Knee injections – Arthrosamid®

Arthrosamid® is a single, minimally invasive, long-lasting knee OA treatment.

A non-biodegradable injectable polyacrylamide hydrogel (2.5% iPAAG) implant for intra-articular use.

In a knee affected by OA, the synovium plays a central role in both acute and chronic disease.

Mechanical signalling (via mechanoreceptors) and chemical signalling (e.g. cytokines) drive OA progression and create a cycle of inflammation and damage.

Synovial inflammation, triggered by factors such as trauma or overuse, leads to a fibrotic and inelastic synovial membrane.

This, in turn, causes upregulation of mechanoreceptors in the synovium and in inflammatory cells, causing further inflammation and the clinical symptoms of OA — effusion, reduced function, and pain.

Delivered with a single injection

Arthrosamid® is injected into the synovial cavity, where it disperses within the synovial fluid. Its distribution follows the natural fluid flow of the joint, which is directed by knee movement.

Arthrosamid® is cleared from the synovial cavity and combines with the synovial membrane

Normal intimal transport mechanisms, which remove particulate material from the synovial cavity, also act on Arthrosamid®.

Through this process, the gel is transported through the synovial intima and into the synovial subintima.

Improved knee joint function

The physical presence of Arthrosamid® within the synovial tissue increases elasticity towards that of healthy tissue.

By removing stimuli for the mechanical pathway driving OA progression, this leads to improved joint function and long-lasting pain relief.

Complete integration

Once deposited in the synovial subintima, Arthrosamid® becomes integrated — a process largely complete within 4–6 weeks after injection.

The mature, stable local response to the implanted 2.5% iPAAG is characterised by a fine network of collagen fibrils enmeshed with Arthrosamid®, anchoring it as a permanent implant within the subintimal synovium.

This stable integration, 2.5% Polyacrylamide Hydrogel Synovial tissue which results in increased tissue elasticity, means that patients can experience long-lasting pain relief from knee OA