Arthrosamid

Key Takeaways

• Arthrosamid is a polyacrylamide hydrogel injection for knee osteoarthritis
• Made by Contura International (Denmark), CE-marked in Europe since 2017
• Single injection may provide 2+ years of pain relief based on early data
• Not FDA-approved in the US and not covered by any insurance
• Promising but still considered an emerging treatment with limited evidence

If you have been researching knee injections lately, you have probably come across the name Arthrosamid. This relatively new treatment has generated significant interest because it works completely differently from traditional hyaluronic acid (HA) injections. Instead of temporarily lubricating the joint, Arthrosamid creates a permanent cushion inside the joint lining.

Here is what you need to know as a patient in 2026.

What Is Arthrosamid?

Arthrosamid is an intra-articular polyacrylamide hydrogel (iPAAG) developed by Contura International, a Danish medical device company. The product consists of:

• 2.5% cross-linked polyacrylamide (the structural component)
• 97.5% water (providing flexibility and cushioning)

This makes it a biocompatible hydrogel that the body does not break down or absorb. It has been CE-marked in Europe since 2017 and is used in clinics across Europe, the United Kingdom, and parts of Asia.

How It Works

Arthrosamid’s mechanism is fundamentally different from every hyaluronic acid product on the market.

Traditional HA injections add lubrication to the joint fluid. The body gradually absorbs the HA over weeks to months, which is why treatments must be repeated every 6 to 12 months.

Arthrosamid takes a different approach:

1. Injection: A single dose of the hydrogel is injected into the knee joint
2. Migration: The hydrogel migrates to the inner wall of the joint capsule
3. Integration: Over several weeks, it integrates into the synovial membrane (joint lining)
4. Cushioning: It restores thickness and elasticity to the joint lining
5. Permanence: The hydrogel remains in place because it is non-biodegradable

Think of it this way: HA injections are like adding oil to a squeaky hinge. Arthrosamid is more like replacing the worn padding around the hinge with a new, permanent cushion.

Who Makes Arthrosamid?

Contura International is headquartered in Denmark. The company specializes in polyacrylamide hydrogel products and has been developing iPAAG technology for various medical applications. Arthrosamid is their flagship orthopedic product.

Contura has been working toward FDA approval in the United States, but as of early 2026, the regulatory process is still underway. The timeline for a decision remains uncertain.

Clinical Evidence

What the Studies Show

Arthrosamid’s evidence base is growing but still limited compared to established treatments like hyaluronic acid injections, which have 25+ years of data.

MIVAC Trial (Published 2023)

• Randomized, double-blind, saline-controlled study
• Showed statistically significant pain reduction at 12 months
• Published in Osteoarthritis and Cartilage, a respected peer-reviewed journal
• Limitation: Relatively small sample size

24-Month Follow-Up Data

• Patients from the MIVAC trial continued to show sustained pain relief
• No repeat injections were needed during the follow-up period
• Improvement in WOMAC pain and function scores

Open-Label Extension Studies

• Some patients have reported continued benefit at 3+ years
• Safety profile remained favorable with low adverse event rates
• These are not blinded studies, so results must be interpreted cautiously

SYMPHONY Study

• Larger study designed to expand the evidence base
• Examining longer-term outcomes and safety
• Results will be important for strengthening Arthrosamid’s case

What We Still Do Not Know

• Long-term safety beyond 5 years has not been established
• No head-to-head trials comparing Arthrosamid directly to HA products
• Behavior of the permanent hydrogel over decades in the joint
• Impact on future surgical outcomes if knee replacement is eventually needed
• Which patient populations benefit most from this treatment

Who Is a Good Candidate?

Based on current evidence and clinical use in Europe, Arthrosamid may be appropriate for:

• Adults with mild to moderate knee osteoarthritis (Kellgren-Lawrence grades 2-3)
• Patients who have tried HA injections and found them insufficiently durable
• People who want to avoid repeat injection cycles every 6 months
• Patients with avian allergies who cannot use chicken-derived HA products like Synvisc
• Those willing to self-pay and potentially travel for treatment

Who Should Wait

Arthrosamid may not be the best choice for:

• Patients who want FDA-approved treatments with extensive safety records
• Anyone relying on Medicare or insurance to cover injection costs
• People with severe, bone-on-bone arthritis (limited data for advanced disease)
• Patients uncomfortable with a permanent, non-removable implant in their joint
• Those who cannot afford $3,000-$5,000 out of pocket

The Procedure

What to Expect

The Arthrosamid injection process is straightforward and similar to any knee injection:

1. Evaluation: Your doctor confirms you are a candidate based on imaging and symptoms
2. Preparation: The knee is cleaned and a local anesthetic numbs the area
3. Imaging guidance: Ultrasound or fluoroscopy is used to guide the needle
4. Injection: A single 6 mL dose of the hydrogel is injected into the joint
5. Observation: You are monitored briefly after the procedure

Procedure time: Approximately 15 to 20 minutes

Recovery

• First 24-48 hours: Avoid strenuous activity, apply ice as needed
• First week: Light walking is fine; avoid heavy exercise
• Weeks 2-4: Gradually return to normal activities
• Full benefit: Most patients notice improvement within 4 to 12 weeks as the hydrogel integrates

Unlike multi-injection HA series that require 3 to 5 weekly office visits, Arthrosamid is a single appointment.

Cost and Insurance

Current Cost

Since Arthrosamid is not FDA-approved in the US, costs are based on international clinic pricing:

• Typical range: $3,000 to $5,000 per injection
• Includes: Consultation, imaging, and the injection procedure
• Does not include: Travel, lodging, or follow-up care at home

Insurance Coverage

• Medicare: Not covered (no FDA approval, no HCPCS billing code)
• Private insurance: Not covered by any US insurer
• International clinics: Payment is typically required upfront

For comparison, a Synvisc-One injection with Medicare coverage costs most patients $50 to $150 out of pocket after coinsurance.

Cost Comparison

Even at the higher price, Arthrosamid could be cost-effective over several years if the duration claims hold up. A patient paying $800 per year for HA series would spend $2,400 over three years, compared to a single $3,000-$5,000 Arthrosamid injection.

Arthrosamid vs. Hyaluronic Acid: Key Differences

For a detailed comparison, see our Arthrosamid vs. Hyaluronic Acid guide.

FDA Approval Status

As of March 2026, Arthrosamid is not FDA-approved for use in the United States.

What This Means for US Patients

• You cannot receive Arthrosamid at any US clinic (outside clinical trials)
• No US pharmacy or distributor carries the product
• Insurance cannot cover a non-approved product
• Your US doctor cannot prescribe or administer it

The Path to FDA Approval

Contura International has been working toward FDA approval, which typically requires:

1. Pre-clinical data (completed)
2. Clinical trial results demonstrating safety and efficacy (ongoing)
3. FDA submission of a Pre-Market Approval (PMA) application
4. FDA review (can take 12-18 months after submission)
5. Advisory committee review (may or may not be required)

A realistic timeline for potential US availability could be 2027 to 2029, though this is speculative. FDA timelines are notoriously difficult to predict.

Potential Side Effects

Common (Similar to Other Knee Injections)

• Mild pain or discomfort at the injection site
• Temporary swelling of the knee
• Warmth around the joint for a few days
• Brief stiffness after the procedure

Less Common

• Joint effusion (excess fluid buildup)
• Infection (rare with proper sterile technique)

Unique Considerations

Because Arthrosamid is a permanent, non-biodegradable implant:

• It cannot be easily removed if complications develop
• Long-term effects of a permanent foreign material in the joint are not fully understood
• Imaging changes: The hydrogel may appear on future MRI or X-ray studies

There have been no reports of serious systemic reactions in published studies, but the patient population studied so far is relatively small.

Pros and Cons Summary

Pros

• Single injection instead of repeat series
• May last 2+ years based on current evidence
• Fully synthetic (no animal-derived ingredients)
• Does not appear to interfere with future surgery
• Growing body of clinical evidence

Cons

• Not FDA-approved in the US
• No insurance coverage anywhere in the US
• Limited long-term safety data
• Permanent implant cannot be removed easily
• Requires travel to international clinics (or clinical trial enrollment)
• Smaller evidence base than HA injections

Frequently Asked Questions

Is Arthrosamid available in the United States?

Not commercially. As of 2026, Arthrosamid is not FDA-approved and cannot be purchased or administered at US clinics. Some patients access it through clinical trials in the US or by traveling to clinics in Europe or the UK.

How long does Arthrosamid last?

Early clinical data suggests 2 to 3+ years of pain relief from a single injection. Some open-label studies report sustained benefit beyond 3 years. However, these are early findings that need confirmation in larger, longer-term studies.

Is Arthrosamid safe?

Published studies show a favorable safety profile with adverse events similar to other knee injections (temporary pain, swelling). The key unknown is very long-term safety, since the hydrogel is permanent and cannot be removed. No serious safety concerns have been identified in studies to date.

Can I get Arthrosamid if I have had HA injections before?

Yes. There is no known contraindication to receiving Arthrosamid after previous hyaluronic acid treatment. The two products work through completely different mechanisms.

Does Arthrosamid cure arthritis?

No. Arthrosamid does not regenerate cartilage or reverse osteoarthritis. It provides symptomatic relief by cushioning the joint lining. The underlying disease process continues, though patients may experience significantly less pain.

Will Arthrosamid affect a future knee replacement?

Based on available evidence, Arthrosamid does not interfere with knee replacement surgery. Surgeons in Europe have performed knee replacements on patients who previously received Arthrosamid without reported complications. However, long-term surgical outcome data is limited.

How is Arthrosamid different from Synvisc or other gel injections?

Synvisc and other HA products temporarily lubricate the joint and are absorbed by the body within months. Arthrosamid integrates into the joint lining permanently and does not break down. See our detailed comparison for more information.

The Bottom Line

Related Resources

• Arthrosamid vs. Synvisc Comparison
• Arthrosamid vs. Hyaluronic Acid
• Does Medicare Cover Arthrosamid?
• Hyaluronic Acid Injections: Complete Guide
• Knee Osteoarthritis Guide