly between studies. Despite this, the body of research to-date shows that hyaluronic acid can provide 4-24% greater pain relief compared to a placebo saline injection⁵ at 1-4 weeks post-injection.

At 5-13 weeks, benefits of hyaluronic acid injections may be even greater. Some studies have found up to a 43% benefit in pain reduction relative to placebo injections⁵. One recent study showed that patients who received gel injections for knee osteoarthritis were able to delay their knee surgery by 8.7 months⁶ on average.

Am I a Good Candidate?

Like any treatment for knee arthritis, some individuals respond better than others. Approximately 50% of patients have a noticeable improvement in their knee function and pain after receiving gel injections³.  Much research has been done to understand the characteristics of people who consistently respond well to gel injections for knee arthritis⁴. 

If you are considering getting gel injections for knee arthritis, take a look at the candidacy checklist. This tool is based on a 2011 study⁴ reviewing past scientific research on the effect of hyaluronic injections on those with knee osteoarthritis. The better candidate you are the more likely you are to have a positive experience. If you want to learn more or feel like this treatment could be for you, discuss your specific situation with your doctor.  

Combination Treatments

Gel Injections and Knee Bracing

Gel injections may be even more effective when combined with knee bracing. A study in 2015 followed 207 patients after they had received a series of 3 hyaluronic acid injections⁷. During the 6-month follow up period,  half of the patients were equipped with a medial uni-compartment offloader knee brace (learn more about offloader knee braces).

In the follow-up, patients with moderate (grade III) knee arthritis saw improvements of 40% on average in their pain score. Those with mild knee arthritis (grade II) saw a 20% improvement on average. The addition of a knee brace resulted in better outcomes for patients with severe (grade III – IV) knee arthritis.

The Kellgren Lawrence grading system for osteoarthritis is a common scale of arthritis severity. For individuals with the most severe grades, injections and bracing as a combined treatment had the most obvious improvements in symptoms.

These results are encouraging as gel injections in isolation appear to be less effective for those with severe knee arthritis¹. A similar synergy may also exist with knee bracing and stem cell therapy.

• How to Choose the Best Knee Brace for Arthritis
• Knee Braces for Osteoarthritis – An Alternative to Knee Surgery
• Top Five Offloader Knee Braces

Gel Injections and Stem Cell Therapy

Stem cell therapy is an extremely exciting area of research that may one day change how knee osteoarthritis is treated. Currently, patient outcomes from stem cell therapy are inconsistent with respect to re-growth of healthy knee cartilage. Hyaluronic acid may one day be part of the solution.

The combination of hyaluronic acid and stem cell therapies may be more effective than either treatment alone. Some studies have shown that combined therapies have increased the chance of rebuilding cartilage⁸. Hyaluronic acid appears to enhance the capacity of stem cells to form cartilage, allowing the treatment to become more effective. Clinical trials are currently underway for this combination therapy⁹.

Treatment Cost

The estimated average cost for the popular Synvisc-One injection is $1012.00 in the United States. Another popular product, Durlolane, costs on average $894.00. Prices fluctuate greatly depending on the number of injections and administration time required. Depending on your insurance policy, much of these costs could be covered.

Side Effects & Risks

Gel injections for knee arthritis are well tolerated by the majority of patients. The most common side-effects are localized joint swelling and stiffness immediately after the injection¹⁰. After 1-2 days these issues are typically resolved.

In rare cases, gel injections can induce a pseudoseptic inflammatory reaction¹¹, resulting in symptoms including fever and low blood pressure. If left untreated, this can cause severe joint pain and inflammation to linger long after the initial injection(s).

Additional Resources

• Manage Your Knee Arthritis Without Surgery or Drugs
• Knee Arthritis Treatment Guide