Your body makes hyaluronic acid. It's a natural part of the fluid that helps lubricate your joints and keeps them working smoothly. It also acts like a shock absorber. It keeps your bones from bearing the full force of impact when you walk.
When you have osteoarthritis (OA), the hyaluronic acid in the affected joint thins. Hyaluronic acid injections add to your body's natural supply. You may hear your doctor refer to these injections as "viscosupplementation," which literally means they help the fluid in your joints.
Should You Try Hyaluronic Acid Injections?
Doctors can't predict who will benefit from hyaluronic acid injections. But many doctors give them to people with knee OA whose symptoms don’t get better with painkillers or non-drug treatments such as heat or ice.
Hyaluronic injections are also often tried by people who can't take painkillers like Advil or Motrin (ibuprofen), Aleve (naproxen sodium), or Tylenol (acetaminophen), or can't have (or aren't ready for) total knee replacement surgery.
How Effective Are Hyaluronic Acid Injections for Osteoarthritis?
Studies show hyaluronic acid injections may work better than painkillers for some people with OA. Other studies have shown they also may work as well as corticosteroid knee injections.
Hyaluronic acid injections seem to work better in some people than others. They may be less effective in older adults and people with severe OA.
Getting a Hyaluronic Acid Injection: What to Expect
Five brands of hyaluronic acid are approved for knee OA:
- Synvisc, Synvisc-One
Depending on which type your doctor uses, you may get a single shot. Or you'll get three to five injections spaced a week apart.
The injection is given the same way for all types. First, the doctor cleans the area. If your knee is swollen with excess fluid, your doctor may inject a local painkiller, then insert a needle into the joint to withdraw excess fluid. With the same needle still in place, the doctor can usually inject the hyaluronic acid into the knee joint.
After an injection, you shouldn't do hard weight-bearing activity for one or two days. Otherwise, you should be able to resume normal activities.
Most insurance companies cover hyaluronic acid injections.
The most common short-term side effects are minor pain at the injection site and minor buildup of joint fluid. These get better within a few days.
Infrequently the injected joint may flare up with increased inflammation.