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Knee Injections in Bristol (Steroid, Hyaluronic Acid, PRP, Arthrosamid)

Knee injections can play an important role in managing arthritis pain, settling inflammation, and helping you get back to the activities that matter to you. I offer a range of injection treatments tailored to your diagnosis, the stage of your knee problem, and your goals – whether that is returning to sport, managing day-to-day comfort, or delaying or avoiding surgery.

On this page I explain the options I offer, the evidence behind each one, and how I decide which approach is most likely to help you.

When are knee injections useful?

Injections work best as part of a wider treatment plan. The situations where I most commonly use them are:

  • Settling a flare-up – a painful, swollen knee that is stopping you from exercising, sleeping, or getting on with daily life. A steroid injection can bring this under control quickly and create a window for physiotherapy.
  • Supporting rehabilitation – reducing pain and inflammation so that you can engage properly with strengthening exercises and physiotherapy.
  • Buying time – when surgery may be appropriate but the timing is not right (work, family, other health issues), an injection can bridge the gap effectively.
  • Longer-term symptom management – for patients who want to delay or avoid surgery, newer injection options such as PRP and Arthrosamid can offer sustained relief.

Steroid (corticosteroid) injection

Steroid injections – typically methylprednisolone (Depo-Medrone) or triamcinolone – are the most established and widely used knee injection. They work by reducing inflammation within the joint and are recommended by NICE (NG226) for short-term relief of osteoarthritis symptoms.

Evidence and what to expect

Steroid injections are effective at providing rapid pain relief, typically working within a few days. They are particularly valuable for settling an acute flare-up and creating a window where you can engage properly with physiotherapy and rehabilitation. The duration of relief varies between patients but is generally in the order of weeks to months.

I use steroid injections strategically – they are at their most useful when a knee is actively inflamed and the patient needs to get moving again. When used at the right time, they can make a real difference to your recovery.

Practical points

  • Usually works within a few days, sometimes up to 1–2 weeks
  • A short-term flare of pain for 24–48 hours after injection is common and should settle
  • Patients with diabetes should be aware that blood sugars may rise temporarily for a few days
  • Works best when paired with physiotherapy and a rehabilitation plan

Hyaluronic acid (viscosupplementation)

Hyaluronic acid is a gel-like substance that occurs naturally in joint fluid. Injecting it into the knee helps restore some of the lubrication and shock-absorption that is lost in an arthritic joint. Products vary – some are given as a single injection, others as a course of three or five.

Evidence and what to expect

Hyaluronic acid can be helpful for selected patients with mild-to-moderate knee osteoarthritis, particularly those who want an alternative to steroid or who prefer to avoid repeated steroid use. Benefits are usually gradual, developing over several weeks. Some patients report meaningful improvement in comfort and function that lasts several months.

It is worth noting that hyaluronic acid is not routinely recommended or funded by the NHS under current NICE guidelines. I use it selectively in private practice where it fits a patient's particular situation – for example, when steroid alone has not been enough, or as part of a combined approach to managing symptoms alongside exercise and weight management.

PRP (platelet-rich plasma)

PRP is made from your own blood. A sample is taken, centrifuged to concentrate the platelets and their associated growth factors, and then injected into the knee. These growth factors help reduce inflammation and support the body's own healing response.

Evidence and what to expect

The evidence for PRP has grown substantially in recent years. Multiple meta-analyses – including a 2025 analysis published in the American Journal of Sports Medicine – report that PRP provides clinically meaningful improvements in pain and function at 3, 6, and 12 months. In several comparisons, PRP outperforms both hyaluronic acid and corticosteroid, particularly in mild-to-moderate osteoarthritis.

The quality of PRP matters. Leukocyte-poor PRP with a higher platelet concentration appears to produce the best results, and this is reflected in how I prepare and deliver the treatment. PRP is particularly well-suited to patients with earlier-stage arthritis who are keen to support their knee without surgery and are willing to allow 6–12 weeks for the full effect to develop.

Practical points

  • A blood sample is taken and processed on the day – the whole appointment takes around 30–45 minutes
  • A short-term pain flare for a few days after injection is common
  • You should avoid anti-inflammatory medication (ibuprofen, naproxen) for a period around the injection, as these may interfere with the biological response
  • Usually delivered as a course of 2–3 injections – allow 6–12 weeks to assess the full benefit

Arthrosamid (polyacrylamide hydrogel)

Arthrosamid is one of the most exciting developments in injection-based treatment for knee osteoarthritis. It is a 2.5% polyacrylamide hydrogel (iPAAG) – a biocompatible gel that is injected into the knee as a single treatment and integrates with the synovial lining of the joint. Unlike steroid or PRP, Arthrosamid is designed to provide long-lasting relief from a single injection.

Evidence and what to expect

The clinical data for Arthrosamid is encouraging and continues to grow:

  • The IDA study (Bliddal and colleagues) showed statistically significant reductions in pain (WOMAC scores) that were maintained at 1, 2, 3, and now 5 years of follow-up from a single injection. Ten-year safety data from this cohort was presented at the World Congress on Osteoporosis in 2025, confirming a reassuring long-term safety profile.
  • The LUNA study – the largest multicentre study to date with approximately 200 patients – reported meaningful reductions in pain at 12 months with no serious treatment-related adverse events.

The durability of Arthrosamid's effect is what sets it apart from other injection options. Because the hydrogel integrates with the joint lining rather than being absorbed, patients can benefit from a single treatment for a sustained period – something that is not possible with steroid or hyaluronic acid.

Who benefits most

I offer Arthrosamid to selected patients with moderate osteoarthritis who are looking for longer-lasting relief, particularly when shorter-acting injections have not provided sufficient duration of benefit, or when the patient wants to delay or avoid surgery. It is given as a single 6 ml injection under ultrasound guidance.

Practical points

  • Single injection given under ultrasound guidance
  • Prophylactic antibiotics are given before the injection
  • Improvement is gradual – typically assessed over weeks to months
  • Temporary swelling or discomfort after injection is common
  • Having Arthrosamid does not prevent or complicate a knee replacement if it becomes necessary in the future

How I decide which injection is right for you

The choice depends on what we are trying to achieve. A thorough assessment – your symptoms, examination findings, X-rays or MRI – comes first. Then we discuss which approach best matches your situation and goals.

  • Acute flare with swelling – steroid is usually the most effective first step to settle things down quickly
  • Mild-to-moderate arthritis, keen to avoid surgery – PRP has strong evidence in this group and can provide lasting benefit
  • Looking for longer-lasting relief from a single treatment – Arthrosamid is well-suited for selected patients who want sustained symptom improvement
  • Alternative to repeated steroid – hyaluronic acid or PRP can be a good option

If your knee is very swollen, I may aspirate (drain) the fluid before injecting. This reduces pressure, improves comfort, and allows the injection to work more effectively.

On the day

The skin is cleaned using a sterile technique. The injection is given into the knee joint – I use ultrasound guidance where appropriate, particularly for previously operated knees or where accuracy matters (such as with Arthrosamid). You can walk out of the clinic and go home the same day.

Aftercare

  • Keep things light for 24–48 hours – normal walking is fine
  • Avoid heavy exercise, running, or sport for a few days (this varies by injection type)
  • Ice and simple painkillers can help with any temporary soreness
  • Continue or restart physiotherapy as discussed – injections work best when they enable stronger rehabilitation

Risks

Complications from knee injections are uncommon, but you should be aware of them:

  • Infection – rare but serious. If you develop increasing redness, heat, fever, or worsening pain in the days after an injection, seek urgent medical assessment.
  • Post-injection flare – a temporary increase in pain and swelling for 24–72 hours. This is common and usually settles on its own.
  • Bruising – more likely if you take blood-thinning medication.
  • Vasovagal episode – feeling faint during or shortly after the injection.

Specific to injection type: steroid may temporarily raise blood sugars in diabetes. PRP commonly causes a short-term flare as part of the biological response. Arthrosamid is given with prophylactic antibiotics before the procedure as standard.

Frequently asked questions

Which injection is best for knee osteoarthritis?

It depends on the stage of your arthritis, what you need right now, and what you have already tried. Steroid is well-established for short-term relief of flare-ups. PRP has strong evidence for mild-to-moderate arthritis and can provide months of benefit. Arthrosamid offers the potential for the longest-lasting relief from a single injection. I help you choose the right option for your situation.

How quickly will I feel better?

Steroid usually works within days. PRP takes 6–12 weeks to reach full effect. Arthrosamid is gradual over weeks to months. Hyaluronic acid, when effective, is also gradual.

How long does the benefit last?

Steroid provides short-term relief, typically weeks to months. PRP, in patients who respond well, can last 6–12 months or longer. Arthrosamid's published data shows maintained benefit at up to 5 years from a single injection. All injections work best when combined with exercise and, where relevant, weight management.

Can injections help me avoid knee surgery?

For many patients, yes – particularly in earlier-stage arthritis. Injections can help you manage symptoms effectively and maintain an active lifestyle. If arthritis progresses to a point where surgery offers a better long-term outcome, we will discuss that openly, but many patients find that the right injection at the right time allows them to delay or avoid surgery altogether.

Can I have a knee injection in Bristol?

Yes. I offer the full range of injection treatments at my clinics in Bristol. The first step is a proper assessment so we can choose the approach that is most likely to help you.

Related

This information is intended to help you prepare for a consultation. It does not replace individualised medical advice. If you develop increasing redness, heat, fever, or worsening pain after any injection, seek urgent medical assessment.