Knee Injections for Osteoarthritis: Types, Side Effects, and More

Medically reviewed by William Morrison, MD on March 8, 2017Written by Ann Pietrangelo on March 8, 2017

Overview

Osteoarthritis of the knee can affect anyone, but it usually develops in people over age 50. It’s a progressive disease, meaning it becomes more painful and difficult to move your knee over time.

Your doctor will probably prescribe oral medications and suggest lifestyle modifications before recommending knee injections. Before you turn to surgery, weigh the pros and cons of injections.

Read on to learn about the different types of knee injections and how they work, and find tips for taking care of your knees.

What are the different types of knee injections?

These are the main types of knee injections used in the treatment of osteoarthritis.

Corticosteroids

Corticosteroids are designed to be similar to cortisol, a hormone that is naturally produced in the body. The main purpose is to reduce inflammation.

Although oral corticosteroids are used to treat rheumatoid arthritis, which is a systemic disease, this isn’t an option for osteoarthritis.

If you have osteoarthritis in your knee, corticosteroids are most effective when injected directly into the joint. It’s a targeted treatment to reduce inflammation so bone doesn’t rub on bone as you move your knee.

The following medications are types of corticosteroids:

Hyaluronic acid (viscosupplements)

If you have osteoarthritis, you probably don’t have enough hyaluronic acid in your knees. This substance helps to coat your cartilage and acts as a lubricant and shock absorber so your knee can move freely.

Learn more: Viscosupplements: Comparing your options »

This thick medication serves to supplement your own hyaluronic acid and keep the bones from scraping against each other. It may also help decrease inflammation and ease pain.

The following medications are types of hyaluronic acid injections:

  • sodium hyaluronate (Euflexxa, Hyalgan, Supartz)
  • high-molecular-weight hyaluronan (Monovisc, Orthovisc)
  • hylan G-F 20 (Synvisc, Synvisc One)
  • cross-liked hyaluronate (Gel-One)

Fluid aspiration (arthrocentesis)

Rather than injecting something into the knee, this procedure takes fluid out of the knee. Removing excess fluid may provide immediate relief from pain and swelling. This is sometimes done prior to receiving an injection of corticosteroids or hyaluronic acid.

What does the procedure involve?

Knee injections can be administered in your doctor’s office. The procedure only takes a few minutes.

You’ll be seated during the procedure, and your doctor will position your knee. In some cases, they’ll use an ultrasound to help guide the needle to the best location.

First, the skin on your knee will be cleaned and treated with a local anesthetic. Your doctor will insert the needle into your joint. You might feel some pressure or mild discomfort. Then the medication will be injected into your joint.

In some cases, a small amount of joint fluid is removed first to make room for medication. For this, the doctor will use a needle attached to a syringe to enter the knee joint. The fluid is then aspirated into the syringe and the needle removed.

After the fluid is removed, the same puncture site can be used to inject the appropriate medication into the joint.

A small bandage will be placed over the injection site and you’ll be able to go home fairly quickly. Your doctor may advise you to avoid straining your knees for the next day or so. Your knee may feel tender for a few days. Ask if there are any driving restrictions.

Pros and cons of knee injections for osteoarthritis

Before weighing the pros and cons, you’ll want to ask your doctor which type of injection they’re planning to give you. Each type carries its own set of pros and cons.

Pros

  1. Corticosteroid injections may provide immediate relief from pain and inflammation. Relief may last up to 24 weeks.
  2. Hyaluronic acid injections may take longer to provide relief, but the benefits can last three to six months.
  3. Side effects from hyaluronic acid may be less severe than those from corticosteroid injections.

Corticosteroid injections

On the plus side, a direct injection may provide immediate relief from pain and inflammation. There’s evidence to support short-term improvement of up to two weeks, as well as a longer response lasting up to 24 weeks.

On the other hand, not everyone gets relief after a corticosteroid injection. And it’s usually a short-term solution. You may not be able to have corticosteroid injections at all if your knee is severely damaged.

Potential side effects include:

  • swelling immediately following an injection
  • nerve damage
  • thinning of nearby bone

There’s also a limit on how often you can receive a corticosteroid injection to the same joint — usually only once every three or four months. Having too many injections can cause a breakdown of cartilage, making matters worse. It can also contribute to the development of high blood pressure, osteoporosis, and skin atrophy.

Potential pros and cons of hyaluronic acid injections

The injection can provide relief from pain and swelling, but it’s not immediate. Studies show that it takes about five weeks before you feel the full effects of the treatment. Relief may last from three to six months. Some people are not helped by hyaluronic acid injections.

Potential side effects include:

  • mild injection site skin reaction
  • arthritis flare-up immediately following the injection

Hyaluronic acid injections are administered differently depending on the manufacture or preparation being used. Some require one injection and others require several injections given weekly.

Potential pros and cons of fluid aspiration

Removal of excess fluid can provide immediate relief from pain and discomfort. Side effects may include bruising, swelling, or infection at the aspiration site.

What’s the outlook?

Following injections of the knee, notify your doctor if you have any signs of infection.

The effectiveness of these treatment methods varies from person to person. A lot depends on how far your arthritis has progressed. Some people respond well, but others get no relief.

Your doctor can advise you about which injections might be beneficial to you. If injections don’t work, talk to your doctor about your other treatment options, which may include stronger pain medications or surgery.

Read more: Alternatives to knee replacement surgery »

Tips for taking care of your knees

No matter what treatment you get for osteoarthritis of the knees, you should also take other steps to care for your knees. Here are a few tips to get started:

  • Try to minimize activities that strain your knees. Use an elevator or escalator instead of stairs, for example.
  • Avoid high-impact activities such as running or tennis. You can replace them with swimming, cycling, or walking, which are great forms of exercise that are also easy on the knees.
  • Maintain a healthy weight or lose a few pounds if you need to. Extra weight strains your knees.
  • Use heat and ice to soothe your knees.
  • If your knees are interfering with mobility, try wearing a knee brace or using a cane.
  • Consider physical therapy or a personalized exercise program with someone who is knowledgeable about osteoarthritis.
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