Long‑lasting relief from knee osteoarthritis with Arthrosamid^®

Most patients begin to notice better mobility and reduced pain within two to four weeks of treatment, with continued gains typically reported between three and six months as the hydrogel integrates with the synovial lining over the first few months. Because Arthrosamid^® does not biodegrade, the relief tends to be more enduring than that seen with hyaluronic acid or PRP.

Five‑year follow‑up data from the IDA extension study, presented at WCO‑IOF‑ESCEO 2025 in Rome, demonstrate that single 6 ml injections of intra‑articular polyacrylamide hydrogel remain well tolerated and continue to produce statistically significant pain reduction at five years. The larger LUNA study is also tracking participants through to 2028.

The Arthrosamid^® product family has a safety profile developed over more than two decades. New 10‑year follow‑up data presented at WCO‑IOF‑ESCEO 2025 in Rome found no indications of unusual adverse reactions in surgical records from subsequent knee replacements, supporting the long‑term safety of the implant. Every injection at our clinic is performed under live ultrasound guidance using sterile, aseptic technique.

Although the risk of post‑injection joint infection is low (around 1 in 10,000), it is not zero. If you develop unexpected pain, warmth or redness around the joint, or a temperature, you should seek urgent medical attention via your GP or A&E and explain that you have recently had an intra‑articular injection.

According to the manufacturer's clinical trial data, the most common adverse events are injection‑related mild‑to‑moderate pain and/or mild swelling during the first weeks to months after the injection. Other recognised, generally minor risks include:

• Bruising around the injection point
• Tendon or nerve irritation
• Limited or absent symptomatic response
• Temporary worsening of joint symptoms

Arthrosamid^® is generally not suitable if any of the following apply:

• An active infection, especially at or near the injection site
• Haemophilia or current uncontrolled anticoagulant treatment
• A knee arthroscopy within the previous six months
• A recent intra‑articular hyaluronate injection (until it has fully worn off)
• A foreign body, prior knee replacement or other implant within the knee
• Pregnancy or breastfeeding, or under 18 years of age
• A known sensitivity to polyacrylamide
• An inflammatory arthritis such as rheumatoid or psoriatic arthritis
• Poorly controlled diabetes, an active autoimmune condition, or a major dental procedure planned in the near term

Before going ahead, the radiology consultant will discuss the balance of benefits and risks with you, review any contraindications, and ask you to sign an informed‑consent form before the injection is performed.

Arthrosamid^® can only be administered after a referral from a suitably qualified specialist. Because there is a small infection risk associated with any joint injection, prophylactic antibiotics are required between one and six hours before the procedure — your referring doctor will provide a prescription and clear timing instructions.

It also helps to wear loose clothing that allows easy access to the knee, and to plan your journey home in advance.

Once the local anaesthetic wears off, you may notice some discomfort around the joint — this is normal and usually short‑lived. Most clinicians now advise avoiding strenuous activity such as running, hiking, racquet sports or skiing for around two weeks while the joint settles. Gentle, day‑to‑day movement is encouraged from the outset.

Mild swelling or discomfort at the injection site can persist intermittently during the first weeks to months as the hydrogel integrates with the synovium. Because you may feel a little uncomfortable straight after the procedure, we strongly recommend bringing a friend or family member with you who can accompany you in clinic and drive you home afterwards.

Steroid injections work quickly but their benefits often fade after a few months. Hyaluronic acid (such as Ostenil^®) and platelet‑rich plasma (PRP) can deliver good symptom control, but both are gradually reabsorbed by the body and may need repeating. Arthrosamid^®, by contrast, is non‑biodegradable and integrates with the synovial lining over the first few months, which is why a single 6 ml injection has been shown to maintain meaningful pain reduction at five years rather than months. Your consultant will discuss which option fits your clinical picture, lifestyle and goals.