Knee replacements are a standard orthopaedic procedure to treat knee arthritis. While 80% of patients with a knee replacement report good results, about 15-20% struggle with ongoing pain after a knee replacement. We use cortisone injections to treat pain and inflammation from knee arthritis. So, can you get a cortisone injection after a knee replacement to treat post-surgical knee pain, and what are the risks? 

What is cortisone?

cortisone drug

Cortisone is a powerful anti-inflammatory medication. When injected directly into the joint, cortisone can reduce inflammation and alleviate pain. This makes it a valuable tool for managing joint-related conditions, including arthritis, bursitis, and tendonitis.

Cortisone injections after knee replacement: increased risk of infection

Not only does cortisone reduce inflammation, but it also has a powerful effect on suppressing the immune system. We think this effect on the immune system increases the risk of infection. Cortisone also impairs tissue healing, making the knee replacement more vulnerable 

Performing a cortisone injection in a knee replacement can introduce bacteria into the joint. The risk of infection increases when combined with the adverse effects of cortisone, such as immune suppression and impaired healing. An infected knee replacement can be severe, often requiring long-term antibiotics and additional surgeries. 

A recent study looking at all the evidence for infection after a cortisone injection after a knee replacement found the following:

  • A cortisone injection after a knee replacement was a high-risk procedure 
  • The risk of infection increased by over 50% after a cortisone injection 
  • We don’t know how effective a cortisone injeciton is after a knee replacement 

So, overall, we strongly advise against a cortisone injection after a knee replacement.

Can you carry out a cortisone injection around a joint replacement?

Yes. Sometimes, pain after a knee replacement can be due to the prosthesis pinching soft tissue outside the joint. Examples include fat pad impingement, iliotibial band inflammation or nerve trapping. Sometimes, we use a targeted cortisone infection to reduce soft tissue inflammation. The cortisone injection must be done with ultrasound guidance to improve accuracy and prevent accidental injection into the joint. 

If you have pain after a knee replacement, you must see your surgeon to exclude other causes of pain, such as prosthesis loosening or malpositioning, infection fractures, or metal allergy. 

What are other options for pain after a knee replacement? 

Generally, physical therapy to improve knee strength and mobility will settle most cases of soft tissue pinching. Other options include medications for chronic pain, such as amitriptyline or duloxetine

Other commonly asked questions about steroid injections after a knee replacement

Does a cortisone shot before a knee replacement increase the risk of infection? 

Yes. A recent systematic review of total knee replacements examined over 300,000 knee replacement patients. In this group, nearly half had a cortisone injection before their knee replacement. The alarming results suggest that a cortisone injection before a total knee replacement increases the risk of infection after surgery. This risk is high if the injeciton is performed within six weeks of surgery. And the risk of infection remains higher when cortisone injections are done within three months of surgery.

Can you perform a cortisone injection around a hip replacement? 

Yes. But like a knee replacement, we should avoid injecting into a hip replacement. However, in some cases, persistent hip pain can be due to the pinching of the hip flexor tendon against the hip prosthesis cup. So, a targeted cortisone injection surrounding the hip flexor tendon may reduce hip pain. 

Final word from Sportdoctorlondon about steroid injection after knee replacement

A cortisone injection after a knee replacement is a high-risk procedure and should be avoided. If you have pain after a knee replacement, you should see your surgeon to exclude a severe cause for pain, such as infection, prosthetic loosening, or replacement malpositioning. 

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