Knee osteoarthritis · Injection information
Arthrosamid
Understanding a longer-lasting hydrogel injection for knee arthritis.
How does it work?
Arthrosamid is a non-absorbable polyacrylamide hydrogel injected into the knee joint. It becomes incorporated into the joint lining and is intended to improve symptoms of osteoarthritis. It is different from a steroid or hyaluronic acid injection.
It does not regrow cartilage or reverse arthritis. The material remains in the joint, so the decision requires a discussion about its permanence as well as possible symptom relief.
Could it be appropriate for me?
A knee assessment should establish the diagnosis, the impact on your life and what treatment you have already tried. Exercise, physiotherapy, appropriate weight management and pain relief remain important options.
Symptoms that substantially affect your quality of life despite non-surgical treatment may warrant a discussion about knee replacement. An injection should not delay an appropriate surgical assessment.
What does the evidence show?
A randomised study compared polyacrylamide hydrogel with hyaluronic acid and assessed symptoms over one year. It was an active-treatment comparison, not a placebo-controlled trial. Improvements reported in studies do not establish that every patient will benefit.
A September 2026 review in the British Orthopaedic Association’s journal highlighted limited supporting evidence and uncertainty about long-term effects of a permanent material. It reported no placebo-controlled Level I evidence. A lasting result cannot be promised.
Read the randomised study and 2026 review of osteoarthritis injections.
What happens during treatment?
Where offered and appropriate, treatment is usually delivered as an outpatient injection. The treating clinician explains local anaesthetic, imaging guidance and aftercare. The manufacturer recommends antibiotics before injection to reduce infection risk.
Follow the treating team’s instructions on activity and follow-up. Improvement may be gradual, and some people do not experience useful relief.
Risks and precautions
Possible problems include pain, swelling and infection. Tell the clinician about infections, skin problems, allergies, medicines and conditions affecting your immune system. A permanent implant needs particular consideration before treatment.
Inform clinicians about the injection before future surgery or dental procedures. A hot, increasingly swollen or very painful knee, especially with fever or feeling unwell, needs urgent medical assessment.
Read the manufacturer’s patient safety information.
Availability, fees and insurance
This page provides information; current availability at your chosen hospital must be confirmed with the secretary. A consultation does not commit you to treatment.
Ask for a complete quotation and check any insurance cover before proceeding. The treatment code finder can help with an enquiry, but a code is not confirmation of cover.
Ask the secretaryCompare your options
Read about exercise, medicines and other knee injection options, or book a knee assessment with Mr Mussa to discuss what is appropriate for you.
