Understanding Medial-compartment Knee Osteoarthritis: The Basics

Knee osteoarthritis (OA) is a common joint condition, especially as we get older. One frequent type affects the inner, or medial, part of the knee. This area tends to bear a lot of pressure during everyday movements and, over time, the cushioning cartilage gradually wears away. This causes pain, stiffness and often makes walking or standing for long periods uncomfortable. A key factor in this process is something called varus load, where the knee angles slightly inward, putting extra strain on the inner knee. Because of these challenges, treatments that specifically target the medial compartment are vital. New solutions like Arthrosamid injections are emerging, alongside physiotherapy, to offer a more personalised and effective approach to managing this condition.

What Happens in Medial-compartment Knee OA?

Medial-compartment knee OA occurs when the cartilage inside the inner knee joint breaks down. This area is particularly vulnerable because it carries more weight and stress during walking or standing, especially if the knee has a natural inward tilt. This extra strain speeds up cartilage loss and reduces the joint’s natural shock absorbers, leading to symptoms like pain and difficulty moving comfortably. People living with this condition often find their daily activities harder to manage due to discomfort and instability. Research shows that those with medial knee OA often experience a sense of their knee feeling ‘unstable’ or loose (Lewek et al., 2005). Addressing these symptoms requires treatment plans that focus not just on pain relief but also on improving joint stability and function.

Arthrosamid: A New Option for Inner-knee Support

Arthrosamid is a relatively new injectable treatment for medial-compartment knee OA. It consists of a gel designed to add cushioning inside the joint, helping reduce friction and protect the remaining cartilage. Studies looking at its effects over two years found that Arthrosamid improved symptoms, especially for older patients with less severe OA, and those without diabetes (Gao et al., 2025a). However, the research also points out that results can vary and more studies are needed to fully understand who benefits most. One important consideration is that Arthrosamid is not a cure but an additional option within a broader treatment plan. It aims to improve comfort during walking and standing, enhancing quality of life alongside other therapies.

Why Physiotherapy Still Matters

Even with new treatments like Arthrosamid, physiotherapy remains a cornerstone of managing medial-compartment knee OA. The right exercises strengthen muscles around the knee, help correct movement patterns, and improve joint stability. Interestingly, people with medial knee OA often adapt by tightening the muscles on the inner knee to try to keep it stable (Lewek et al., 2005). While this muscle co-contraction can help reduce feelings of instability, it may also increase pressure within the joint, potentially worsening cartilage damage over time. Physiotherapists work to balance these forces, guiding patients with exercises that promote safe movement and reduce strain. This integrated approach helps maintain mobility and reduces pain.

Expert Care for Personalised Treatment

Managing knee OA effectively requires tailored care from experienced specialists. Professor Paul Lee is a leading expert in cartilage health and knee osteoarthritis. Along with the MSK Doctors team, he offers advanced, evidence-based treatments in a patient-centred environment. By combining new therapies like Arthrosamid with tried-and-tested rehabilitation, this team creates personalised plans suited to each person’s needs, helping them feel confident about their recovery and mobility.

In Summary: A Holistic Approach to Medial-compartment Knee OA

Medial-compartment knee osteoarthritis presents specific challenges due to the pressure and strain on the inner knee. Arthrosamid offers an innovative way to boost joint cushioning and may help preserve cartilage, supporting greater comfort during daily activities. Yet, physiotherapy remains essential to address movement and stability issues and to protect the joint from further damage. Research highlights that older age, milder OA severity, and absence of diabetes are linked to better outcomes following Arthrosamid treatment (Gao et al., 2025a). Ultimately, expert care ensures that treatments are customised to each individual for the best possible results. If you’re managing knee OA, remember that advice from a qualified healthcare professional is key to finding the right approach for you.

References

• Gao, H. C. K., Akhtar, M., Creedon, C., Nar, Ö. O., & Lee, P. Y. (2025). 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, 33(Suppl 1), S361–S362. https://doi.org/10.1016/j.joca.2025.02.648
• 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, 41, 103136. https://doi.org/10.1016/j.jcot.2025.103136
• Lewek, M. D., Ramsey, D. K., Snyder-Mackler, L., & Rudolph, K. S. (2005). Knee stabilization in patients with medial compartment knee osteoarthritis. Arthritis & Rheumatism, 52(9), 2845–2853. https://doi.org/10.1002/art.21237