If you suffer from knee osteoarthritis, doctors can offer various treatments to relieve your symptoms. One option is to inject medication into your knee.
There are different types of injections, and they are an important part of knee osteoarthritis treatment for many people, according to Roy Altman, MD, an osteoarthritis expert at UCLA. Injections can be particularly helpful for people who have not found relief from NSAIDs like ibuprofen or who cannot take these medications due to side effects.
Osteoarthritis (OA) is a common form of arthritis that often affects the knees. It occurs when the cartilage – the smooth covering that protects the bones in the joint – breaks down. The surface of the bones becomes damaged, leading to pain, swelling, stiffness, and limitations in movement.
How Knee Injections Work
First, your doctor will give you a numbing injection to numb your knee.
Next, your doctor may use a needle to remove excess fluid from your knee.
After that, you will receive the pain-relieving injection, usually just below your kneecap. The shot should not hurt, and the medicine will work throughout the joint, says John Richmond, MD, orthopedic surgeon at New England Baptist Hospital in Boston.
Various treatments have side effects that you should discuss with your doctor beforehand. The two most common types of knee injections for osteoarthritis are corticosteroids and hyaluronic acid.
Reduce Inflammation with Steroids
Corticosteroid injections are useful for treating OA pain and swelling flare-ups with fluid accumulation in the knee, says Richmond.
These injections help relieve symptoms by reducing inflammation in the joint. But they are not a perfect solution in every case. When considering this treatment, keep the following in mind:
They work quickly. These injections provide „very fast“ relief, usually within 24 to 48 hours, says Richmond.
The benefit is short-term. On average, pain relief lasts 6 to 12 weeks, says Richmond. Often, this is enough to get through an osteoarthritis flare-up until the symptoms subside.
You should not use them frequently. A corticosteroid injection often works best the first time, says Altman. Afterward, they tend to provide less relief.
In most cases, Richmond advises his patients that they can use these injections two to three times a year. Excessive use can damage the cells in the knee that produce cartilage.
Hyaluronic Acid
Most of the fluid in a healthy knee consists of hyaluronic acid, says Altman. But if you suffer from knee osteoarthritis, the hyaluronic acid in your knee becomes thinner. Your doctor can inject more hyaluronic acid into your knee to boost supply.
Studies have shown that hyaluronic acid injections can help some people with osteoarthritis more than pain-relieving medications. Other studies have shown that they can improve symptoms as well as corticosteroid injections. When considering hyaluronic acid injections, keep the following in mind:
It is often not the first approach. Your doctor may recommend hyaluronic acid if:
- Your symptoms are not improved by pain-relieving medications or non-drug treatments like heat or ice.
- You cannot take pain medications like Advil or Motrin (ibuprofen), Aleve (naproxen sodium), or Tylenol (acetaminophen).
- A steroid injection is not sufficient, or you or your doctor are concerned about the side effects.
It can work in different ways. After an injection, hyaluronic acid helps cushion and lubricate the moving parts in your knee, says Altman. This effect is relatively short-lived. But the treatment also seems to provide a longer-term benefit by relieving pain and inflammation.
You may need more than one injection. In the US, there are five versions of hyaluronic acid injections available. Some types require only one injection. Others require up to five injections, usually within a period of five weeks. If needed, you can get another shot after 6 months, says Altman.
Platelet-Rich Plasma: Can it Help with Osteoarthritis?
Another treatment that has gained attention is platelet-rich plasma (PRP). This involves taking a blood sample and processing it to produce a fluid that contains an above-average amount of platelets, tiny cells that help with blood clotting. The doctor then injects the fluid back into your affected area.
The platelets in your blood contain natural chemicals that aid in healing injuries. Doctors have been treating other issues – such as tendon damage – with PRP for more than a decade.
However, experts know little about whether it works for knee osteoarthritis.