If you are considering arthrosamid injections, one of the biggest questions is how long the benefit may last. That matters because you are not just weighing up a single appointment. You are trying to understand whether the treatment may give meaningful relief for months, years, or something in between.

What “lasting” really means

When people ask how long arthrosamid injections last, they usually mean how long the pain relief and functional improvement last, not simply how long the material stays in the joint. Arthrosamid is a non-absorbable, non-biodegradable hydrogel used for symptomatic treatment of adult patients with knee osteoarthritis, and both Arthrosamid’s own materials and Regenesis describe it as a long-acting option given as a single injection.

That distinction matters. The hydrogel is designed to remain stable in the knee joint, but the more important question for patients is how long symptom relief is maintained in real life. Current clinical evidence and clinic guidance suggest that benefits from arthrosamid injections can last well beyond the first few months and, in some patients, continue for several years.

What the current evidence shows

The most practical short answer is that symptom relief from arthrosamid injections may last around 3 to 5 years in suitable patients, based on Regenesis’ current treatment page and longer-term published follow-up data. Regenesis states that Arthrosamid’s effect can last between three and five years, while its FAQ says a single injection can provide pain relief for up to three to five years, although some patients may need a repeat injection later depending on symptom progression.

The published research broadly supports the idea that Arthrosamid can be long-lasting, even if the exact duration varies by patient. A 2024 study reported a significant reduction in WOMAC pain at 52 weeks after a single injection, with similar improvements in stiffness, physical function, and patient global assessment.

Longer follow-up is where the treatment becomes especially interesting. A 2025 five-year extension study reported sustained and statistically significant improvements in WOMAC pain, stiffness, physical function, and patient global assessment after a single injection, suggesting that symptom relief can continue well beyond one or two years in at least some patients.

That does not mean every patient gets five years of strong relief. It means the available evidence shows that arthrosamid injections can be durable, with clinically meaningful benefit still present at five years in follow-up studies. That is a more realistic and accurate way to read the data than assuming the same timeline applies to everyone.

When you may notice the benefit

Another important point is that Arthrosamid is not usually an instant-result treatment. The Arthrosamid treatment process says some patients may feel pain relief within 24 hours, but maximum benefit can take up to 12 weeks. Regenesis similarly says most patients notice improvements in pain and joint function within four to six weeks, with fuller benefit often becoming clearer by around three months.

So, if you are judging how long arthrosamid injections last, it helps to think of the timeline in two parts. First, there is the early response period, when the knee may gradually begin to feel better over several weeks. Then there is the longer maintenance period, where the aim is sustained pain relief and better function over years rather than weeks alone.

Why the duration is different from person to person

No injection lasts the same amount of time for every patient. The severity of the osteoarthritis, the condition of the knee joint, age, activity level, and overall treatment plan can all affect how long the benefit feels meaningful. Regenesis notes that patients under 70 tend to experience the most substantial benefits, although older patients may still see worthwhile improvements.

It is also important to stay balanced about the evidence. NICE currently says Arthrosamid was not selected for Health Technology Evaluation guidance because the panel considered there to be insufficient evidence. That does not mean the treatment does not work, but it does mean the evidence base is still not as settled as many patients might assume from marketing language alone.

That is why a proper assessment matters more than any headline promise. Arthrosamid injections may last several years for the right patient, but they are still best viewed as one option within a broader osteoarthritis plan rather than a guaranteed long-term fix for every painful knee.

A realistic answer

The most honest answer is this: arthrosamid injections are designed as a long-acting treatment for knee osteoarthritis, and current evidence suggests that symptom relief may last from around one year to as long as three to five years in some patients. The strongest available follow-up data show meaningful improvements still present at five years, but the exact duration varies and cannot be guaranteed for everyone.

If you are exploring arthrosamid injections, the best next step is not to focus only on the maximum timeline. It is to find out whether you are a good candidate, how advanced your knee osteoarthritis is, and whether this treatment fits your symptoms and goals. Read more from Regenesis or get in touch to discuss whether Arthrosamid could be the right option for your knee pain.