Overall, exercise therapy is the best form of medicine for knee arthritis. Also, other factors such as weight loss and reducing cholesterol and sugar are essential. However, some people find that treating these lifestyle factors is not enough. Yet, they don’t want to resort to costly and invasive joint replacement surgery. Instead, some turn to injections such as cortisone or hyaluronic acid. So, cortisone vs. hyaluronic acid for knee pain: which is better, and what should we use?

Cortisone injections

cortisone injections

Cortisone is an anti-inflammatory that reduces pain, swelling, and inflammation.

Your body makes corticosteroids naturally by the adrenal glands on top of your kidneys. Its effects on the body include reducing inflammation and maintaining blood pressure and sugar levels. Cortisone is a synthetic or manufactured corticosteroid that mimics these effects. 

Cortisone injections are the most commonly used in osteoarthritis and are usually administered with the help of imaging, such as ultrasound.

How effective are cortisone injections?

Good evidence suggests that cortisone improves pain and function within 1-2 weeks. This effect lasts for up to 3 months. However, they stop working after three months and sometimes don’t work.

On the negative side, a few studies have found that repeated cortisone injections lead to more rapid cartilage loss. In addition, there is some added evidence that repeated injections lead to earlier joint replacements. Overall, there are some questions about the use of cortisone injections in arthritis. We should limit cortisone in arthritis to those cases with severe pain and swelling.

Generally, it would be best if you had a cortisone shot in the knee by ultrasound guidance. These are the four questions you should ask before having an injection under ultrasound. 

Also, after a cortisone injection, you should take simple steps to ensure you get the best out of your cortisone injection. This blog outlines ideal post-injection care after a cortisone injection to get the maximal effect.

Hyaluronic acid injections 

natural gel injection

Hyaluronic acid is a naturally occurring substance found in joints and bones. It forms part of the synovial fluid in joints and acts as a lubricant and shock absorber. However, in a diseased joint, the amount of hyaluronic acid reduces.

Hyaluronic or gel injections involve injecting joints with hyaluronic acid to decrease pain and improve function. It is vital to ensure that hyaluronic acid, like cortisone, is injected into the joint. So, ultrasound guidance is recommended.

How effective are hyaluronic acid injections?

Unlike cortisone, the effect of hyaluronic acid is not immediate. It often takes up to 4 weeks to notice an impact. However, the result usually lasts longer than cortisone, averaging 6 to 12 months. For example, in a recent study on a high molecular weight hyaluronic acid (Durolane), the average effect lasts about 15 months.

Research suggests that the results of hyaluronic acid for knee arthritis are mixed. Many studies have reported reduced pain, but others have shown no effect. However, the results seem better with the high molecular weight hyaluronic acid like Durolane. Also, there are few adverse outcomes and no potential negative impact on cartilage like cortisone. In addition, some evidence suggests that hyaluronic acid can delay the time to knee replacement surgery.

You must manage your activity after a hyaluronic acid injection. This blog outlines the management of activity after a knee gel injection. 

So cortisone vs. hyaluronic acid for knee pain: which is better?  

In deciding which one to use, you need to consider several factors.

Hyaluronic or gel injections work best for people with little or no swelling but a grumpy joint—for example, a 45-year-old recreational footballer with mild knee arthritis. People need no significant downtime after gel injections. Moreover, the effect of a hyaluronic acid injeciton usually lasts for 6-18 months. Also,  these gel injections are suitable for people who are allergic to steroids or can’t use steroids for medical reasons.

On the other hand, cortisone injections work best for those people who need a quick pain relief fix. Usually, people with a swollen and painful joint are most suitable for a cortisone injection. A perfect example would be a swollen knee joint from acute gout. However, cortisone is not ideal for a longer-lasting effect on a chronic grumpy joint. Also, there is evidence that repeated cortisone injections lead to more significant wear and tear in the cartilage and a faster rate to knee replacement.

Finally, some people choose to have both injections. For example, people with a swollen joint choose to have cortisone first, followed by a hyaluronic injection four weeks later. In some cases, people choose to have both injections together simultaneously. However, mixing cortisone with hyaluronic acid leads to a faster breakdown of hyaluronic acid. Your doctor can speak to you about the best option for your particular case.

Which drug – cortisone or hyaluronic acid – is better for the health of the cartilage? 

Recent evidence suggests that cortisone injections have more significant arthritis progression than hyaluronic acid. One study found that people who had a cortisone injection showed more significant cartilage damage on an MRI than those who had hyaluronic acid. Another study found that arthritis progressed more rapidly in those with a history of cortisone injections than in those with hyaluronic acid.

Do you have alternatives to cortisone shots in the knees? 

Platelet-rich plasma injections

vials of human blood being removed from a centrifuge for knee shot for arthritis

Platelet-rich plasma, also known as PRP, is obtained from your blood. This blood is spun in a centrifuge to concentrate the platelets and separate them from the other cells. We then inject this plasma into a joint. Platelets release growth factors, which induce healing and pain reduction.

Recent evidence comparing PRP, hyaluronic acid, and cortisone suggests that PRP might have a better effect at 6 and 12 months – although the differences with hyaluronic acid are minor. Also, we don’t know what the optimal dose of platelets is. Some studies suggest a higher concentration of platelets is better, while others suggest lower concentrations are better. 

Arthrosamid injections

Another option is Arthrosamid, a hydrogel material with water molecules attached to a polyacrylamide backbone. It is non-degradable, meaning the body can’t break it down. When injected into the knee joint, the hydrogel is taken up by the synovial cells and incorporated into a new synovial lining. We think the hydrogel reduces inflammation in the synovial lining, thereby reducing pain and swelling in the joint. It also provides cushioning of the inner joint capsular tissue.

New studies show that Arthrosamid positively affects pain and function in knee arthritis from six weeks. This positive effect continues to increase until about six months. Also, recent data suggests that this positive effect can last up to three years, considerably better than PRP or hyaluronic acid. 

Compared to PRP and hyaluronic acid (where 70% have a positive effect), Arthrosamid shows better effectiveness, with 80% of patients rating this injection as effective. 

Arthrosmaid is currently approved for use in Europe and the UK. It is awaiting approval in Canada, Australia and US. 

Frequently asked questions about hyaluronic acid or cortisone:

What is the best gel injection for the knee?  

A higher molecular hyaluronic acid, such as Durolane, is better. Generally, they are more cross-linked, making them bigger so they last longer. Also, recent evidence suggests that 70% of people are satisfied after a Durolane injection for arthritis.

Do gel injections in the knee hurt? 

Generally not. However, these injections should be done under ultrasound to ensure the gel gets into the joint. If the gel is injected into the fat near the joint, there is a chance of developing a severe reaction called ‘pseudosepsis.’ You should ask these four questions before having an ultrasound-guided injection.

Can you combine both cortisone and hyaluronic acid for knee pain? 

Yes. Some people choose to have a cortisone injection first to produce an immediate effect. Then, about four weeks later, we use a gel shot to give a longer-lasting result. Others choose to have cortisone and hyaluronic acid together. A recent review suggested combining cortisone with a gel for knee pain is better than gel alone. However, other studies show that injecting cortisone with hyaluronic acid reduces the effect of hyaluronic acid.

Also, some doctors combine PRP and hyaluronic acid for a better effect. For example, one study found that combining PRP with hyaluronic acid reduced pain at 3, 6, and 12 months and had fewer side effects than PRP alone.

Can you only have three cortisone injections in a lifetime?

Generally, if the first injection doesn’t work, the second and third probably won’t either. Moreover, you should limit yourself to 2-3 injections in one area over 3-6 months. However, the rule that you can only have three in a lifetime is wrong. You can have injections into different parts of the body.

Cortisone injections will weaken my bones and make me fat. Is this true? 

As discussed above, the amount of cortisone moving throughout your body after an injection is tiny. The cortisone is usually cleared from your body after a week or two. So, we don’t think you should be too concerned about weak bones or weight gain unless you have multiple injections.

How long do you wait for knee surgery after a cortisone shot?

We think that you should wait six months for knee surgery after a cortisone shot. Recent studies suggest that the risk of infection is increased to 3 months and possibly up to six months. Also, the risk is not just for knee replacement. To be safe, we think you should wait six months to have knee surgery after a cortisone shot. 

Final word from Sportdoctorlondon about cortisone vs hyaluronic acid for knee pain

Given recent evidence suggesting cortisone harms joints, we recommend avoiding cortisone injections unless you have a swollen joint. Both hyaluronic acid and PRP are good options for knee arthritis. Sometimes, combination therapy using cortisone and hyaluronic acid is justified – although rarely.

More topics on injections related to cortisone vs. hyaluronic acid for knee pain:

Dr Masci is a specialist sports doctor in London. 

He specialises in muscle, tendon and joint injuries.