Understanding Types of Knee Injections for Osteoarthritis

There are several types of knee injections commonly used to ease osteoarthritis discomfort. Corticosteroid injections work by quickly reducing inflammation and swelling, often providing relief for a few weeks. Hyaluronic acid injections, sometimes called gel injections, top up the knee’s natural joint fluid to improve cushioning and lubrication, which can be especially helpful in mild to moderate cases. More recently, hydrogel injections such as Arthrosamid have started to appear in private clinics. These involve filling the joint with a gel-like material to support damaged cartilage, potentially offering longer-lasting relief.

Platelet-rich plasma (PRP) injections are another emerging treatment that’s gaining attention. According to recent European expert guidelines, PRP is “considered appropriate in patients aged 80 or younger with mild to moderate knee osteoarthritis (KL grade 0-III), after other conservative or injection treatments have been tried” (Kon et al., 2024). However, it's not recommended as a first treatment or for more advanced osteoarthritis cases.

We’re also seeing growing interest in stem cell injections. Research highlights that “various cell products can be injected into the knee,” such as bone marrow concentrates and fat tissue extracts (Andia & Maffulli, 2021). Yet, it’s important to note that “current research is still trying to confirm if these injections offer real clinical benefits.” Public interest in stem cells has increased significantly over the last decade too, with online searches rising sharply since 2010 (Strotman et al., 2019).

Which injection is best really depends on your age, symptom severity, and overall health. Corticosteroids suit those needing quick relief from flare-ups, while hyaluronic acid, PRP or hydrogel injections may be better for more sustained symptom control. The NHS is still reviewing many of these options, and some are mainly available through private clinics.

Comparing Access and Costs: NHS vs Private Knee Injections

How easily you can get knee injections varies. Corticosteroids tend to be widely available on the NHS, but you might face waiting lists depending on your locality. Hyaluronic acid injections are less commonly offered on the NHS and usually have stricter eligibility due to their cost. Treatments like hydrogel or PRP injections are often only available privately.

Stem cell and biological injections remain experimental and are rarely found in routine NHS care. Experts warn that “clinical studies so far don’t give us clear answers about their effectiveness or the best way to use them” (Andia & Maffulli, 2021). Moreover, there’s a recognised need for “well-designed studies to keep up with the growing public interest in stem cell therapies” (Strotman et al., 2019).

If choosing private treatment, providers such as Bupa or Nuffield Health offer a range of injections with shorter waiting times but higher fees. Corticosteroid shots may cost around £150 to £250, hyaluronic acid £300 to £500, and PRP sessions typically range from £500 to £800. Hydrogel injections can exceed £1000, depending on the clinic. Searching for “private cortisone injections near me” or “hyaluronic acid injection near me” online can help you find private clinics that provide personalised care quickly.

Weighing Benefits and Side Effects: What Should Patients Expect?

Each injection type comes with benefits and potential side effects. Corticosteroids usually ease pain within a few days and last up to six weeks, but repeated use might damage cartilage. Side effects can include short-term flare-ups, minor infection risk, and skin changes at the injection site. Hyaluronic acid injections may take a few weeks before you notice improvements, which can last several months. Some patients experience mild swelling or discomfort after treatment, which generally settles.

PRP injections are recommended mainly after other treatments have failed, and typically for less severe osteoarthritis. The European consensus states PRP is “not appropriate as a first treatment or for end-stage (KL IV) osteoarthritis” (Kon et al., 2024). Side effects tend to be mild, such as short-term pain or swelling.

Hydrogel injections, like Arthrosamid, are promising for longer-term cushioning, with many patients reporting relief lasting a year or more. Side effects are rare but can include joint swelling or sensitivity.

When it comes to stem cell injections, there’s still much uncertainty. Experts point out that “important clinical questions remain unanswered, such as the right dosage and timing of injections” (Andia & Maffulli, 2021). If you are considering these experimental treatments, thorough discussion with a specialist is essential.

Aftercare and Recovery: What Happens After a Knee Injection?

After your injection, recovery advice varies depending on the treatment. Corticosteroid injections usually require rest for 24 to 48 hours and avoiding heavy exercise to help the medication take effect and reduce irritation risks. Hyaluronic acid and PRP injections often allow a return to light activities sooner but recommend steering clear of strenuous exercise for a few days. Hydrogel injections may require gentle activity initially to allow the gel to settle.

For newer cell-based treatments, aftercare guidelines are less well established, since protocols differ depending on the exact therapy and patient factors. Experts highlight that “variation in patients and study designs makes it difficult to standardise post-injection care” (Andia & Maffulli, 2021).

Simple aftercare tips include using ice packs to reduce swelling, elevating the leg if swollen, and watching for unusual pain or signs of infection. Contact your doctor if you experience redness, severe swelling, or fever. Follow-up appointments are important to track your recovery and discuss the next steps, including physiotherapy if recommended. Many patients benefit from combining injections with lifestyle changes like weight control and strengthening exercises.

Conclusion

Knee injections offer a valuable way to ease osteoarthritis pain and improve mobility, balancing benefits, costs, and recovery time. Corticosteroid injections provide fast relief, while hyaluronic acid, PRP, and hydrogel injections may bring longer-lasting benefits depending on your needs. Advanced options like stem cell therapies remain experimental and should be approached with caution and medical advice. NHS access may involve waiting and eligibility rules, but private care can speed up treatment at a higher price.

As science advances, these treatments continue to improve, helping many stay active and comfortable with knee osteoarthritis. By understanding your options and following expert advice, you can make informed choices for your knee health.

References

• Andia, I., & Maffulli, N. (2021). Mesenchymal stromal cell products for intra-articular knee injections for conservative management of osteoarthritis. Journal of Orthopaedic Surgery and Research, 16(1). https://doi.org/10.1177/1759720X21996953
• Strotman, P. K., Novicoff, W., Nelson, S. J., & Browne, J. (2019). Increasing public interest in stem cell injections for osteoarthritis of the hip and knee: A Google Trends analysis. The Journal of Arthroplasty, 34(7), 1310–1315. https://doi.org/10.1016/J.ARTH.2019.03.002
• Kon, E., de Girolamo, L., Laver, L., Andriolo, L., Andia, I., Bastos, R., ... Filardo, G. (2024). Platelet-rich plasma injections for the management of knee osteoarthritis: The ESSKA-ICRS consensus. KSSTA. https://doi.org/10.1002/ksa.12320