Arthrosamid® Injections for Knee Osteoarthritis: What You Need to Know

Knee osteoarthritis is a common and often debilitating condition. If you've explored options like physiotherapy, steroid injections, or oral medications without lasting relief, Arthrosamid® injections may offer a longer-acting alternative. This guide explains how Arthrosamid works, who it's suitable for, and—most importantly—what the success rate looks like.

What is Arthrosamid® and how does it work?

Arthrosamid® is an injectable polyacrylamide hydrogel (PAAG) that is used to treat knee osteoarthritis. It acts as a non-biodegradable viscosupplement, meaning it stays in the knee joint long term.

Mechanism of action:

• Cushions the joint by integrating into the synovial lining and absorbing shock.

• Reduces synovial inflammation, lowering joint pain and stiffness.

• Forms a stable, long-lasting hydrogel layer that remains in the joint for years.

Why ultrasound guidance matters:

• Precise placement into the intra-articular space.

• Minimised risk of misplacement or damage to surrounding tissues.

• Improved outcomes due to accurate delivery.

Ultrasound-guided Arthrosamid® injections are our standard approach to ensure maximum safety and benefit.

Who is a good candidate?

Suitable patients:

• Adults with moderate to severe knee osteoarthritis (Kellgren-Lawrence grades II–III).

• Individuals unresponsive to conservative care (physiotherapy, oral NSAIDs).

• Those seeking a non-surgical alternative to knee replacement.

When it may not be suitable:

• Active joint infection or broken skin over the injection site.

• Recent corticosteroid injection in the same joint (within 3 months).

• Severe deformity or instability of the knee.

• Allergy to polyacrylamide or previous joint replacement in the affected knee.

Patients undergo a full clinical assessment before the injection to confirm suitability.

So… what’s the success rate?

What does “success” mean?

Success is measured using:

• ≥30% reduction in pain (based on visual analogue scale or VAS).

• Functional improvements (WOMAC or KOOS scores).

• Patient-reported satisfaction (global improvement ratings).

Evidence from clinical trials:

Outcome Metric	3 Months	6 Months	12 Months	2+ Years
≥30% Pain Reduction	73–75%	78–80%	75–85%	70–75%
Functional Improvement	65–70%	70–72%	70–75%	65–70%
Overall Satisfaction	80–85%	80–85%	85–90%	80%+

Patient satisfaction remains high up to two years post-injection, based on European observational studies and post-market data (Ref: Horvath et al., 2022).

What does this mean for you?

Most patients experience meaningful pain relief and better mobility within 4–12 weeks. However, responses vary—some feel better within days, others take longer or may not benefit.

How long do results last?

Duration of benefit:

• Sustained relief was reported for up to 2 years in many cases.

• No degradation of the hydrogel, as it's non-biodegradable.

• Some patients may require repeat injections after 24–36 months.

Short-term vs long-term outcomes:

• Short-term (up to 6 months): noticeable reduction in pain and stiffness.

• Long-term (12–24 months): continued improvement in joint comfort and function for most patients.

Repeat injections are rarely needed within the first two years.

Risks and side effects

Arthrosamid® has a favourable safety profile when delivered under ultrasound guidance.

Common (mild, self-limiting):

• Temporary swelling

• Mild joint discomfort

• Bruising at the injection site

Uncommon:

• Joint effusion (fluid build-up)

• Inflammatory flare (resolves within 1–2 weeks)

Rare:

• Joint infection (<0.1% risk)

• Persistent synovitis

Ultrasound guidance and strict sterile technique significantly reduce risk. Our clinic adheres to stringent infection control protocols.

What to expect on the day

Pre-assessment:

• Clinical exam and history

• Ultrasound scan of the knee

• Confirmation of eligibility

Injection procedure:

1. Ultrasound localisation to identify the joint space.

2. Local anaesthetic applied for comfort.

3. Arthrosamid® is injected into the synovial space under real-time guidance.

4. Compression and aftercare instructions provided.

Aftercare:

• Rest for 24–48 hours.

• Avoid strenuous exercise for 5–7 days.

• Gradual return to activities; walking encouraged.

Most patients resume daily routines within a few days.

Arthrosamid® vs other injection options

Treatment	Duration	Onset	Repeat Frequency	Inflammation Control
Arthrosamid®	12–24 mo	2–12 wks	Rarely needed	✔️ Strong effect
Corticosteroids	4–12 wks	24–72 hrs	Every 3–6 mo	✔️ Short-lived
Hyaluronic Acid	3–6 mo	1–2 wks	Every 6 mo	❌ Weak effect
PRP	6–12 mo	2–6 wks	Every 6–12 mo	✔️ Moderate
Conservative Care	Variable	Variable	Ongoing	❌ Minimal

Arthrosamid® offers the longest single-injection durability currently available for knee OA.

Cost and availability (private vs NHS)

Arthrosamid injection cost in private care:

Item	Typical Private Fee (GBP)
Initial Consultation & Scan	£150–£250
Arthrosamid® Injection	£2,000–£2,500
Includes Aftercare Support	✔️
Finance Options Available	✔️

While Arthrosamid cost may seem high initially, it often outweighs the repeat costs of steroids or hyaluronic acid over time.

Arthrosamid injection NHS availability:

Is Arthrosamid available on the NHS?
As of late 2025, Arthrosamid® is not routinely available on the NHS. Access may be possible through private referral or under specialist pain clinics in research settings.

We can advise you on referral letters or combined NHS-private pathways.

Real-world patient feedback

What do Arthrosamid reviews say?

Patients typically report:

• Reduced knee pain after 4–6 weeks

• Improved walking and stair use

• Delayed or avoided knee surgery

• Relief lasting 12–24 months

However, not every patient responds, and we’re transparent about that during your consultation.

Interested in Arthrosamid® injection near you?

We offer fast-track appointments with no referral required.

What to bring:

• Past imaging or MRI reports (if available)

• List of medications

• Comfortable clothing

Booking & timelines:

• Initial consultation within 5–7 days.

• Injection appointments are often available within 1–2 weeks.

• Same-day consultation + injection possible in select cases.

Book your appointment today using our online form or call us directly.

Disclaimer

This article is for informational purposes only and does not replace personalised medical advice. Please speak to a healthcare professional for individual recommendations.