The Old Guard vs. the New Challenger
A new type of knee injection has been generating buzz in the osteoarthritis world. Arthrosamid is a polyacrylamide hydrogel that works completely differently from traditional hyaluronic acid products like Synvisc. Instead of temporarily adding lubrication that breaks down over months, Arthrosamid integrates into the joint lining and may provide relief for years.
But is the hype warranted? Here is what we know as of 2026, and how Arthrosamid compares to the proven Synvisc option most patients already have access to.
Quick Comparison Table
| Feature | Arthrosamid | Synvisc |
|---|---|---|
| Type | Polyacrylamide hydrogel (iPAAG) | Cross-linked hyaluronic acid |
| How it works | Integrates into synovial membrane | Lubricates joint fluid |
| Injections needed | 1 | 3 weekly |
| Duration of relief | 2-3+ years (early data) | Up to 6 months |
| FDA approved (US) | No | Yes (since 1997) |
| CE marked (Europe) | Yes | Yes |
| Medicare covered | No | Yes |
| Self-pay cost | $3,000-$5,000 | $700-$1,000 |
| Available in US | Clinical trials only | Widely available |
| Source | Synthetic | Avian (chicken comb) |
| Allergy concerns | None (synthetic) | Egg/bird allergy risk |
| Years of safety data | ~10 years (EU) | 25+ years |
| HCPCS Code | None (not FDA-approved) | J7325 |
What Is Arthrosamid?
Arthrosamid is an intra-articular polyacrylamide hydrogel (iPAAG) made of 2.5% cross-linked polyacrylamide and 97.5% water. Developed by Contura International (Denmark), it was first CE-marked in Europe in 2017 for knee osteoarthritis.
How It Works (Different From Any HA Product)
Unlike hyaluronic acid, which temporarily supplements the joint fluid and is gradually broken down by the body, Arthrosamid takes a completely different approach:
- Injected as a single dose into the knee joint
- Integrates into the synovial membrane (the joint lining) within weeks
- Becomes a permanent, non-biodegradable cushion within the tissue
- Restores the elasticity and thickness of the joint lining
- Does not break down - the hydrogel remains in place indefinitely
This is fundamentally different from every HA product on the market. Synvisc, Monovisc, Euflexxa, and all other viscosupplements are broken down by the body within weeks to months, which is why they need to be repeated.
Arthrosamid Evidence (As of 2026)
- The MIVAC trial (published in Osteoarthritis and Cartilage, 2023) showed significant pain reduction at 12 months compared to saline
- 24-month follow-up data showed sustained benefit without repeat injections
- Open-label studies report continued improvement at 3+ years in some patients
- Safety profile appears favorable with low adverse event rates
- Limitations: Small trial sizes, no head-to-head comparisons with HA products, limited long-term data
What Is Synvisc?
Synvisc (hylan G-F 20) is a cross-linked hyaluronic acid derived from chicken combs, manufactured by Sanofi. It has been FDA-approved since 1997 and is one of the most widely studied and prescribed viscosupplements in the world.
How Synvisc Works
- Supplements depleted joint fluid with high-molecular-weight HA
- Provides temporary cushioning that reduces bone-on-bone contact
- Gradually absorbed by the body over weeks to months
- Must be repeated every 6 months for continued benefit
Synvisc Evidence
- 25+ years of FDA-approved use with extensive safety data
- Multiple large randomized controlled trials
- Real-world effectiveness confirmed across hundreds of thousands of patients
- Well-characterized side effect profile
- Consistent moderate evidence for pain relief lasting up to 6 months
Key Differences Explained
1. Duration of Relief
This is where Arthrosamid’s potential truly stands out.
Synvisc: Up to 6 months per treatment series. Most patients need retreatment twice per year.
Arthrosamid: Early data suggests 2-3+ years from a single injection. If confirmed in larger trials, this would be transformative. A patient who currently gets 2 Synvisc series per year could potentially get one Arthrosamid injection and be covered for years.
Caveat: Arthrosamid’s duration claims are based on smaller studies with shorter follow-up periods. We need larger, longer trials to confirm these numbers.
2. FDA Approval and US Availability
This is Arthrosamid’s biggest limitation for American patients.
- Synvisc: FDA-approved, widely available at orthopedic practices and pain clinics across the US
- Arthrosamid: Not FDA-approved. Available in Europe and the UK. Contura International has initiated the FDA approval process, but it may take several years. As of 2026, US patients can only access it through clinical trials.
3. Insurance Coverage
- Synvisc: Covered by Medicare Part B and most private insurance plans
- Arthrosamid: Not covered by any US insurance since it is not FDA-approved. Patients must pay $3,000-$5,000+ out of pocket at international clinics
4. Safety Profile
- Synvisc: Well-characterized after 25+ years. Known risks include injection site reactions, rare pseudoseptic reactions, and contraindication in patients with avian allergies
- Arthrosamid: Early safety data is encouraging, but long-term effects of a permanent non-biodegradable implant in the joint are not yet fully understood. If complications develop years later, the hydrogel cannot be easily removed
5. Allergy Considerations
- Synvisc: Derived from chicken combs. Contraindicated for patients with egg, poultry, or feather allergies
- Arthrosamid: Fully synthetic. No animal-derived components. Safe for patients with any allergies
Who Should Consider Synvisc?
- Patients who want a proven, FDA-approved treatment with decades of safety data
- Anyone who relies on Medicare or private insurance to cover treatment costs
- Patients who prefer a treatment that can be easily repeated or stopped
- Those who want widespread provider availability in the US
- Patients who are comfortable with 6-month treatment cycles
Who Might Consider Arthrosamid?
- Patients who have tried HA injections and want something longer-lasting
- Those who can self-pay $3,000-$5,000 and travel to an international clinic
- Patients with avian allergies who cannot use Synvisc or other chicken-derived products
- People who value single-injection convenience over a multi-injection series
- Those willing to accept the risk of a newer, less-studied treatment
Important Caution About Medical Tourism
Some patients travel abroad for Arthrosamid injections. If you consider this, verify the clinic’s credentials carefully, understand the risks of receiving treatment outside your home healthcare system, and inform your US doctor so they can monitor you appropriately.
Frequently Asked Questions
Is Arthrosamid available in the United States?
As of 2026, Arthrosamid is not FDA-approved and is not commercially available in the US. It is available in parts of Europe and the UK. Contura International is pursuing FDA approval, but the timeline is uncertain.
Is Arthrosamid better than Synvisc?
It is too early to say definitively. Arthrosamid shows promising early results with potentially longer duration, but it lacks the extensive safety and efficacy data that Synvisc has accumulated over 25+ years. Head-to-head comparative trials have not been completed.
Can I get Arthrosamid if Synvisc stopped working?
Potentially, but only outside the US or through clinical trials. There is no contraindication to trying Arthrosamid after HA injections, as the mechanisms are completely different.
Does Medicare cover Arthrosamid?
No. Because Arthrosamid is not FDA-approved in the US, it is not covered by Medicare, Medicaid, or any private insurance plan. The full cost must be paid out of pocket.
Is Arthrosamid permanent?
The polyacrylamide hydrogel is non-biodegradable, meaning it does not break down in the body. It integrates into the synovial membrane and remains there. This is both its advantage (potentially long-lasting relief) and a concern (difficult to remove if problems arise).
Can I still get knee replacement after Arthrosamid?
Based on available evidence, Arthrosamid does not interfere with future knee replacement surgery. However, long-term surgical outcome data in patients with prior Arthrosamid treatment is limited.
The Bottom Line
Proven vs. Promising
Synvisc remains the practical choice for most American patients in 2026. It is FDA-approved, Medicare-covered, widely available, and backed by 25+ years of safety data. It works well for the majority of knee OA patients.
Arthrosamid is a genuinely exciting innovation that may eventually change how we treat knee osteoarthritis. If larger trials confirm multi-year duration from a single injection, it could make repeated HA series obsolete. But until FDA approval, insurance coverage, and long-term safety data are established, it remains an experimental option.
Our recommendation: Stick with proven treatments like Synvisc unless you have a specific reason to pursue Arthrosamid abroad and can afford the out-of-pocket cost. Watch for FDA developments in the coming years.
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