Safety & side effects

Arthrosamid / Safety & Side Effects

Knowing what to expect. Knowing when to call.

Understand what can happen after treatment, the precautions we take and how to get advice.

Check symptoms and next steps Our treatment precautions

Clear advice. A team to contact.

Already had treatment and concerned?

Use the clinical contact details in your written aftercare. For severe or rapidly worsening symptoms, seek urgent same-day medical assessment.

Check action guide NHS 111

What you notice. What to do next.

A practical guide to post-treatment symptoms.

Mild and settling

Mild temporary soreness, swelling or stiffness can occur in the days following injection as your knee settles.

Action

Follow your individual written aftercare and take things gently. If you are unsure or symptoms are not improving, contact the clinical team.

Worsening or concerning

Increasing pain or swelling, a hot or red knee, discharge from the injection site, fever, chills or feeling generally unwell.

Action

Contact the clinical team promptly for advice.

If the clinic is unavailable, seek advice via NHS 111 or an urgent GP appointment.

Severe or rapidly worsening

Severe or rapidly worsening pain, marked swelling, or sudden inability to bear weight on the knee.

Action

Need urgent same-day assessment.

Contact urgent GP, NHS 111, or attend A&E as needed. Do not wait for a routine clinic callback.

Call 999 for difficulty breathing, sudden swelling of the mouth, tongue or throat, or collapse.

General clinic enquiries: 0330 043 2571 (Not an emergency line)

What has been reported after knee treatment

Temporary pain, swelling, effusion and stiffness have been reported in the knee osteoarthritis cohort and product-safety information. A mild reaction should begin to settle; increasing symptoms need review using the advice above.

Joint infection is a recognised serious risk. Because the hydrogel is non-absorbable, a complication can be more difficult to manage and may need prolonged treatment or surgery. Study observations do not give a precise risk estimate for an individual patient.

Read the published study and safety context →

Care built around the treatment.

IV antibiotics before every Arthrosamid injection at LCC.

Health & allergy review

Thorough medical checklist

Sterile preparation

Sealed clinical trays

Ultrasound guidance

Real-time ultrasound guidance

Precautions reduce risk but do not make the procedure risk-free.

Before we treat your knee

Please tell the clinical team about any changes to your health before your visit.

Current medicines and known allergies
Previous reactions to medical treatments
Any new illness or skin infection near the knee
Previous knee procedures or injections

Do not stop prescribed medicines unless the clinician explicitly advises you to.

Scans are submitted through the patient portal before your consultation.

What This Means for You

Your consultation should cover potential benefits, known risks, uncertainties, alternatives and how treatment fits your knee and goals. We discuss both supportive evidence and relevant complications literature, and do not recommend treatment where the risk–benefit balance is unfavourable.

Ask the team if you would like help understanding the historical Aquamid literature. Cosmetic-use reports and modern knee-injection studies need to be considered separately; neither should be hidden or treated as directly interchangeable.

Prepare for a suitability discussion →

Questions to ask any clinic before Arthrosamid®

Use these questions to check the safeguards around your care, alongside the discussion of possible benefit.

Assessment and imagingConfirm your diagnosis, imaging review, previous care and alternatives before committing to an injection. A provider should explain when treatment is unsuitable.
The treating clinicianAsk who assesses you and who injects, their relevant experience and how any treatment-volume figure is defined and dated.
Guidance and infection precautionsAsk about real-time ultrasound, sterile preparation and the antibiotic route, timing and allergy checks. No precaution eliminates risk.
Support after treatmentConfirm the review appointment, contact details for a flare, urgent escalation route and any additional fees.
Realistic claimsBe cautious about guaranteed relief, permanent cures, cartilage regeneration or promises to prevent surgery. Ask for published evidence in the right clinical context.

Our IV antibiotics and infection-prevention pathway →

Risks to discuss

Important considerations we will review with you.

Temporary symptoms

Mild soreness, stiffness, or swelling may occur shortly after the procedure as the joint settles.

Joint infection

A serious but rare risk with any joint injection, requiring prompt medical assessment and intervention.

Reactions to medicines

Potential reactions to local anaesthetic, IV antibiotics, or the hydrogel are reviewed against your medical history beforehand.

What Has Been Reported in the Medical Literature

There are published papers describing complications related to polyacrylamide hydrogels, most notably under the brand name Aquamid (a chemically similar product from the same manufacturer group, marketed under a different label).

These reports primarily relate to:

Cosmetic and soft-tissue injections
Large injection volumes
Non-joint tissues (breast, fat)
Long-term follow-up (many years)

Reported complications include:

Chronic inflammation
Infection (delayed presentations)
Nodules or firmness
Migration of material
Need for surgical removal

For transparency, patients who wish to explore this literature in detail are encouraged to read the published review article on Aquamid complications.

Why Context Matters

It is important to understand that clinical outcomes are heavily influenced by the environment and method of application:

The knee joint is a very different biological environment from soft tissue.

Arthrosamid® for knee osteoarthritis is delivered:

In much smaller volumes
Inside the joint, not under the skin
Using image-guided techniques

Most published complication data relate to historic cosmetic use, not modern intra-articular knee treatment.

"That said, differences in indication do not eliminate risk, and this literature reinforces why careful patient selection, technique, and follow-up are essential."

Aftercare

Clinic contact

Follow-up

Keep your aftercare advice close

Your written aftercare includes direct clinic contact details and specific recovery steps. A standard review is planned around 6 weeks, but please seek advice earlier if you are concerned.

Download Aftercare PDF Read recovery timeline

Common questions

Is swelling always an infection?

No, mild temporary swelling can happen as the joint settles. However, worsening swelling, severe pain, or a hot knee requires prompt medical advice, as an online guide cannot diagnose you. Learn more about joint infection or visit NHS Septic Arthritis.

Why IV antibiotics?

Providing intravenous (IV) antibiotics before the procedure is a standard preventive protocol at LCC to reduce the risk of joint infection associated with injections.

What if I have an antibiotic allergy?

Tell the clinical team well in advance. Your allergies will be reviewed with the clinician to find a safe approach. Do not substitute or self-medicate. See NHS Anaphylaxis guidance.

Is Arthrosamid® safe?

Arthrosamid has recognised temporary reactions and less common complications. Ultrasound guidance, sterile technique, antibiotic cover and careful selection support safe practice but do not eliminate risk. Clinical assessment is essential because product-specific contraindications and reasons to postpone must be checked before treatment.

What are the most common Arthrosamid® side effects?

The most commonly reported side effects are short-term injection-site pain, mild swelling, warmth and joint stiffness after treatment. A temporary flare should trend towards settling. The clinic reviews patients at six weeks and earlier when symptoms warrant; worsening pain, heat, redness, swelling, fever or systemic illness needs prompt advice.

What are the more serious risks of Arthrosamid®?

Joint infection is a serious potential complication. Other reported problems include a persistent inflammatory reaction or symptoms requiring further assessment. The clinic's protocol reduces avoidable risk but cannot make risk zero. Read the dedicated Arthrosamid infection risk page for a full explanation of how London Cartilage Clinic minimises infection risk.

Is Arthrosamid® reversible?

Arthrosamid is non-absorbable and intended to remain in the joint. It is not a temporary injectate that the body is expected to clear, and removal can be difficult if a serious complication occurs. That makes selection, infection prevention and informed consent especially important.

Can Arthrosamid® damage cartilage?

Arthrosamid® is a hydrogel that acts on the synovium, not a regenerative product, and it does not regenerate cartilage. The available symptom-outcome evidence does not establish that it changes structural progression in either direction. Osteoarthritis can continue to progress after treatment.

Who should not have Arthrosamid®?

Manufacturer professional information states that it should not be used where there is an active joint infection or where knee surgery or arthroscopy has occurred within the defined product-safety window. Infection elsewhere, broken skin near the site, acute illness, medicine allergies and planned procedures can also require postponement and clinician review. See the Arthrosamid® suitability self-assessment.