Arthrosamid vs DUROLANE for knee osteoarthritis: which injection is right for you?

What are Arthrosamid and DUROLANE?

Arthrosamid

Arthrosamid is a 2.5% polyacrylamide hydrogel (often shortened to iPAAG). It is given as a single 6 mL injection into the knee joint and it is permanent: it is not designed to be broken down and absorbed by the body (Contura, 2025).

DUROLANE

DUROLANE is a stabilised hyaluronic acid gel. It is non-animal, made by bacterial fermentation, and comes as a single 3 mL injection at 20 mg/mL. Hyaluronic acid occurs naturally in joint fluid as a lubricant and shock absorber, and the injection aims to top it up (Bioventus, 2019). Unlike Arthrosamid, it is gradually absorbed, which is why it is sometimes repeated.

You can read more about each one in our Arthrosamid guide and DUROLANE guide.

Arthrosamid vs DUROLANE at a glance

What does the research say?

Arthrosamid

The main trial randomised 239 people with knee osteoarthritis to Arthrosamid or a single hyaluronic acid injection (Synvisc-One). At 26 weeks, WOMAC pain scores (out of 100) had improved by 18.5 points with Arthrosamid and 14.8 points with hyaluronic acid, and Arthrosamid was judged non-inferior, meaning not worse. Side effects related to the device were more common with Arthrosamid: 28.9% compared with 7.6%. All were mild or moderate (Bliddal et al., 2024).

Some people from that trial were followed for longer. At 3 years, those who stayed in the study had an average pain improvement of 13.1 points, with a clearer benefit in people under 70 (18.3 points) than in those aged 70 and over (3.9 points, which was not statistically significant) (Bliddal et al., 2026a). At 5 years, the 58 people who completed follow-up had an average improvement of 16.2 points (Bliddal et al., 2026b). These follow-ups had no comparison group after the first year and only around half of the original group completed 5 years, so they are encouraging but should be read with some caution.

DUROLANE

The key trial compared one DUROLANE injection with one steroid (methylprednisolone) injection in 442 people with painful osteoarthritis in one knee. At 12 weeks, the proportion who responded was similar, 44.6% with DUROLANE and 46.2% with the steroid, so DUROLANE was non-inferior. Between 12 and 26 weeks the benefit was maintained with DUROLANE while the steroid effect faded (Leighton et al., 2014).

It is fair to add that an earlier trial of 346 people found DUROLANE was no better than a saline injection overall at 26 weeks, although it did better in the subgroup whose osteoarthritis was only in the knee (Altman et al., 2004). A review of the evidence concluded it seems to work best in mild to moderate osteoarthritis in one knee, but that review was funded by the manufacturer (Leighton et al., 2018).

We are not aware of any trial comparing Arthrosamid and DUROLANE directly.

What does NICE say?

This matters, so we want to be straightforward about it. The NICE osteoarthritis guideline says: "Do not offer intra-articular hyaluronan injections to manage osteoarthritis" (NICE, 2022). DUROLANE is a hyaluronic acid (hyaluronan) injection, so it falls under that recommendation. Some clinicians disagree with this, and the injections are still used privately (Versus Arthritis, no date).

NICE has not published guidance recommending Arthrosamid. It was considered as a topic for evaluation and was not selected, reportedly because the evidence was judged insufficient at that stage (London Cartilage Clinic, no date). That is not the same as NICE saying it does not work.

NICE is clear about what comes first. It recommends therapeutic exercise tailored to the person for everyone with osteoarthritis, and weight loss for people who are overweight, noting that any amount helps and losing 10% of body weight is likely to be better than 5% (NICE, 2022). NICE also says a steroid injection can be considered when other medicines have not worked or are unsuitable, with relief usually lasting 2 to 10 weeks (NICE, 2022). Steroid injections are prescription only and are given after assessment by a qualified prescriber.

Which injection might suit you?

These are the questions we work through with patients.

• Have you given exercise and weight management a proper go? Injections work best alongside these, not instead of them.
• How do you feel about something permanent? Arthrosamid stays in the knee. DUROLANE is absorbed, so if you would rather start with something that wears off, it may suit you better.
• What is already in your knee? Arthrosamid is not given with a knee replacement or other foreign material in the knee, a previous non-absorbable implant, infection, keyhole surgery in the last 6 months, an unabsorbed hyaluronic acid injection, or uncontrolled haemophilia or anticoagulation. Its safety is not established in pregnancy, breastfeeding or with a BMI of 35 or more (Contura, 2025). DUROLANE should not be given with an infection in the knee or skin problems at the injection site, or if you are allergic to hyaluronic acid products (Bioventus, 2019).
• How much recovery time can you allow? After DUROLANE, the advice is to avoid strenuous activity or prolonged weight bearing for 48 hours (Bioventus, 2019). After Arthrosamid, strenuous activity is avoided for the first few weeks, and antibiotics are given beforehand to reduce infection risk (Contura, 2025).
• Your age. In the Arthrosamid 3-year follow-up, the benefit was clearer in people under 70 (Bliddal et al., 2026a), although this was a small subgroup.