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New 3 year data demonstrates the long-term efficacy of Arthrosamid® (2.5% injectable polyacrylamide hydrogel)

New 3-year data for Arthrosamid®(2.5% injectable polyacrylamide hydrogel) from the IDA extension study presented at OARSI World Congress (17-20 March 2023).

A study presented at the Osteoarthritis 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 treatment1.

Previously reported data from the prospective open label study “IDA” had demonstrated Arthrosamid’s effect in reducing pain at 6 months2, which was maintained at 12 months3 and 2 years4. This trial, together with extensive safety and performance data generated for the injectable polyacrylamide hydrogel (iPAAG®) technology over 2 decades, led to Arthrosamid’s European regulatory CE approval for the symptomatic treatment of patients with knee OA in 2021.

The “IDA” study of 49 participants was initially planned for 6 month and 1 year outcomes but was extended to assess the long-term safety and efficacy of Arthrosamid for up to 5 years after treatment. The research team from Denmark is now delighted to be able to release the 3-year data which provides promising evidence that patients can experience the benefits of their Arthrosamid treatment, reducing pain and improving mobility in the knee affected by OA, for a significant period of time.

This prospective, multi-centre study involved patients with knee OA receiving a single intra-articular injection of 6 mL Arthrosamid®. The study included 49 participants (31 females) with an average age at treatment of approximately 70 years (range 44 – 86 years). 29 participants completed the extended 3-year follow-up.

Using the WOMAC (The Western Ontario and McMaster Universities Osteoarthritis Index) scale, widely used in the evaluation of hip and knee osteoarthritis, the results of the IDA study showed clinically relevant and highly statistically significant decreases from baseline to 3 years for each of the three WOMAC subscale scores (physical pain, stiffness and function) and the PGA (Patient Global Assessment), which is a self-reported measure reflecting the patient’s own assessment of the impact of their condition.

New 3 Year Data from IDA extension study - Arthrosamid®
New 3-year data for Arthrosamid® (2.5% injectable polyacrylamide hydrogel) from the IDA extension study presented at OARSI World Congress (17-20 March 2023).

Arthrosamid® is the only intra-articular 2.5% injectable polyacrylamide hydrogel (iPAAG) treatment approved in Europe that is permanently integrated in the synovial tissue of the inner capsule5 decreasing joint stiffness, reducing pain, and improving the function of the knee affected by osteoarthritis2. The physical mode of action allows Arthrosamid to provide long-term relief for patients with knee OA.1

Pioneered by polyacrylamide hydrogel technology specialists, Contura Orthopaedics Ltd, Arthrosamid® was developed and designed to be a novel, minimally invasive, and durable treatment for knee osteoarthritis. It has now been used to treat over 2,000 patients across Europe.

Rakesh Tailor, CEO of the Contura Group comments: “It has always been our aim to demonstrate the long term effectiveness and safety profile of Arthrosamid®. Our innovative hydrogel technology makes a meaningful and lasting different to patients’ lives and so we’re delighted to be able to present this data to clinicians at the OARSI World Congress. This data adds to the body of available evidence to position Arthrosamid® as a real game changer - a safe, effective and financially viable out-patient procedure with long lasting benefits for people whose day-to-day lives are detrimentally affected by knee osteoarthritis. We know from our consumer research that many people are looking for an alternative to the current standard treatment, namely invasive open knee surgery, which brings with it its own complications as well as important considerations of a hospital stay, lengthy recovery period and crucially, time off work. We hope that this 3 year data will make decision makers in the NHS and beyond see the value in increasing the accessibility of this minimally invasive treatment option which is now proven to have long lasting benefits for patients suffering from knee osteoarthritis.”

Mr Mark Webb, consultant orthopaedic surgeon at The London Orthopaedic Clinic, based in The King Edward VII’s Hospital Medical Centre, comments: “I’ve been treating patients with Arthrosamid® for over a year now and have consistently seen patients experiencing life changing reductions in pain as well as improvements in their mobility. Knee osteoarthritis is a debilitating condition for a significant patient population in the UK, and until now treatments have either been “short lived” or involve invasive knee replacement surgery. The new long term data for Arthrosamid® is a significant step forward for patients, giving them a valuable alternative that offers long-acting respite from the pain and immobility of knee osteoarthritis.”

To find out how you can deliver this treatment to patients in your clinic, contact the Contura Orthopaedics Team via for an appointment.

Centres offering Arthrosamid® can be found on the Get Treated Page here.



1. Henriksen, M., et al. (2023) 3 Year Results From a Prospective Study of Polyacrylamide Hydrogel for Knee Osteoarthritis. Poster 483 presented at OARSI 2023.

2. Bliddal H, Overgaard A, Hartkopp A, Beier J, Conaghan PG, et al. (2021) Polyacrylamide Hydrogel Injection for Knee Osteoarthritis: A 6 Months Prospective Study. J Orthop Res Ther 6: 1188.

3. Bliddal, H., et al. (2021). Polyacrylamide Hydrogel Injection for Knee Osteoarthritis: Results of a 52 Week Prospective Study. Osteoarthritis and Cartilage Vol.29 S278.

4. Bliddal, H., et al. (2022). A Prospective Study of Polyacrylamide Hydrogel Injection for Knee Osteoarthritis: Results From 2 Years After Treatment. Poster presented at OARSI 2022. Osteoarthritis and Cartilage Vol.30, Supplement 1, S371-S372. DOI:10.1016/ j.joca.2022.02.499.

5. Christensen, L., et al. (2016). Histological Appearance of the Synovial Membrane after Treatment of Knee Osteoarthritis with Polyacrylamide Gel Injections: A Case Report. Journal of Arthritis 5, 217.


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