Cortisone Shots in the Knee – Do They Really Work?

Are you considering getting cortisone shots in your knee? Although cortisone (corticosteroid) injections have been used for the past fifty years, some physicians are concerned that they may have adverse long-term side effects. Despite this, many patients experience significant pain relief from corticosteroid shots – depending on your circumstances this treatment may be right for you.

Cortisone shot into knee joint

What conditions do cortisone shots in the knee work for?

Corticosteroids are used to treat a variety of knee conditions such as tendonitis, bursitis, and osteoarthritis (figure 1).1  The first thing to note is that they are not considered a permanent solution. Corticosteroids can provide short term relief from knee pain but over time the beneficial effects will wear off. Because of this, the utility of corticosteroid injections is very situational. Professional athletes will often get injections to make it through key games during their season. Someone planning a long multi-week vacation may receive an injection to maximize mobility during their leisure time. Regardless of the cause of your knee pain, you should weigh the pros and cons of cortisone injections before deciding on treatment.

Knee conditions commonly treated with corticosteroids
Figure 1: knee conditions commonly treated with corticosteroids.

Learn more about other treatments for knee arthritis

How do cortisone injections work?

When you feel pain in your knee, it is usually the result of swelling (inflammation) in the joint. Inflammation occurs in response to injured or irritated tissues and structures. While it causes pain, it is also an important part of your body’s natural healing response.

Cortisone shots in the knee reduce inflammation by interrupting the cellular signaling pathway responsible for creating it. The damaged tissue that would normally trigger inflammation can no longer do so, allowing you to move with reduced levels of pain. After the shot, it takes some time for the corticosteroids to interact with the targeted area (hours to days). Once they take effect, symptoms should improve rapidly and remain better for several weeks. After this, the corticosteroids slowly degrade, and knee pain typically returns to its original intensity.

How much will cortisone injections help my knee pain?

knee pain reduction  – Cortisone versus placebo injection.
Figure 2: knee pain reduction – cortisone versus placebo injection.

Like any treatment, corticosteroid injections don’t work for all patients, and when they are effective results vary. Just 40% of patients report feeling better after receiving cortisone shots for knee arthritis. Those responding well to the treatment appear to receive a minimal benefit. The effectiveness of cortisone shots is often judged relative to placebo saline injections which contain no actual medicinal ingredients. One month after undergoing treatment, those who received cortisone injections report feeling slightly better than those who received the placebo – an average difference of 1 on a 10 point scale (figure 2).5 Better – yes, but only slightly so. You will have to weigh this benefit against the possible side-effects and long term consequences associated with the treatment.

How long do the benefits from cortisone shots last?

Improvements in knee pain in from cortisone shots typically peak around two weeks and can persist for up to 24 weeks.6 After 24 weeks knee pain tends to return to its original intensity.2 It’s also worth noting that after the first few weeks of treatment patients typically see very little benefits from cortisone shots compared with a placebo (figure 3).

 fluctuations in knee pain symptoms over time  – cortisone versus placebo injection
Figure 3: fluctuations in knee pain symptoms over time – cortisone versus placebo injection.

How much does it cost for a cortisone injection?

Spendonhealth reports that cortisone injections into the knee joint can cost anywhere between $100 – 300 USD. These costs likely vary a lot by region and country. Since cortisone shots are a well recognized medical treatment – much of the expense may be covered by your health insurance should you have it.

Are there any side effects from cortisone shots?

Cortisone shots are generally well tolerated with the most common side effect being soreness at the injection site. However, there are several other more serious side effects and complications that may occur after the shot.

Vasovagal Syncope: Syncope is medical jargon for fainting. After receiving the injection, approximately 10-20% of patients will temporarily experience lightheadedness, nausea, sweating and feeling faint.1

Post Injection Flare-Up: Nearly 10% of patients will experience an abnormal sharp increase in symptoms after their cortisone shot.1 Pain typically resolves in 3-5 days, at which point the treatment should progress normally.

Joint Infection: Infections from cortisone shots are rare (0.05%).1 However, due to the serious nature of infections, you should monitor your knee for excessive swelling and tenderness.

cartilage degeneration exposing bone after receiving multiple cortisone shots to the same area of the joint.
Figure 4: cartilage degeneration after receiving multiple cortisone shots to the same area of the joint.

Accelerated Cartilage Degeneration: Articular cartilage covers the surfaces of bones – helping them move against each other with minimal friction. Cortisone shots are well known to dramatically increase the breakdown of articular cartilage within joints (figure 4).2 A single injection can impair cartilage regeneration for up to 16 weeks.3

joint cartilage health in rats after being injected with cortisone.
Figure 5: joint cartilage health in rats after being injected with cortisone.

Paradoxically, some scientific research suggests that it may be wise to exercise less after a cortisone shot (figure 5).4 An animal study revealed that 100% of rats exhibited accelerated cartilage degeneration after receiving injections. In the rats that exercised in addition to the treatment – 70% showed signs of severe cartilage degeneration.4 This trend has been observed in human subjects as well (figure 6).2

The problem is essentially two-fold:

(1) Cortisone shots in the knee reduce your cartilage’s ability to regenerate itself at a cellular level.  

(2) Increased activity due to the absence of pain strains cartilage, accelerating degeneration.

joint cartilage in human hip joint after being injected with cortisone on several occasions.
Figure 6: joint cartilage in human hip joint after being injected with cortisone on several occasions.

What Other Alternatives are There?

Other Pharmacological Treatments: There are other types of injections for the knee joint such as hyaluronic acid (HLA) that could provide a similar benefit. Various prescription and over the counter oral anti-inflammatory medications are available as well.

Non-Drug Treatments: If you are worried about the risk of negative side effects associated with injections and oral pain killers – conservative treatment may be for you. The focus here is to avoid/delay surgery, get you off painkilling drugs and improve the health of your knee joint.

Unloader Knee Braces: If you have knee osteoarthritis and want to preserve what cartilage you have left, unloader knee braces could be the right fit for you. These knee braces actively reduce the pressure between the bones in your knee joint – significantly reducing pain.

Additional Resources

Corticosteroids – Arthritis Foundation   

Corticosteroids – Cleveland Clinic

Steroid Injections – National Health Service

References

  1. Stephens, M. B., Beutler, A. I., & O’CONNOR, F. G. (2008). Musculoskeletal injections: a review of the evidence. American family physician, 78(8).
  2. Hauser, R. A. (2009). The deterioration of articular cartilage in osteoarthritis by corticosteroid injections. Journal of Prolotherapy, 2, 107-23.
  3. Chunekamrai S. Changes in articular cartilage after intraarticular injections of methylprednisolone acetate in horses. Am J Vet Res. 1989;50:1733-1741.
  4. Gogia PP, et al. Hydrocortisone and exercise effects on articular cartilage in rats. Arch Phys Med Rehabil. 1993;74:463-467.
  5. Jüni, P., Hari, R., Rutjes, A. W., Fischer, R., Silletta, M. G., Reichenbach, S., & da Costa, B. R. (2015). Intra‐articular corticosteroid for knee osteoarthritis. Cochrane Database of Systematic Reviews, (10).
  6. Arroll, B., & Goodyear-Smith, F. (2004). Corticosteroid injections for osteoarthritis of the knee: meta-analysis. Bmj, 328(7444), 869.