(ĐTĐ) - Exercise and other physical activity is important when you have osteoarthritis (OA). But joint pain and stiffness in a knee can make it difficult just to walk, even with medication and other treatments. If that sounds like your situation, or if you can’t take oral arthritis medicine, hyaluronic acid injections may help.
Also called visco supplements, these injections add to the joint’s natural supply of hyaluronic acid, a part of the joint fluid that helps lubricate joints and keep them working smoothly. Hyaluronic acid is also a shock absorber that keeps your bones from bearing the full force of impact when you walk.
When you have osteoarthritis, the concentration of hyaluronic acid lessens. Hyaluronic acid injections are given to supplement the joint area. Experts aren’t completely sure how the injections work, however, because the additional hyaluronic acid stays in the joint for only a matter of hours or days.
Getting a Hyaluronic Acid Injection: What to Expect
Five different brands of hyaluronic acid are available and approved for knee OA:
- Synvisc, Synvisc-One
Depending on which type your doctor uses, you’ll get a single shot or three to five injections spaced a week apart.
The injection procedure is the same for all types. First, the doctor cleans the area. If your knee is swollen with excess fluid, your doctor may inject a local anesthetic to reduce pain, then insert a needle into the joint to withdraw excess fluid. The doctor can usually use the same needle still in place to inject a syringe with the hyaluronic acid preparation into the knee joint.
After an injection, you shouldn’t do any excessive weight-bearing activity for one or two days. Otherwise, you should be able to resume normal activities.
How Effective Are Hyaluronic Acid Injections for Osteoarthritis?
Hyaluronic acid injections seem to work better in some people than others. They may be less effective in elderly people and people with severe OA.
The results of studies on their effectiveness as an osteoarthritis treatment have been mixed. A 2002 study published in Rheumatology found that in the short term, a shot of hyaluronic acid didn't reduce joint pain any better than an injection of salt water. An analysis of seven studies published in the Journal of Family Practice in 2006 concluded that the benefits -- if any -- were slight.
But another analysis of 20 studies from 2004 found that hyaluronic acid injections did lessen pain and increase knee function in people with OA. And an earlier analysis -- of eight clinical trials involving 971 people -- found that people treated with hyaluronic acid did better than those treated with placebo, both at the end of their treatment and six months later.
More recent research has found that the injections relieved pain about as well as nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, or steroid injection. Some studies show that pain relief lasts up to six months or a year.
Hyaluronic Acid Injections for Osteoarthritis: What Are the Risks?
So far, there appear to be no long-term side effects and few short-term side effects from this treatment. The most common side effects in studies were minor pain at the injection site and effusions (build-up of joint fluid), which got better within a few days. Doctors don’t know whether the medication or the injections caused these reactions.
Should You Try Hyaluronic Acid Injections?
Doctors can’t predict yet who will benefit from hyaluronic acid injections. But many doctors consider them for people with significant knee OA symptoms that have not responded to other treatments, and for those who can’t take oral medications or have total knee replacement surgery.
Talk to your doctor to discuss whether the injections might help you. Most insurance companies cover hyaluronic acid injections.