Introduction

Medial-compartment knee osteoarthritis (OA) is a common and increasingly prevalent problem that affects the inner side of the knee. Over time, the cartilage that lines this area wears down, resulting in pain, stiffness, and a reduced ability to move comfortably. The medial compartment is crucial for supporting body weight and enabling movement , so damage here often leads to long-lasting symptoms that are hard to ignore.

Traditional treatments for inner knee OA—such as painkillers, physiotherapy , or even surgery—don’t always offer long-term relief. For people whose symptoms persist, a new injectable gel called Arthrosamid is showing promise. Designed to cushion and lubricate the joint, Arthrosamid aims to address the specific challenges of medial-compartment OA. In this article, we’ll look at the causes of inner knee OA, how Arthrosamid works, the latest clinical evidence, and what patients can expect from this innovative treatment.

Understanding Medial-Compartment Knee Osteoarthritis

The knee has three main compartments, with the medial compartment found on the inside of the joint. This part of the knee connects the inner parts of the thigh and shin bones—areas that take the brunt of our body weight when we move around.

When osteoarthritis develops in the medial compartment, the cartilage gradually thins and breaks down. This leads to increased friction, causing pain, inflammation, and stiffness—particularly along the inner side of the knee . Simple activities, like climbing stairs or standing up from a chair, can become challenging.

Knee instability often develops as part of this process. As the joint becomes less stable, muscles around the knee must work harder to offer support, sometimes leading to additional joint stress and discomfort.

While doctors usually start treatment for inner knee OA with NSAIDs and physiotherapy, these approaches have limitations. Painkillers may bring only short-lived relief and can have side effects if used long-term. Physiotherapy requires ongoing commitment, and surgery is invasive and requires significant recovery time . As a result, there’s a growing need for minimally invasive treatments that specifically target the inner knee and offer more lasting relief.

How Arthrosamid Works and Its Benefits

Arthrosamid is an injectable gel made from polyacrylamide hydrogel —a soft, water-rich material that closely resembles the fluid naturally found in healthy joints. When injected into the medial compartment of the knee, the gel integrates with existing joint fluid to create a cushioning layer inside the joint.

This cushioning does two main things: it absorbs shocks during movement and helps reduce friction between the bones. As a result, pain is eased, and the knee’s range of motion often improves. Arthrosamid helps restore some of the ‘spring’ and smoothness the joint loses when cartilage breaks down.

Unlike traditional hyaluronic acid injections , which the body gradually absorbs over a few months, Arthrosamid remains in the joint for much longer. This prolonged presence means that its supportive and pain-relieving effects can last, reducing the need for repeat treatments and offering sustained benefit over time.

Recent research supports the use of polyacrylamide hydrogel injections for knee osteoarthritis , showing notable improvements in symptoms for eligible patients, especially over a period of two years.

Clinical Evidence and Patient Outcomes

Studies have shown promising results for Arthrosamid in treating medial-compartment knee osteoarthritis . Using well-known tools like the WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) and the Visual Analog Scale (VAS) for pain, patients consistently report meaningful reductions in pain and improvements in knee function, often within weeks of treatment. For example, many see pain scores drop by 15 to 18 points on the WOMAC scale, indicating a significant improvement in daily life.

Long-term follow-ups show these benefits can continue for up to a year or more after just a single Arthrosamid injection . The safety record is reassuring as well: side effects such as mild pain or temporary swelling at the injection site are most common, while serious complications are rarely reported in multi-year studies.

Researchers have also identified factors that predict better outcomes with Arthrosamid . Older adults, those with lower-grade knee OA, and people with OA in both knees seem to benefit the most. Conversely, patients with more severe arthritis or certain health conditions, like diabetes, may have a lower chance of optimal improvement.

Importantly, the pain relief and functional improvements seen with Arthrosamid can help many patients stay active and avoid or delay surgery, all with a treatment that is minimally invasive and straightforward.

What to Expect from Arthrosamid Treatment

Arthrosamid is typically recommended for adults with moderate medial-compartment OA (often classified as Kellgren-Lawrence grade II or III on X-ray) who haven’t achieved sufficient relief with conservative treatments like physiotherapy and NSAIDs.

The procedure itself is quick and takes place in an outpatient clinic. After cleaning and numbing the knee, an ultrasound helps guide the injection into the correct compartment. About 6 millilitres of gel is injected, and the area is then dressed. Patients are observed briefly after the procedure before going home the same day.

There’s little downtime. Patients are advised to avoid intense physical activity for a few days, but normal activity can usually be resumed soon after. Often, physiotherapy is recommended following the injection to help strengthen the knee and enhance the benefits offered by the new cushioning.

Expert Support from Professor Paul Lee and MSK Doctors

Professor Paul Lee is an experienced orthopaedic specialist with a background in both surgery and rehabilitation. At MSK Doctors—a multi-specialist musculoskeletal clinic—Professor Lee leads a team dedicated to thorough assessment, patient safety, and personalised care.

MSK Doctors’ team-based approach ensures that Arthrosamid injections are delivered safely and in ways tailored to each patient’s needs. Along with careful diagnosis and treatment planning, the clinic offers individualised rehabilitation follow-up, helping patients improve and maintain knee function long after treatment.

Conclusion and Looking Ahead

Arthrosamid represents a promising new option for people struggling with medial-compartment knee osteoarthritis , especially when inner knee pain persists despite other treatments. By acting as a long-lasting cushion and lubricant inside the joint, Arthrosamid helps relieve pain, restore movement, and potentially delay the need for surgery.

Research is ongoing to determine just how long these benefits last and how best to combine Arthrosamid with other treatments like physiotherapy for optimal results. Further studies will refine our understanding of who benefits most and how the treatment fits into the wider spectrum of joint care.

As with any medical intervention, it’s essential to speak with a qualified healthcare professional to determine whether Arthrosamid is right for you.