Introduction

Medial-compartment osteoarthritis (OA), often called inner knee osteoarthritis, is a common and often painful condition affecting many adults, especially those who lead an active lifestyle. It occurs when the cartilage on the inside of the knee gradually wears away, causing pain, stiffness, and making movement more difficult. Everyday activities like walking long distances or standing for a long time can become challenging. This condition is frequently linked to increased inward pressure (called varus loading) on the knee, which speeds up cartilage damage. Recently, a new injectable treatment called Arthrosamid has been developed to help improve cushioning inside the knee joint. In this article, we’ll explore what medial-compartment knee OA is, how Arthrosamid works as a targeted treatment, the clinical context around its use, and the vital role expert-led clinics play in delivering the best care.

Understanding Medial-compartment Knee OA

Medial-compartment knee OA most often affects middle-aged and older adults, but younger people can also develop it, particularly after knee injuries. The main symptoms include persistent inner knee pain, swelling, stiffness, and a noticeable drop in how far you can walk without discomfort. A varus deformity, where the lower leg angles inward compared to the thigh, causes extra stress on the inner knee cartilage. This uneven pressure disrupts normal knee movement, leading to quicker cartilage breakdown and worsening pain and disability. Healthy cartilage is essential as it cushions the joint and soaks up shocks when we move. When this cushioning is lost, bones can rub directly against each other, causing pain and limited mobility. Traditional treatments include pain relief medication, physiotherapy, or surgery such as realignment or knee replacement. Bone cement is sometimes used in orthopaedic surgery to stabilise fractures or support implants, highlighting how important it is to properly support joint structures. Yet, there remains a strong need for less invasive options that preserve joint function, especially in the earlier stages of OA.

Arthrosamid: A Targeted Solution for Inner Knee OA

Arthrosamid is a specially designed injectable gel that targets the cushioning loss inside the medial knee compartment. It works by thickening and increasing the volume of the synovial fluid—the joint’s natural lubricant—helping to absorb shocks and reduce pressure on the cartilage. This added cushioning can protect the joint from further damage and ease the pain caused by worn cartilage. Arthrosamid is best suited for people with early to moderate medial-compartment OA who want to avoid or delay surgery. Recent research confirms that “PAAG provided improvement in knee OA symptoms over 24 months, in older, non-diabetic patients with lower KL grades over 24 months.” Many patients experience better walking distance and greater comfort when standing, thanks to the restored cushioning effect inside the knee. Pain relief and improved quality of life have also been reported. Because Arthrosamid is minimally invasive, it offers an excellent alternative or addition to traditional conservative treatments.

The Clinical Setting: Bone Cement, Position Statements, and Patient Impact

Bone cement plays an important role in orthopaedics, particularly when treating trauma cases, neck of femur fractures, or supporting complex implants in cancer patients. British orthopaedic societies have issued guidelines emphasising the safe and effective use of bone cement in these situations. However, clinics specialising in joint preservation and osteoarthritis treatment often prefer uncemented implants, which have shown excellent results with fewer complications linked to cement. This approach aligns well with treatments like Arthrosamid, which are innovative yet mindful of patient safety and national best practices. It’s important to note that when interpreting treatment results, “the absence of a control group and limited outcome measures should be considered.” By choosing the right patients and appropriate therapies, clinicians can avoid unnecessary risks and focus on maintaining joint health and mobility. This balanced approach combines innovation with caution and care.

The Role of Leadership in Joint Care: Professor Paul Lee and MSK Doctors

Skilled leadership is essential in musculoskeletal care to ensure patients receive the best and most up-to-date treatments. Professor Paul Lee, an internationally recognised expert in cartilage health, serves as a Regional Surgical Ambassador and Advisor to the Royal College of Surgeons of Edinburgh. His wide-ranging clinical experience and commitment to ongoing education provide a firm foundation for exceptional joint care. The team of MSK Doctors, led by Professor Lee, creates a supportive, patient-focused environment that encourages informed choices and smooth recovery. By championing evidence-based and comprehensive treatment plans, they ensure patients can access modern therapies such as Arthrosamid. This expert-led approach gives patients confidence that their care is both highly professional and personalised to their needs.

Conclusion

Medial-compartment knee osteoarthritis is a challenging condition that impacts mobility and quality of life, largely because of the crucial cushioning role played by inner knee cartilage. Treatments like Arthrosamid offer a promising, minimally invasive way to restore that important cushioning and help decrease symptoms in the early to moderate stages of OA. When combined with expert clinical care from teams like Professor Paul Lee and MSK Doctors, patients can navigate their osteoarthritis journey with reassurance and hope. Research reminds us that “further studies are warranted to validate efficacy, refine patient selection, and evaluate long-term impact.” For anyone affected by medial-compartment OA, consulting a specialist orthopaedic team is key to accessing novel, evidence-based treatments. Taking this step could lead to better knee function, less pain, and an improved quality of life.

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, (advance online publication). 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, (advance online publication). https://doi.org/10.1016/j.jcot.2025.103136