Introduction

Medial-compartment knee osteoarthritis (OA) is a common joint condition that mainly affects the inside part of the knee. It happens when the cartilage — the smooth, protective layer between bones — gradually wears away. This often leads to persistent pain, difficulties walking long distances, and discomfort when standing, all of which can affect everyday life. One major cause of this problem is a biomechanical issue called varus load, where the knee angles inward and puts extra pressure on the inner knee.

Arthrosamid is an exciting, minimally invasive treatment involving an injectable hydrogel that offers cushioning support specifically for the medial side of the knee. In this article, we explain what medial-compartment knee OA is, how Arthrosamid works to ease symptoms, and consider patient factors alongside the expert care available in London.

Understanding Medial-Compartment Knee Osteoarthritis

Medial-compartment knee OA is the most common type of knee osteoarthritis because the inner knee carries much of the body’s weight during movement and standing. Factors such as ageing, excess weight, previous knee injuries, and poor knee alignment can increase the risk. As the cartilage thins and disappears, bones begin to rub against one another, causing pain, swelling, and stiffness.

A key factor making things worse is varus alignment, where the leg bows outwards, increasing the load on the inner knee. This additional pressure speeds up cartilage damage and worsens symptoms when walking or standing. As a result, patients often find they cannot walk as far as before, and standing for long periods becomes uncomfortable or unsteady.

Treating this form of OA is particularly challenging because many traditional treatments do not target the exact mechanical stress or provide the cushioning needed. This can leave people struggling with pain and reduced mobility, affecting their quality of life.

Arthrosamid: A New Way to Cushion the Inner Knee

Arthrosamid is an injectable gel that acts like a soft cushion inside the knee joint, helping to reduce friction and shock where the cartilage has worn away. Unlike common treatments such as painkillers, steroid injections, or surgery, Arthrosamid is minimally invasive and offers relief without long recovery times.

By filling the joint space with a flexible, durable gel, Arthrosamid helps protect damaged cartilage and underlying bone from extra pressure. This support can slow down further wear, ease pain, and improve knee stability. Many patients notice they can walk further without discomfort and stand more comfortably after treatment.

Importantly, recent studies confirm that “Arthrosamid® has been known to be safe and efficacious in knee osteoarthritis (OA) patients” (Gao et al., 2025a). However, researchers also highlight that “the literature surrounding which patients would incur the most benefit from Arthrosamid is limited” (Gao et al., 2025a), pointing to the need for ongoing research and careful patient selection.

What Patients Can Expect and Individual Factors

Before receiving Arthrosamid, patients typically undergo a thorough assessment to confirm that their knee pain is due to medial-compartment OA and to rule out other causes. Those who are suitable often have persistent inner knee pain and want to avoid or delay surgery.

Research has emphasised the value of understanding which patients benefit most, noting “the need to identify which patient factors would allow Arthrosamid to provide the most clinical benefit in a knee OA patient” (Gao et al., 2025a). Factors such as age, severity of osteoarthritis, and general health influence treatment results.

While many people find that Arthrosamid reduces pain, increases walking distance, and improves standing comfort, individual results vary. The extent of benefit depends on how advanced the condition is, overall joint health, and lifestyle factors. That’s why a personalised approach by experienced healthcare professionals is essential.

It’s important to remember that Arthrosamid is not a cure but an innovative tool to manage symptoms and enhance quality of life as part of a wider treatment plan.

Expert Care: Professor Paul Lee and the London Cartilage Clinic

Professor Paul Lee is a leading expert in cartilage health and knee joint care. He holds several important roles, including Cartilage Expert and Regional Surgical Ambassador, and advises renowned surgical colleges. His expertise covers the latest advances in cartilage repair and preservation.

At the London Cartilage Clinic, patients benefit from a warm, expert-led environment using the most up-to-date techniques. The clinic offers comprehensive care, combining new treatments like injectable hydrogels with proven therapies to provide personalised management for knee problems.

Though neither the Professor nor the clinic developed Arthrosamid, their extensive experience ensures patients receive knowledgeable guidance and safe administration of such innovative treatments, helping them achieve the best possible outcomes.

Conclusion

Medial-compartment knee osteoarthritis poses unique challenges due to inner-knee cartilage wear and increased mechanical pressure. Arthrosamid provides a modern, minimally invasive approach to cushioning the joint, helping to reduce pain, improve walking distance, and increase comfort when standing. Consulting experienced specialists and trusted clinics is key to finding the right treatment for each individual.

For personal medical advice, please consult a qualified healthcare professional.

References

• Gao, H.C.K., Akhtar, M., Creedon, C., Nar, Ö.O., Verma, T., & Lee, P.Y.F. (2025). Polyacrylamide hydrogel injections in knee osteoarthritis: A PROMs-based 24 month cohort study. Journal of Clinical Orthopaedics and Trauma. https://doi.org/10.1016/j.jcot.2025.103136
• Gao, H.C.K., Akhtar, M., Creedon, C., Nar, Ö.O., & Lee, P.Y.F. (2025a). The impact of patient factors on the minimal clinically important difference of Arthrosamid polyacrylamide hydrogel injection for knee osteoarthritis: A cohort study. Osteoarthritis and Cartilage. https://doi.org/10.1016/j.joca.2025.02.648