Arthrosamid Knee Injection FAQs: Benefits, Suitability, Risks & Recovery
- Dec 5, 2024
- 7 min read
Updated: Jul 21
Arthrosamid® is a single-injection, non-absorbable hydrogel implant used to treat symptoms of knee osteoarthritis in adults. It may reduce pain and improve function for some patients, but it does not work for everyone. This guide explains the evidence, suitability, risks, aftercare and current ACTIVATE costs in London and Kent.
Last clinically reviewed by Dr Mustafa Alnaib: 21 July 2026.
Arthrosamid knee injection at a glance
Indication: symptomatic treatment of adult knee osteoarthritis.
Product: 97.5% sterile water and 2.5% cross-linked polyacrylamide hydrogel.
Dose: 6 mL injection into the knee joint.
Procedure: outpatient treatment using local anaesthetic and ultrasound guidance at ACTIVATE.
Recovery: gentle movement is encouraged; avoid strenuous or high-impact activity for at least 48 hours.
Current ACTIVATE price: £2,770 for one knee, plus the consultation
Locations: Maidstone and Kings Hill in Kent, and Kensington in London.
What is an Arthrosamid knee injection?
Arthrosamid is a non-absorbable hydrogel made from 97.5% sterile water and 2.5% cross-linked polyacrylamide. A recommended 6 mL dose is injected into the knee joint for symptomatic treatment of adult knee osteoarthritis. The hydrogel becomes integrated with the synovial tissue and remains in the knee.
Arthrosamid is not a steroid, hyaluronic acid, cartilage-regrowing treatment or cure for osteoarthritis. Its purpose is symptom relief.
How does Arthrosamid work?
After injection, the hydrogel disperses in the joint fluid and becomes integrated into the synovial lining. It is intended to provide durable symptom relief, but it does not replace cartilage or reverse osteoarthritis.
Does Arthrosamid really work?
Clinical studies in people with moderate-to-severe knee osteoarthritis have reported improvements in pain and function after a single injection. A randomised trial found Arthrosamid comparable to hyaluronic acid at one year. Follow-up reported that improvements were sustained in some participants for up to five years.
These findings do not mean that everyone will benefit. Arthrosamid should therefore be discussed as one option within shared decision-making, not as a guaranteed solution.
What is the success rate of Arthrosamid?
A clinician cannot predict your result from a headline percentage alone. Your diagnosis, osteoarthritis severity, other causes of knee pain, previous treatment and goals all matter.
Is Arthrosamid better than hyaluronic acid?
They are different products, and the right option depends on the patient. Arthrosamid is non-absorbable and integrates with synovial tissue, whereas hyaluronic acid is absorbable.
How long does Arthrosamid last?
Published follow-up now extends to five years in some study participants. That does not mean every injection works for five years. The size and duration of benefit vary, and evidence for repeat dosing is more limited. Recurrent symptoms should be reassessed rather than assuming another injection is appropriate.
How soon might I notice an improvement?
Some patients notice improvement within a few weeks, but maximum benefit may take up to 12 weeks. The timing and degree of improvement vary.
Who may be suitable for Arthrosamid?
Arthrosamid is intended for adults with symptomatic knee osteoarthritis. A clinician should first confirm that osteoarthritis is the main source of pain and review your examination, imaging, previous treatments, general health and treatment goals. It is not a general treatment for every cause of knee pain
Who should not have Arthrosamid?
According to current manufacturer safety information, Arthrosamid must not be injected:
through skin with active disease or infection, or into a knee that is infected or severely inflamed;
while a previous absorbable intra-articular product, such as hyaluronic acid, is still expected to be present;
after another non-absorbable injectable or implant in the same knee;
after knee replacement or when other foreign material is present in the knee;
within six months of knee arthroscopy; or
during uncontrolled haemophilia or uncontrolled anticoagulation treatment.
Extra caution is required with autoimmune disease, immunosuppression, a compromised immune system, uncontrolled diabetes, infection elsewhere in the body, major dental work or another invasive procedure. Safety and effectiveness have not been established for people under 18, pregnant or breastfeeding patients, people with a BMI of 35 kg/m² or above, or doses above 6 mL.
Can I have Arthrosamid after other knee injections?
Possibly, but timing and product type matter. A previous absorbable injection must be allowed to absorb, and Arthrosamid should not be used after another non-absorbable implant in the same knee. Tell your clinician the exact product you received and the date of every previous injection.
Can Arthrosamid be used in the hip, ankle or other joints?
Its intended use is the symptomatic treatment of adult knee osteoarthritis. Use in the hip, ankle or another joint is outside that intended indication and should be treated as off-label or investigational, with different evidence and risks.
What are the risks and side effects?
Reported effects include mild-to-moderate injection-site or joint pain and swelling during the first weeks to months; these are generally temporary. A Baker’s cyst may form or swell.
Infection is rare but requires urgent treatment. Contact the clinic promptly if your knee becomes hot, red, increasingly painful or markedly swollen, or if you feel feverish or unwell. Tell future healthcare and dental professionals that you have a permanent implant in the knee, because preventive antibiotics may need to be considered before some procedures.
What happens during an ACTIVATE Arthrosamid appointment?
The injection procedure usually takes about 15–30 minutes, although the full appointment may take longer. At ACTIVATE, an oral antibiotic is provided 1–2 hours beforehand as part of infection prevention. The knee is assessed, local anaesthetic is used and the injection is delivered under ultrasound guidance.
Does the procedure require a general anaesthetic?
No. At ACTIVATE it is performed as an outpatient procedure using local anaesthetic and ultrasound guidance. You may still feel pressure or temporary discomfort
What should I wear?
Wear loose, comfortable clothing that gives easy access to the knee, such as shorts or wide-legged trousers.
What is the aftercare for Arthrosamid?
Keep gently mobile after the injection, but avoid strenuous or high-impact activity for at least 48 hours and follow your personalised rehabilitation plan. Your clinician may tailor this advice to your health, work and activity level.
Can I drive after an Arthrosamid injection?
Arrange for someone to drive you home. At ACTIVATE, we advise avoiding driving for 24 hours and until you can safely control the vehicle, perform an emergency stop, and are not limited by pain, swelling or medication. Follow the personalised advice given at your appointment.
When can I return to normal activity?
Light daily movement can usually begin immediately, but the return to work, exercise and sport depends on symptoms and your clinician’s advice. Build activity gradually.
How much does Arthrosamid cost at ACTIVATE?
At ACTIVATE, the current package for one knee is £2,770 plus the initial consultation: £180 in Kent or £300 in London. The package includes the injection, ultrasound and a personalised digital physiotherapy programme that can be performed at home or at the gym.
Prices were checked are correct as of July 2026. Please confirm the current total when booking.
Is Arthrosamid covered by private insurance?
Arthrosamid is commonly self-funded, but cover varies by insurer and policy. Ask your insurer for written confirmation before treatment. ACTIVATE offers flexible payment options for eligible self-paying patients; any instalment arrangement is subject to the applicable terms and approval.
Is Arthrosamid available through the NHS?
Arthrosamid is not routinely funded as a standard NHS treatment as of July 2026. ACTIVATE offers Arthrosamid as a private, self-pay treatment.
What are the alternatives to Arthrosamid?
Alternatives depend on the severity of symptoms and your goals. They may include education, targeted exercise and physiotherapy, weight management where relevant, pain medication, corticosteroid or hyaluronic acid injections, and surgical review for advanced disease. A consultation should compare expected benefits, uncertainties, risks, recovery and cost.
How is Arthrosamid different from a steroid injection?
A corticosteroid is an anti-inflammatory medicine generally used for shorter-term symptom relief. Arthrosamid is a permanent, non-steroid hydrogel implant intended for longer-lasting symptom control. Neither option is guaranteed, and the appropriate choice depends on diagnosis, risks, previous treatment and patient preference.
Can Arthrosamid delay knee replacement?
It may help some patients manage symptoms while they defer a decision about surgery. It does not reverse the structural changes of osteoarthritis.
What happens if Arthrosamid does not work for me?
Your clinician should assess the diagnosis, current symptoms and goals before recommending another treatment. Options may include rehabilitation, medication, another type of injection or surgical review.
Is Arthrosamid available in the United States?
As of July 2026, Arthrosamid is not approved by the US Food and Drug Administration and is not routinely available in the United States. ACTIVATE can offer international patients a complimentary virtual suitability review and X-ray assessment before travel. Treatment is only arranged after clinical review.
Email alnaib@mskclinic.co.uk or contact ACTIVATE on WhatsApp at +44 7369 222132.
What ACTIVATE patients have said
“Dr Alnaib is very patient and professional. I received injections of Arthrosamid in both knees. It’s been a month and my right knee feels 98 percent. My left knee has always been more problematic, and it still creates some pain. I have no trouble walking. I am hopeful that it will continue to improve.” ★★★★★
“Excellent doctor, patient and helpful and efficiently carried out procedures.” ★★★★★
Testimonials describe individual experiences and do not predict another patient’s result.
Book an Arthrosamid assessment in London or Kent
ACTIVATE Musculoskeletal Clinic offers private knee osteoarthritis assessment and ultrasound-guided injections in Maidstone, Kings Hill and Kensington. In most patients, the injection can be carried in the same day, after 1-2 hours from having the prescribed antibiotics.
Clinical review and evidence sources
Clinically reviewed by: Dr Mustafa Alnaib, MBChB, MRCS, MSc, FEBOT, orthopaedic surgeon, musculoskeletal doctor and Clinic Director at ACTIVATE Musculoskeletal Clinic.
This article supports shared decision-making and does not replace an individual medical assessment. Product information, evidence, availability and prices can change.