A Guide to Knee Injections for Osteoarthritis

Date: May-27-2016 When knees are sore, stiff, and swollen from osteoarthritis, several treatment options are available.

Treatment for knee osteoarthritis (OA) may start with non-drug interventions like exercise or weight loss. Another option is over-the-counter pain relievers such as acetaminophen (Tylenol), aspirin, or ibuprofen (Motrin, Aleve).

If these treatments don't work, a doctor may recommend injections. The Food and Drug Administration (FDA) have approved two injections to treat knee OA: hyaluronic acid and corticosteroids.

Here's a look at how both types of injections work.

Contents of this article:

Hyaluronic acid injections

Corticosteroid injections

Talking to a doctor about injections

Hyaluronic acid injections (viscosupplementation)

Hyaluronic acid is a gel-like substance found naturally in the synovial fluid that surrounds your joints. This substance helps lubricate and cushion your joints. It acts as a shock absorber, helping the bones move smoothly instead of grinding against one another.

Hyaluronic acid injections are also known as viscosupplementation.

People with OA have lower than normal amounts of hyaluronic acid in their joint fluid. Hyaluronic acid injections can restore what may be missing. These injections not only lubricate the joint but may also reduce inflammation and protect the cartilage from further wear and tear.

A doctor or other healthcare provider will give between one and five shots in the knee. The number of shots needed depends on which brand of hyaluronic acid the doctor uses. The injections are given 1 week apart.

Before giving an injection, the doctor may remove some of the fluid from the knee joint with a needle to bring down swelling. This procedure is called aspiration.

For a few days after a shot, the patient should avoid putting a lot of weight on the affected knee. They should not jog or run, stand for long periods of time, or lift heavy objects.

Typical side effects from hyaluronic acid injections include:

Pain in the knee

Bruising

Warmth

Slight swelling

These side effects should go away after a few days. Applying an ice bag to the knee can help relieve discomfort and help prevent swelling after the shots.

In rare cases, people can have more serious side effects, such as bleeding, infection, or an allergic reaction to the injection. People should call a doctor right away if any of these symptoms occur:

A lot of swelling in the knee

Rash

Redness or warmth in the knee

Severe pain

It can take several weeks after the injections before OA pain starts to ease up. The pain relief typically lasts for about 6 months. Once the effect wears off, another round of shots or a different treatment is needed. Most insurance carriers will allow a second round 6 months after the last series of injections if the patient received a benefit from the prior injections.

Hyaluronic acid injections won't stop or reverse arthritis. However, they may slightly ease OA pain - at least temporarily - in some people who get them. These injections may also improve movement. People with mild OA are likely to see the greatest benefit.

Corticosteroid injections

Steroid medicines act like the hormone cortisol, which works on the immune system to reduce inflammation in the body. Reducing inflammation also relieves pain. Five different steroid medicines are FDA-approved to treat OA. All of them are about equally effective.

Doctors sometimes use ultrasound scanning to help with knee injections.

Patients will need to see a doctor for the injection. Doctors sometimes use ultrasound to see where to place the needle. Ultrasound is a type of scan that uses sound waves to create images of the inside of the body. Using ultrasound can help the doctor find the joint space.

The doctor may also give an injection of anesthetic pain reliever along with the steroid injection. The anesthetic will give immediate relief. The steroid should then start working within a few days.

Corticosteroids go to work faster than hyaluronic acid injections, but their effects don't last as long. In some people, corticosteroid injections can help relieve pain and improve movement in the joint. Others don't find any pain relief from these shots.

People with a lot of knee joint damage are less likely to see results. Even if the pain does improve, it may start to come back about several weeks to a few months after the shot.

Although corticosteroid shots are considered safe, it is possible to have side effects such as:

Irritation in the joint that is similar to gout (called "crystal flares")

Nerve damage

Infection (rarely)

Increase in blood sugar levels (this can be a problem for people with diabetes)

Thinning of bones near the knee

If the effects wear off, patients may not be able to get another shot right away. Corticosteroid injections are only recommended once every 3-4 months. Having too many shots can increase the risk of side effects like damage to soft tissues in the knee.

If injections every few months aren't enough to relieve the pain, another treatment may be needed. If the interval between injections is less than 3-4 months, the relief of pain from the injection also is not as great and wears off faster.

Talking to a doctor about injections

Two other types of injections are available. Though these treatments are still experimental and are not yet FDA-approved for knee arthritis, some doctors may be able to use them.

Platelet-rich plasma (PRP) injections

These injections use cells called platelets, which help wounds heal and blood clot. The doctor will take the platelets from the patient's own blood. Once inside the knee joint, platelets release substances called growth factors that help fix damaged tissues. PRP injections may relieve OA pain and improve function.

Stem cell injections

These injections use cells that can develop into any type of tissue in the body to repair damaged cartilage in the knee. Stem cell injection treatment can help bring down swelling and relieve pain.

People who think they might have OA of the knee should ask a doctor if knee injections are right for them. Before turning to injections, other treatments are available, like physical therapy, heat, ice, and weight loss.

Written by Stephanie Watson

Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.