Arthrosamid: A New Treatment for Knee Osteoarthritis Offering Longer Term Pain Relief

April 14th, 2024


Knee osteoarthritis (OA) is a debilitating condition affecting millions worldwide. It causes pain, stiffness, and reduced mobility, significantly impacting quality of life. While traditional treatments exist, a new option is gaining traction: Arthrosamid.

This blog post explores Arthrosamid, its mechanism of action, potential benefits, and its place in the management of knee OA.

What is Arthrosamid?

Arthrosamid is a single injection treatment for knee OA. It is an injectable polyacrylamide hydrogel (iPAAG) for intra-articular administration. It is a non-biodegradable, synthetic hydrogel composed primarily of water and a cross-linked polymer called polyacrylamide. This single-dose injection delivers long-acting and sustained pain relief, improving the quality of life for patients with knee osteoarthritis. Unlike hyaluronic acid injections, Arthrosamid offers a unique approach.


Intra-articular polyacrylamide hydrogel injection (iPAAG) in Arthrosamid® is made of 2.5% cross-linked polyacrylamide and 97.5% water.

  • Biocompatible: permeable to salts and organic molecules, the hydrogel can integrate with soft tissue
  • Viscoelastic: cross-linked chains of polymer allow flexible shear
  • Non-degradable: structural stability of hydrogel provides longevity of action

How Does Arthrosamid Work?

Healthy knee joints have smooth cartilage surfaces lubricated by synovial membrane and fluid. In OA, the cartilage deteriorates, the synovium becomes inflamed and the synovial fluid loses its viscosity. Arthrosamid addresses these issues:

Arthrosamid is the only approved injectable substance that integrates into the synovial tissue of the inner capsule and decreases joint stiffness, thereby diminishing pain and improving the function of the knee affected by QA. Its permanence means that it can provide long-term pain relief to treat knee OA.

Viscosupplementation: Upon injection, Arthrosamid acts like a scaffold, increasing the viscosity of the synovial fluid and improving joint lubrication.

Cushioning and Support: The hydrogel integrates with the joint capsule, providing a cushioning effect and reducing friction between bones.

Reduces Synovial Inflammation: Arthrosamid adheres to the synovial membrane and acts as a physical buffer and scaffold. This allows for the integration of a de novo layer of infiltrating synovial lining cells (Henriksen et al., 2018; Tnibar et al., 2017; Christensen & Daugaard, 2016).

Potential for Tissue Regeneration: Early research suggests Arthrosamid might create a favourable environment for cartilage regeneration.

Potential Benefits of Arthrosamid

Studies have shown promising results with Arthrosamid, including:

Pain Reduction: Patients reported significant pain relief lasting for extended periods compared to traditional options.

Improved Function: Increased knee mobility and flexibility allow for better daily activities.

Minimally Invasive: Arthrosamid is a single injection procedure with minimal recovery time.

Potentially Delays Surgery: By managing symptoms effectively, Arthrosamid might delay or avoid the need for knee replacement surgery

Who Can Benefit from Arthrosamid?

Arthrosamid might be a suitable option for patients with moderate knee OA who haven’t found sufficient relief with conservative measures like physical therapy or pain medication. It’s crucial to discuss candidacy with your doctor, considering factors like overall health and severity of OA.

Arthrosamid operates distinctly from traditional injections. Its efficacy in cases of severe, bone-on-bone arthritis is particularly noteworthy. Unlike other treatments that focus on cushioning between the bones, Arthrosamid targets the synovium – the soft tissue lining the joint. This approach is effective even in situations where there is minimal cartilage left, as it doesn’t rely on the space between bones for its mechanism of action.

Clinical Evidence

  • The clinical application of Arthrosamid (iPAAG) is safe and effective.
  • A stable and statistically significant change on all WOMAC subscales and WOMAC total over the 56-week observation period.
  • Undergone over 20 years of research and development.
  • A significant difference in change from baseline between Arthrosamid and Synvisc-One at 52 weeks.
  • Statistically significant reduction in pain maintained at 3 years.

3-year results for Arthrosamid from the IDA extension study presented at OARSI WORLD CONGRESS (17-20 March 2023). A study presented at the Orthopaedic Research Society International (OARSI) World Congress, in Denver (Colorado, USA) from 17-20th March 2023, has found that a single injection of 6 ml 2.5% polyacrylamide hydrogel, Arthrosamid, maintained a statistically significant reduction in pain in patients with knee osteoarthritis (OA) 3 years after treatment.

Important Considerations

It is important to have realistic expectations with Arthrosamid. Although the results can be astonishing, and it can significantly delay the need for a knee replacement, it is not a permanent solution for everyone. While research suggests a favourable safety profile, potential side effects like injection site pain and swelling can occur. Additionally, the cost of Arthrosamid might not be covered by insurance companies.

At Pain Spa, Dr. Krishna is highly experienced in the comprehensive management of osteoarthritis and knee pain. During your consultation, Dr. Krishna will discuss all available management options, including Arthrosamid, enabling you to make an informed decision about your treatment.


1.Bliddal, H., et al. (2021). Polyacrylamide Hydrogel Injection for Knee Osteoarthritis: A 6 Months Prospective Study. J Orthop Res Ther. 6(2). 1188. ISSN 2575-8241.

2.Henriksen, M., et al. (2018). Intra-articular 2.5% polyacrylamide hydrogel for the treatment of knee osteoarthritis: an observational proof-of-concept cohort study. Clin Exp Rheumatol. Nov-Dec;36(6):1082-1085. Epub 2018 Jul 18. PMID:

3. Data on file.

4. Bliddal, H., et al. (2022). One-year performance of polyacrylamide hydrogel vs. hyaluronic acid in age, BMI, and Kellgren-Lawrence subgroups: A subgroup analysis of a randomised study. Osteoarthritis and Cartilage Vol.30, Supplement 1, S373-S374.

5. Henriksen, M. et al. (2023). 3-year results from a prospective study of polyacrylamide hydrogel for knee osteoarthritis. Osteoarthritis and Cartilage, Vol 31(5): P682–683. DOI:10.1016/j.joca.2023.02.023