How long does a knee steroid injection last?

mskultrasoundinjec
May 11
4 min read

Knee pain can affect everyday activities such as walking, climbing stairs, exercising, or even getting out of a chair comfortably. For many patients, a steroid injection can help reduce pain and improve movement, particularly when inflammation is contributing to the symptoms.

One of the most common questions patients ask is:

How long does a knee steroid injection last?

In most cases, patients can expect symptom relief for around three months, although the response varies from person to person. Some people experience shorter relief, while others continue to feel improvement for several months afterwards.

The duration often depends on the underlying cause of knee pain, the severity of the condition, and how much inflammation is present within the joint.

What is a knee steroid injection?

A knee steroid injection is a treatment used to reduce inflammation inside the knee joint.

The injection usually contains:

A corticosteroid medication to reduce inflammation
A local anaesthetic to provide short-term pain relief

Steroid injections are commonly used to help manage:

Knee osteoarthritis
Inflammatory flare-ups
Swelling within the knee joint
Pain associated with wear-and-tear changes

Many patients choose this treatment because it can:

Reduce pain
Improve mobility
Help them return to normal activities
Support physiotherapy and rehabilitation

How long does the relief usually last?

The average response is typically around three months, although every patient responds differently.

Some patients may experience:

Relief lasting only a few weeks
Improvement lasting several months
Significant pain reduction that improves walking and daily activities

In general, patients with mild or moderate inflammation often respond better than those with very advanced arthritis.

When does a knee steroid injection start working?

The effect is not always immediate.

Most patients notice improvement:

Within a few days
Or gradually over one to two weeks

It is also common to experience a temporary increase in discomfort during the first 24–48 hours after the injection before symptoms begin to settle. This temporary flare-up is usually short-lived.

What affects how long a knee injection lasts?

Several factors influence how long the benefit may last.

The underlying cause of knee pain

Steroid injections work particularly well when inflammation is a major contributor to symptoms.

Common examples include:

Osteoarthritis with inflammation
Synovitis (inflammation of the joint lining)
Swollen knees with excess fluid inside the joint

If you would like to understand more about arthritis-related knee pain, you can also read more about Knee Osteoarthritis.

The severity of arthritis

Patients with:

Mild to moderate arthritis often achieve very good symptom relief
More advanced arthritis may still benefit, although the effect may not last as long

Even temporary pain reduction can still be valuable by improving mobility and quality of life.

Activity levels after the injection

What happens after the procedure can influence the outcome significantly.

Patients are usually advised to:

Rest the knee for approximately 48 hours
Avoid strenuous activity initially
Gradually return to exercise and normal activities

Overloading the knee too early can sometimes shorten the duration of relief.

Injection accuracy

Accuracy is important when performing a knee injection.

Using ultrasound guidance allows the medication to be delivered precisely into the joint space. This may:

Improve accuracy
Maximise effectiveness
Improve patient comfort during the procedure

Ultrasound guidance can be particularly helpful in patients with:

Significant arthritis
Smaller joint spaces
Swelling within the knee to allow for aspiration of excess fluid at the time of injection

Can a knee steroid injection cure arthritis?

No — a steroid injection does not reverse arthritis or permanently repair wear-and-tear changes within the joint.

Instead, it works by:

Reducing inflammation
Calming pain within the knee
Improving movement and function

For many patients, this creates a valuable period of reduced pain that allows them to:

Stay active
Continue physiotherapy
Improve strength and mobility
Delay more invasive treatments

Who is a good candidate for a knee steroid injection?

Knee steroid injections may help patients who have:

Knee osteoarthritis
Persistent inflammation
Swelling inside the knee
Pain limiting normal activities
Symptoms not improving with rest or physiotherapy

They are often considered when:

Painkillers alone are not helping sufficiently
Symptoms interfere with walking or sleep
Patients want to avoid or delay surgery

How often can you have a knee steroid injection?

If the injection works well, it can usually be repeated when appropriate.

In most cases:

Injections are spaced at least three months apart
Repeated injections are used selectively and carefully

The exact approach depends on:

The severity of arthritis
Previous response to treatment
Overall joint condition

A good response to the first injection is often a positive sign that inflammation is contributing significantly to symptoms.

What if the knee cortisone injection does not last long?

A shorter duration of relief does not necessarily mean the treatment has failed.

Sometimes it may indicate:

More advanced arthritis
Mechanical joint problems
The need for additional treatment approaches

Other options may include:

Physiotherapy
Activity modification
Weight management
Hyaluronic acid injections such as Durolane
Further imaging or specialist assessment

Are ultrasound-guided knee injections better?

Ultrasound guidance helps improve the precision of the injection by allowing direct visualisation of the joint.

Potential advantages include:

More accurate placement
Better targeting of inflammation or fluid
Increased confidence during the procedure
Improved comfort for some patients

This is one reason why many patients prefer ultrasound-guided injections rather than landmark-guided injections.

What are the possible side effects?

Most patients tolerate knee steroid injections very well.

Possible temporary side effects can include:

Mild discomfort after the injection
A temporary pain flare
Facial flushing
Raised blood sugar levels in diabetic patients

Serious complications are uncommon.

Patients are usually advised to seek medical attention if they develop any signs of infection:

Increasing redness
Significant swelling
Fever
Severe worsening pain

Final thoughts

For many patients, a knee steroid injection can provide meaningful pain relief and improved mobility.

Most people can expect the benefits to last for around three months, although the response may be shorter or longer depending on the underlying condition and severity of inflammation within the joint.

When used appropriately, knee steroid injections can be an effective way to reduce pain, improve quality of life, and support rehabilitation.