By Mr Philip Dobson, Consultant Orthopaedic Surgeon specialising in knee and hip conditions in Newcastle (Newcastle Hospitals NHS and Nuffield Health).

Knee arthritis is a common cause of pain and reduced mobility. When symptoms persist despite physiotherapy and simple measures, injection treatments can be an effective way to improve pain and function.

A range of injection treatments are available for knee arthritis. Two of the most commonly used options are corticosteroid (steroid) injections and platelet-rich plasma (PRP) injections. In some patients, these treatments may help delay the need for knee replacement surgery.

Patients often ask:

“Which injection is better?”

The answer depends on your symptoms, the severity of arthritis, and your treatment goals. These injections work in very different ways and are used in different clinical situations.

How do steroid injections work?

Corticosteroid injections reduce inflammation within the joint.

They are particularly helpful when arthritis is causing an inflammatory flare, with increased pain and swelling.

Most patients experience relatively rapid pain relief following a steroid injection.

However, the effect is usually temporary, typically lasting from a few weeks to a few months. Steroid injections do not alter the underlying joint environment, and repeated frequent use is not recommended.

How does PRP work?

Platelet-rich plasma (PRP) injections are increasingly used as part of modern joint preservation strategies. PRP is prepared from a small sample of your own blood.

The platelets contain natural growth factors that help regulate inflammation and support the tissues within the joint.

Unlike steroid injections, which primarily suppress inflammation, PRP works by influencing the biological processes within the joint. The aim is to improve symptoms by supporting the joint environment rather than providing short-term relief alone.

PRP has been studied extensively in knee arthritis and is increasingly used as part of modern joint preservation strategies.

What are the main differences?

Although both treatments are used for knee arthritis, they have different roles.

Steroid injections:

• Act quickly to reduce inflammation
• Often provide short-term pain relief
• Useful for flare-ups of symptoms

PRP injections:

• Work more gradually
• Aim to support the joint environment
• May provide longer-lasting symptom improvement in some patients
• Supported by a growing body of clinical research

These differences mean that the choice of injection depends on the clinical situation and patient goals.

Which patients are best suited to steroid injections?

Steroid injections are often most helpful for:

• Sudden worsening of knee pain
• Significant inflammation or swelling
• Patients needing short-term symptom relief
• Situations where rapid improvement is important

They can be an effective way to settle symptoms and improve comfort in the short term.

Which patients may benefit from PRP?

PRP is commonly considered for patients who:

• Have mild to moderate knee arthritis
• Experience ongoing symptoms despite physiotherapy
• Wish to remain active
• Are looking for a treatment that supports longer-term symptom improvement
• Want to explore options that may help delay surgery

In these patients, treatments that support the joint environment are often considered as part of a broader management plan.

How quickly do they work?

Steroid injections often provide relief within a few days.

PRP tends to work more gradually, with improvement developing over several weeks.

This difference is important to understand when deciding which treatment is most appropriate.

How long do the effects last?

Steroid injections typically provide relief for weeks to a few months.

PRP may provide longer-lasting symptom improvement in some patients, although results vary.

Neither treatment is permanent, and responses differ between individuals.

Are these injections safe?

Both steroid and PRP injections are widely used and generally safe when performed in an appropriate clinical setting.

Steroid injections have a long track record, although repeated use should be limited.

PRP uses your own blood, and the risk of allergic reaction is extremely low. As with any injection, there is a small risk of infection, but this is uncommon.

Which injection is right for you?

The most appropriate treatment depends on:

• The severity of your arthritis
• Your symptoms
• Your activity level
• Your treatment goals

In some cases, a steroid injection may be the best option for short-term relief. In others, treatments that aim to support the joint environment may be more appropriate.

A personalised approach is essential.

Specialist assessment

If you are experiencing ongoing knee pain, a specialist assessment can help determine the cause of your symptoms and the most appropriate treatment options.

In my practice, both corticosteroid and platelet-rich plasma (PRP) injections are used as part of a comprehensive approach to managing knee arthritis.

In more advanced arthritis, knee replacement surgery remains the most reliable treatment.

The aim is always to reduce pain, improve function, and help you return to the activities that matter to you.