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Arthrosamid® injection

A safe, effective, minimally invasive treatment for knee osteoarthritis to reduce knee pain and get you moving again.

This non‑surgical treatment delivers long‑lasting relief from a single injection, with benefits shown to last up to five years, supported by leading orthopaedic experts throughout your recovery.

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Mr Chipperfield's outpatient services, London
Mr Chipperfield's London outpatient services

Meet with our Consultant Orthopaedic Surgeon, Mr Alex Chipperfield in London’s Harley Street district as an outpatient.

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Whether you're thinking about treatment or want to know what to expect during your time with us, our regular patient webinars are a great way to find out more.

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Arthrosamid® injections at a glance

Here's what to expect from your Arthrosamid® injection and the recovery process.

Procedure time

Five to 10 minutes

Hospital stay

Three hours

Full weight bearing

On the day of surgery

Shower

12 hours

Driving

Same day (but you'll need someone to drive you home)

Air travel

No restriction

Full recovery

Up to three months

Time off work

No restriction

What are Arthrosamid® injections?

Arthrosamid® is an innovative, injectable gel used as an innovative treatment for knee pain and other symptoms of knee osteoarthritis - without the need for surgery.

A single Arthrosamid® injection [1], performed in our Ambulatory Care Unit (ACU) under local anaesthetic, cushions and lubricates your knee joint, reducing stiffness and pain for longer than other types of injection.

Download the Arthrosamid® brochure

How do Arthrosamid® injections work?

Your consultant will give you an oral antibiotic one to two hours before the procedure to reduce the risk of infection.

They’ll swab the area and use a local anaesthetic to numb the skin around the injection site. Next, they’ll insert the needle with the first syringe of Arthrosamid® into your knee’s synovial cavity, using ultrasound to guide them. You may notice that the sensation is different as the gel is thicker than most other injectables.

The needle will stay in place, and your consultant will inject five further doses of Arthrosamid® gel. The Arthrosamid® will disperse within the synovial fluid and start to bind with the synovial tissue [3].

Your consultant will remove the needle, swab your knee, and cover the wound with a plaster.

How much do Arthrosamid® injections cost?

View our prices for self-pay patients and Benenden Health members. Take advantage of payment plans through our trusted partner, Chrysalis Finance, and spread the cost of your treatment. Fit your repayments into your monthly budget rather than having to find the full cost at the time of your treatment.

Procedure type
Initial consultation price
Treatment price*
Monthly cost**
Member discount
Arthrosamid® injection - one knee
£210
From £2,956
From £71.47
10%
Arthrosamid® injection - both knees
£210
From £4,983
From £120.48
10%
Arthrosamid® injection - one knee
£210
From £2,956
From £295.60
10%
Arthrosamid® injection - both knees
£210
From £4,983
From £498.30
10%
Arthrosamid® Injections
Arthrosamid® Injections (0% over 10 months)
Arthrosamid® Injections
Arthrosamid® injection - one knee
Initial consultation price
£210

Treatment price*
From £2,956

Monthly cost**
From £71.47

Member discount
10%

Arthrosamid® injection - both knees
Initial consultation price
£210

Treatment price*
From £4,983

Monthly cost**
From £120.48

Member discount
10%

Arthrosamid® Injections (0% over 10 months)
Arthrosamid® injection - one knee
Initial consultation price
£210

Treatment price*
From £2,956

Monthly cost**
From £295.60

Member discount
10%

Arthrosamid® injection - both knees
Initial consultation price
£210

Treatment price*
From £4,983

Monthly cost**
From £498.30

Member discount
10%

About Arthrosamid® injections

Consultant Orthopaedic Surgeon, Mr Alex Chipperfield, talks about knee osteoarthritis and how Arthrosamid® injections can reduce knee pain and get you moving again

Our Arthrosamid® patient success stories

Jane I Benenden Hospital patient

“I think it is a wonder gel. It is well worth investing in it, even with late-stage arthritis as in my case. I think it should be the first line of defence before surgery."

Jenny | Benenden Hospital patient

I’ve wholeheartedly recommended the Arthrosamid® injection to four of my friends, two of which have even had their procedures!"

Eunice | Benenden Hospital patient

"For early-stage osteoarthritis, I highly recommend the Arthrosamid® gel injection" says Eunice.

FAQs

What is knee osteoarthritis? +

Osteoarthritis is progressive damage of the cartilage that cushions the ends of your bones. The cartilage wears away so that bone rubs against bone, causing inflammation and pain.

Knee osteoarthritis is a common condition that affects the knee joints, causing pain and stiffness that can affect your ability to walk and exercise.

What is synovitis? +

Synovitis, or synovial pain, is a common symptom of knee osteoarthritis. It’s caused by inflammation of the synovial tissue, which is the lining of the knee joint. Synovitis is also associated with a more rapid loss of cartilage if you already have osteoarthritis.

Treating synovitis in the early stages of osteoarthritis may slow down its progression [4].

Why would I have Arthrosamid® Injections? +

There are several reasons you might choose to have an Arthrosamid® injection:

  • Painkillers and lifestyle modifications haven’t eased your knee pain
  • Knee replacement surgery may not be right for you; you may be too young or have a medical condition which prevents you from having surgery
  • You may not want a knee replacement, for example if you work in a job where you’re kneeling regularly

Your Clinician will review your medical history, including your level of pain. They may arrange an X-ray to establish the grade of osteoarthritis and will discuss your options at your appointment.

Who can’t have Arthrosamid® injections? +

Your Consultant will discuss your suitability for Arthrosamid® treatment at your initial consultation and any reasons why you might not be able to have the procedure. These include:

  • If you have an infection on or near the injection site
  • If you have haemophilia or take anticoagulants
  • If you have an autoimmune condition, such as Multiple Sclerosis, Addison’s, or Coeliac Disease
  • If you’re had a knee arthroscopy in the past six months
  • If you have a foreign body in your knee
  • If you’re pregnant or breastfeeding
  • If your diabetes is poorly controlled
  • If you’re planning to have major dental work
Can I have Arthrosamid® injections in both knees? +

It’s possible to have Arthrosamid® injections in both knees, but you should discuss this with your Consultant.

Are there any Arthrosamid® side effects? +

Clinical trials have reported no serious side effects following an Arthrosamid® injection [5,6].

Are Arthrosamid® injections available on the NHS? +

Arthrosamid® isn’t currently available on the NHS.

How long do the Arthrosamid® injections take? +

Treatment usually takes between 20 and 30 minutes.

What should I expect after the Arthrosamid® injections? +

Immediately after the Arthrosamid® injection, we’ll invite you to rest until you feel ready to walk again. Your knee might feel a little uncomfortable as the anaesthetic wears off.

You might experience joint pain and a sensation of swelling in the joint, but this shouldn’t last more than a couple of weeks. If your knee becomes red, hot, very swollen, or more painful, please contact your Consultant immediately.

When can I return to my normal activities? +

You shouldn’t drive for 24 hours after your injection, so please arrange a lift home.

You should keep moving after your Arthrosamid® injection, but we’d recommend that you take it easy to begin with and avoid any high impact activities. You should be able to return to your normal activity within three months.

How successful are Arthrosamid® injections? +

Patients who are under 70 reported almost an 80% positive response rate following treatment with Arthrosamid®.

How long does Arthrosamid® last? +

Your injection should last around five years [2], but there’s no reason you couldn’t have another injection after this time if your knee pain has returned. You should discuss this with your Consultant or GP.

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Our consultant orthopaedic surgeons

Alex Chipperfield
ONLINE BOOKING AVAILABLE

Alex Chipperfield

Consultant Orthopaedic Surgeon

Language(s): English

Location(s): Kent, London

Mr Chipperfield's specialties include hip and knee replacement, including ROSA knee, revision hip and knee replacement, Arthrosamid® injections and more.

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Richard Goddard
ONLINE BOOKING AVAILABLE

Richard Goddard

Consultant Orthopaedic Surgeon

Language(s): English

Location(s): Kent

Mr Goddard's specialties include total knee replacement and Signature total knee replacement.

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Mark Jones
ONLINE BOOKING AVAILABLE

Mark Jones

Consultant Orthopaedic Surgeon

Language(s): English

Location(s): Kent

Mr Mark Jones specialises in knee replacement and knee surgeries, including ROSA knee, as well as Arthrosamid® injections.

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Matthew Oliver
ONLINE BOOKING AVAILABLE

Matthew Oliver

Consultant Trauma and Orthopaedic Surgeon

Language(s): English

Location(s): Kent

Mr Oliver's specialties include total hip and knee procedures, including Arthrosamid injections and robotic-assisted total knee replacement.

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Kumar Reddy
ONLINE BOOKING AVAILABLE

Kumar Reddy

Associate Specialist Surgeon

Language(s): English

Location(s): Kent

Mr Reddy specialises in total hip and knee replacements, revision joint replacements, ACL reconstruction, and more.

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Raman Thakur
ONLINE BOOKING AVAILABLE

Raman Thakur

Consultant Orthopaedic Surgeon

Language(s): English

Location(s): Kent

Mr Thakur's specialties include hip and knee replacement, ACL reconstruction and general orthopaedics.

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William Dunnet
ONLINE BOOKING AVAILABLE

William Dunnet

Consultant Orthopaedic Surgeon

Language(s): English

Location(s): Kent

Mr Dunnet's specialities include hip surgery, patella realignment and lower limb procedures.

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Book your Arthrosamid® consultation today

It's easy to find out more about treatment for knee pain at our Kent hospital or London outpatients centre by giving us a call.

References

  1. Bliddal, H, Overgaard, A, Hartkopp, A et al. (2021) Polyacrylamide Hydrogel Injection for Knee Osteoarthritis: A 6 Months Prospective Study. J Orthopaedic Research and Therapy, 6 (2), 1188. ISSN 2575-8241.
  2. Bliddal, H., et al. (2025) A Prospective Study of Polyacrylamide Hydrogel Injection for Knee Osteoarthritis: Results From 5 Years After Treatment. Presented at WCO-IOF-ESCEO 2025.
  3. Christensen, L., et al. (2016). Synovial incorporation of polyacrylamide hydrogel after injection into normal and osteoarthritic animal joints. Osteoarthritis and Cartilage. Vol 24(11):1999-2002. DOI:10.1016/j.joca.2016.07.007.
  4. Mathiessen, A., et al. (2017). Synovitis in osteoarthritis: current understanding with therapeutic implications. Arthritis research & therapy. Vol 19(1):18. DOI:10.1186/s13075-017-1229-9.
  5. Bliddal, H., Beier, J., Hartkopp, A. et al. Effectiveness and safety of polyacrylamide hydrogel injection for knee osteoarthritis: results from a 12-month follow up of an open-label study. J Orthop Surg Res 19, 274 (2024). https://doi.org/10.1186/s13018-024-04756-2
  6. Overgaard, A., et al. (2019). Safety of intra-articular polyacrylamide hydrogel for the treatment of knee osteoarthritis symptoms: A retrospective case series. Clin Ortho Adv Res. Osteoarthritis and Cartilage. Vol 30(1): S370-71. DOI:10.1016/j.joca.2022.02.497.
Page last reviewed: 23 April 2026