What is Arthrosamid®?
Arthrosamid® is an injectable polyacrylamide hydrogel: 2.5% cross-linked polyacrylamide and 97.5% water. It is given as a single 6 ml injection into the knee joint under ultrasound guidance.
Once injected, the gel integrates into the synovial membrane, the lining of the joint, where it forms a durable cushioning layer. Unlike hyaluronic acid, which the body absorbs over weeks to months, Arthrosamid® is not absorbed and does not need repeating on a schedule.
It has been approved for use in the United Kingdom and Europe since 2021.
Arthrosamid® reduces pain and stiffness. While it cannot rebuild cartilage or reverse osteoarthritis, it works to mitigate the forces and inflammation producing pain in osteoarthritis. Please note it is not a regenerative treatment. The gel is designed to stay in your knee permanently. That is what gives the lasting effect without further treatments. However, that also means it cannot currently be removed if you are unhappy with the result.
It has not been shown to be better than the alternatives. In the only trial comparing Arthrosamid® directly with hyaluronic acid, it performed as well but not better. What is different is duration: one treatment rather than repeated courses.
Why choose The Re:PAIR Clinic for Arthrosamid®?
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Every injection is ultrasound-guided, with needle position confirmed sonographically before delivery
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One-hour consultations, so there is time to decide properly
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Specialist-led assessment by a Sports and Exercise Medicine physician
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We follow a written protocol setting out who we will and will not treat
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We record structured outcome scores on every patient, and audit our own results
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CQC registered and inspected
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Integrated rehabilitation, including directed physiotherapy and orthotics where they will help
We assess you properly first, and we will tell you if we do not think Arthrosamid® is the right treatment for you.
What to expect during treatment
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Initial Consultation
A thorough assessment of your symptoms, lifestyle, examination and imaging to confirm suitability. -
The Procedure
You will be given a dose of preventative antibiotics with the procedure carried out under aseptic conditions using ultrasound guidance. Most patients describe the procedure as minimal discomfort rather than painful. -
Aftercare
You’ll be advised to avoid high-impact activities for a few days. Most patients resume normal walking the same day with a progressive return to usual activities within the week. -
Follow-up
We check your progress at 6 weeks and 3 months, with a validated outcome scoring tool for objective review.
When to seek urgent review
We advise all patients after an injection to please contact us, your GP/family practitioner or an emergency department straight away if you develop:
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A temperature, or feeling feverish and unwell
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A knee that becomes hot, very swollen and increasingly painful
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Redness spreading up or down the leg
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Pain getting worse rather than better after three days
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Inability to put weight through the leg
These can indicate infection in the joint. It is very uncommon, estimated at around one in ten thousand injections, but it is serious and needs treating quickly. Please do not wait to see whether it settles.
Fees
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New patient consultation, 60 minutes: £290
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Arthrosamid® injection, ultrasound-guided, including the product and your prophylactic antibiotic: £2,200
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Follow-up appointment, 30 minutes: £150
Klarna is available to spread the cost over three instalments with no additional fees.
Prices correct 1st July 2026. Subject to change. See our full pricelist here.
Available at our Harley Street clinic. We also offer tailored rehab add-ons and longevity consultations as part of our Move Well, Live Well Programme.
Book Your Appointment
To find out if Arthrosamid® is right for you, call us on 020 8050 0393, email admin@therepairclinic.co.uk or click here to book your consultation.
FAQs
How is it different from a steroid or hyaluronic acid injection?
Steroid injections give short-term relief, typically weeks to a few months. Hyaluronic acid is absorbed over months and courses are usually repeated. Arthrosamid® is not absorbed, so a single treatment can give benefit over years. In direct comparison against hyaluronic acid it performed as well, not better. The advantage is duration.
How soon will I feel better?
Improvement usually builds over four to twelve weeks rather than appearing straight away, with continued gains reported to around six months. Some people notice little change, and we cannot predict who in advance.
How long does it last?
Cohort follow-up has reported sustained benefit out to five years, ongoing studies are looking at large population data beyond that.
Will I need it again?
Often not, given the duration of effect. If your response is partial, we would reassess after around 12 months and discuss the options, which may include a further injection, a different treatment, or surgical referral.
Will it save me from a knee replacement?
Arthrosamid® treats pain. It does not alter the structure of the joint or change how the arthritis progresses. Some people find it buys them time. Some go on to have a replacement anyway. If you do, presence of the gel is not known to alter surgical outcomes.
Can it be removed?
No. It is non-biodegradable and integrates into the joint lining.
Do I need antibiotics?
Yes, a single dose before the injection at your consultation. This is specific to Arthrosamid® and is because it is a permanent implant.
Can I have both knees done?
It depends on your assessment. We will discuss it at your consultation.
Is it available in the United States?
No. Arthrosamid® is not approved by the FDA and is not available at any US clinic. We see a number of patients who travel to us for this reason.
Arthrosamid® is a CE-marked Class III medical device. Individual results vary and no clinical outcome is guaranteed. Arthrosamid® is a symptomatic treatment and is not disease-modifying. The Re:PAIR Clinic is registered with the Care Quality Commission.
How does Arthrosamid® work?
Once injected, the gel becomes incorporated in the synovial membrane, where it forms a lasting cushioning layer within the joint lining.
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Non-surgical — an outpatient procedure under local anaesthetic, with no general anaesthetic and no incision
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One injection — cohort follow-up has reported sustained benefit out to five years. We have longer term case studies but await data beyond 5 years in large populations
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Not absorbed — unlike hyaluronic acid, the gel is not broken down. This is what makes the effect last, and it is also why it cannot be removed
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Ultrasound-guided — we confirm the needle is correctly inside the joint before delivering the gel
Improvement usually builds over four to twelve weeks rather than appearing straight away. Some people may notice little change, and we cannot fully predict who in advance.
Who is Arthrosamid® for?
Arthrosamid® may be appropriate if you have:
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osteoarthritis of the knee
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had knee pain for three months or more
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not benefitted from simple conservative management steps
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are looking for symptom control
It is not suitable if you have
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any active infection, whether in the knee, elsewhere in the body, or in the skin over the joint
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a knee replacement, partial replacement, or any metalwork in that knee
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a known allergy to polyacrylamide hydrogel
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are pregnant or breastfeeding
We would want to discuss it carefully with you if
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Your arthritis is very advanced with significant deformity
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Your main problem is the knee locking or giving way rather than pain
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You have an inflammatory arthritis such as rheumatoid, or a crystal arthritis such as gout
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You have had a steroid injection into that knee in the last three months, or any injection in the last four weeks
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You take anticoagulants or have a bleeding disorder
If you are already listed for a knee replacement, we do not give Arthrosamid® within six months of surgery. Because it is an implant, injecting close to an operation may increase infection risk. Please tell us if surgery is already planned.
