Arthrosamid for Knee Osteoarthritis: What It Is, Who It May Suit, and What to Expect
Notes on procedural naturopathic medicine.
Knee osteoarthritis pain can persist even when physiotherapy, activity changes, and first-line care are already in place. If you are considering an injection as a next step, Arthrosamid is one ultrasound-guided option I offer in clinic for patients with knee OA — alongside cortisone, hyaluronic acid, and PRP when those are a good fit.
In my practice, Arthrosamid is placed with ultrasound using a Mindray MX7 at Tall Tree Cordova Bay. That guidance helps us put the hydrogel where it is meant to go. Like every joint injection, results vary from person to person — and no injection reverses osteoarthritis. For the right patient, though, Arthrosamid can be a thoughtful, longer-horizon option when shorter-acting injections have not been enough.
What Arthrosamid is
Arthrosamid is a soft hydrogel designed to be injected into the knee joint. Manufacturer materials describe roughly 2.5% cross-linked polyacrylamide and 97.5% non-pyrogenic water, usually given as a single knee injection — often discussed as 6 mL (six 1 mL syringes).
Arthrosamid is Health Canada approved as of 2024 as a Class 3 medical device for symptomatic knee osteoarthritis in adults who have not had enough relief from conservative care.
Manufacturer materials describe the hydrogel integrating into the lining of the joint and forming a cushion-like layer. That is a way of supporting the joint environment — not a claim that cartilage is rebuilt or that osteoarthritis is cured.
Who it may be for — and who it may not
It may be a good conversation when:
- You have diagnosed knee osteoarthritis (based on your history, exam, and often imaging)
- First-line care and prior injections have not given enough lasting relief
A consult decides whether it is right for you. Screening themes from manufacturer instructions for use (general education only — not your personal clearance) include situations such as:
- Active skin disease or infection at or near the injection site
- An infected or severely inflamed joint
- A prior non-absorbable injectable or implant in the same knee
- A recent absorbable injectable (for example hyaluronic acid) that is not yet expected to be absorbed per that product’s labelling
- Knee replacement hardware or other foreign material in the knee
- Knee arthroscopy within the last 6 months
- Uncontrolled haemophilia or uncontrolled anticoagulation
Other factors — other joint disease, recent surgery, infection elsewhere, immune status, diabetes control, BMI, pregnancy or lactation — also shape whether an injection is appropriate. That conversation belongs in clinic, with your own history in front of us.
I provide clinical care for these procedures in British Columbia only, through booked consults at Tall Tree Cordova Bay.
Why ultrasound guidance
Ultrasound helps us see the joint space so the needle can be placed carefully, rather than estimating from surface landmarks alone. It is about accuracy and confidence in placement — not a guarantee of how you will feel afterward.
Reviews of randomized trials have found ultrasound-guided knee injections more accurate than landmark (“blind”) injections. Separate research in osteoarthritis has also reported better short-term pain and function scores with ultrasound guidance versus landmark guidance in the pooled knee studies available. That is why I use the Mindray MX7 for Arthrosamid and other knee injectables in my practice.
What a visit looks like
A typical path in my practice:
- Initial Assessment — history, exam, prior treatments, and relevant imaging. Suitability for Arthrosamid (or another injectable) is decided here. If Arthrosamid is appropriate, prophylactic antibiotics are required before the injection; the dose is prescribed at this visit based on suitability.
- Follow-up Injection Visit includes skin prep under aseptic technique, local anesthetic at the injection site, ultrasound-guided injection using the Mindray MX7, and a review of post-care and aftercare information. Manufacturer dosing for a treated knee is commonly framed as one 6 mL injection.
Manufacturer materials advise avoiding strenuous activity (for example tennis, jogging, or long walks) during the first weeks after injection. Mild soreness or swelling in the early weeks is among the common effects described in those materials.
How it differs from cortisone, hyaluronic acid, and PRP
Think of these as different tools for different needs, not a ranked list. For the fuller options map, see my earlier post: Ultrasound-Guided Knee Injections for Osteoarthritis: Cortisone, HA, PRP, and Arthrosamid.
| Cortisone | Hyaluronic acid | PRP | Arthrosamid | |
|---|---|---|---|---|
| What it is | Anti-inflammatory medicine | Joint “gel” viscosupplement (brands I use: Cingal, Durolane) | A concentrate made from your own platelets | A hydrogel (polyacrylamide + water) that can integrate with the joint lining |
| Typical frame | Shorter-term relief | Medium-term support | Biologic; depends on how it is prepared | Often a single injection, with longer follow-up discussed in published studies |
| Repeats | Often time-limited courses | Depends on the product | Depends on the protocol | Manufacturer notes that repeat dosing has not been studied the same way as the single-dose work |
What the evidence does — and does not — say
Published findings are group averages. Individual results vary. Nothing here is a cure, a guaranteed number of years of relief, or proof that Arthrosamid is “better than” every other option for every patient.
Compared with hyaluronic acid. In a randomized trial of 239 participants, Bliddal and colleagues compared a single 6 mL polyacrylamide hydrogel injection with hyaluronic acid. At 26 weeks, the hydrogel met the study’s non-inferiority criterion on WOMAC pain versus HA — meaning it performed at least as well as hyaluronic acid on that pain measure. Benefits and a comparable safety profile were still reported at 52 weeks. That is encouraging, and it is not the same as proven superiority.
One-year open-label follow-up. In a multicentre open-label study of a single 6 mL injection, patients showed sustained improvement through 52 weeks, including a meaningful drop in WOMAC pain (about 18 points on a 0–100 scale from baseline) and roughly 62% meeting OMERACT-OARSI responder criteria at one year. Open-label studies do not have a placebo comparison group, so they sit alongside — not instead of — the randomized data.
Longer follow-up after one injection. In the five-year extension of that work, participants who remained in follow-up continued to show improvements from baseline in pain, stiffness, function, and how they rated their knee overall (for example, WOMAC pain about −15 points at five years in the mixed-model analysis). Dropout and study-design limits matter when you read those papers — smaller numbers complete long follow-up — but the signal is sustained benefit after a single injection for many who stayed in the study.
What we do not yet have is a large published head-to-head trial proving Arthrosamid is superior to cortisone or PRP. The honest read today: solid non-inferiority versus hyaluronic acid, plus open-label data suggesting durable improvement for a meaningful share of patients — always weighed against your knee, imaging, and goals in clinic.
FAQs
What is Arthrosamid made of?
Manufacturer materials describe about 2.5% cross-linked polyacrylamide and 97.5% water — a soft hydrogel intended for injection into the knee joint in osteoarthritis.
Is it the same as a steroid or a gel shot?
No. Cortisone is an anti-inflammatory medicine. Hyaluronic acid products (in my practice for joints: Cingal or Durolane) are viscosupplements. Arthrosamid is a polyacrylamide hydrogel with a different makeup and a different evidence map. Whether it is right for you is still a consult decision.
Does Arthrosamid reverse osteoarthritis?
No. No injection reverses osteoarthritis. The conversation is about comfort, function, and choosing a tool that fits your knee and your goals.
Can I book if I am outside British Columbia?
I provide clinical care for these procedures in British Columbia only. Assessment and injection happen in person at Tall Tree Cordova Bay for BC patients.
How do I book?
Start with a consult through the ultrasound-guided injection pathway at Cordova Bay, or read the service overview first and then book.
If knee osteoarthritis is getting in the way of what you want to do and you are in British Columbia, you are welcome to book a consult. We can sit down together and map whether ultrasound-guided Arthrosamid — or another injectable — is a good fit for your knee.
- Service overview: Ultrasound-guided injections
- Options map (cortisone / HA / PRP / Arthrosamid): Ultrasound-guided knee OA injectables
- Book: US-guided injection — Tall Tree Cordova Bay
A precision practice · naturalwellnesswithsyd.com · @dr.sydgreen
Sources
- Fang WH, Chen XT, Vangsness CT Jr. Ultrasound-guided knee injections are more accurate than blind injections: a systematic review of randomized controlled trials. Arthrosc Sports Med Rehabil. 2021;3(4):e1177–e1187. https://doi.org/10.1016/j.asmr.2021.01.028
- Oo WM, et al. Comparison of ultrasound guidance with landmark guidance for symptomatic benefits in knee, hip and hand osteoarthritis: systematic review and meta-analysis of randomised controlled trials. Australas J Ultrasound Med. 2024. https://pmc.ncbi.nlm.nih.gov/articles/PMC11109994/
- Bliddal H, Beier J, Hartkopp A, Conaghan PG, Henriksen M. Polyacrylamide gel versus hyaluronic acid for the treatment of knee osteoarthritis: a randomised controlled study. Clin Exp Rheumatol. 2024;42(9):1729–1735. https://doi.org/10.55563/clinexprheumatol/i3fqee
- Henriksen M, 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 / related open-label series. https://pmc.ncbi.nlm.nih.gov/articles/PMC11064315/
- Bliddal H, Hartkopp A, Beier J, Conaghan PG, Henriksen M. A prospective, open-label, clinical investigation of a single intra-articular polyacrylamide hydrogel injection in participants with knee osteoarthritis: a 5-year extension study. J Orthop Surg Res. https://pmc.ncbi.nlm.nih.gov/articles/PMC12817702/
- Contura International A/S. Arthrosamid — Summary of Safety and Clinical Performance (SSCP). https://contura.com/wp-content/uploads/2025/11/018.SSCP_.00023.03-v001-Arthrosamid_final_for-upload-to-webpage.pdf
- Contura International A/S. Arthrosamid — Instructions for Use. https://contura.com/wp-content/uploads/2025/11/05_8252680_NY_Arthrosamid-10117-001-_72x215_okt2025_forside.pdf
- Contura Orthopedics. Contura Orthopedics expands to Canada, bringing Arthrosamid to North America (Health Canada authorization, 2024). https://arthrosamid.com/en-CA/post/contura-orthopedics-expands-to-canada-bringing-arthrosamid-to-north-america
Disclaimer
This content is general educational information, not medical advice, and not a substitute for individualized care from your own qualified provider. Dr. Sydney Green, ND provides clinical care only to patients within British Columbia.