Patellofemoral osteoarthritis is a common and often painful condition that affects the kneecap, making everyday activities like walking, climbing stairs, or even standing up from a chair difficult. This condition develops when the cartilage , which acts as a cushion between the bones in the kneecap joint, gradually wears away. As the protective layer thins, pain, swelling, and stiffness can take hold, impacting mobility and quality of life.

Arthrosamid is an innovative single-injection treatment that uses a hydrogel to relieve the symptoms of knee osteoarthritis . In this article, we’ll explain how Arthrosamid works, review recent clinical findings, and outline the patient care provided at the London Cartilage Clinic for those living with kneecap osteoarthritis .

Understanding Patellofemoral Osteoarthritis

The patellofemoral joint is where the kneecap ( patella ) rests and moves against the thigh bone (femur). Cartilage covers both surfaces, letting the bones glide smoothly with movement. When this cartilage breaks down in patellofemoral osteoarthritis , the bones can begin to rub together, causing pain, swelling, and stiffness.

Symptoms commonly include pain during activities—and even at rest in some cases—along with swelling, difficulty bending or straightening the knee , and occasional grinding sensations. The breakdown of cartilage can be triggered by several factors: changes in how weight is distributed across the joint, problems with the mechanics of the kneecap (like maltracking), or increased pressure in specific areas. Weak muscles or a slightly misaligned kneecap can also place extra stress on parts of the joint, accelerating cartilage wear and tear.

These mechanical factors play a key role in both the development and management of patellofemoral osteoarthritis , allowing healthcare professionals to target symptom relief more effectively.

However, it’s important to note that high-quality research guiding the optimal treatment of isolated patellofemoral osteoarthritis is still limited, highlighting the need for better studies in this area.

How Arthrosamid Works

Arthrosamid consists of 97.5% water and 2.5% cross-linked polyacrylamide —a polymer that forms a durable gel. Unlike many traditional injectable treatments that break down over time, Arthrosamid is designed to remain in the joint longer because it does not biodegrade.

Once injected into the knee, Arthrosamid hydrogel blends with the synovium (the lining of the joint) to create a cushioning effect. This helps thicken and restore the joint's natural lubrication, known as synovial fluid . In practical terms, Arthrosamid reduces friction in the joint, cushions surfaces during movement, and may help protect the remaining cartilage from further damage.

This process, called viscosupplementation, supports improved knee function and can provide relief from pain for a sustained period.

What Does the Evidence Say?

Clinical studies comparing Arthrosamid (also called intra-articular polyacrylamide gel , or iPAAG) and traditional hyaluronic acid injections have shown promising outcomes. Across follow-up periods up to 12 months, Arthrosamid matches or slightly exceeds the performance of hyaluronic acid in reducing pain and improving knee function—especially in patients under 70 and those with moderate cartilage damage.

Recent research has focused on which patients gain the most from Arthrosamid . A 24-month cohort study found that older patients, those with lower grades of osteoarthritis , people without diabetes , and individuals with both knees affected tended to experience the most benefit. Researchers used tools like the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Visual Analog Scale (VAS) to measure improvements in pain and stiffness. Many patients reported meaningful reduction in symptoms after Arthrosamid treatment , often reaching a state where their symptoms became manageable.

It’s worth emphasising that much of this evidence is still emerging. The same cohort study noted the need for controlled trials and a broader range of outcome measures to strengthen the conclusions drawn so far.

Other studies have observed that patellofemoral osteoarthritis is often found alongside other knee injuries , and treatments may include arthroscopy or physical therapy tailored to each patient’s situation. Non-surgical treatments—like physiotherapy , taping, and injection therapy —can provide short-term relief, but robust, long-term research is still needed to establish best practices for managing this condition.

Care and Treatment at London Cartilage Clinic

At the London Cartilage Clinic , patient care is delivered in a dedicated, professional environment. Professor Paul Lee, a leading expert in orthopaedics and rehabilitation, oversees the clinical programme with a focus on personalised care and safety.

Arthrosamid injections are performed as outpatient procedures under local anaesthetic, using ultrasound guidance for precise delivery into the joint. Following the injection, patients receive a structured rehabilitation plan designed to aid recovery, improve knee function, and extend the benefits of the treatment.

This comprehensive, evidence-based approach ensures patients receive expert attention and support throughout their recovery, with clear communication about expectations and outcomes.

Looking Ahead: Research and Treatment Considerations

While early studies are encouraging, further research is needed to clarify Arthrosamid ’s long-term safety and effectiveness, especially beyond the first year. Ongoing studies will also help determine how Arthrosamid compares to other injectable and surgical options, so clinicians can decide when it’s the most suitable choice.

Patient selection and personalised treatment plans remain essential, as individual factors can affect how well people respond to Arthrosamid . Close follow-up and ongoing assessment will continue to be important in achieving the best outcomes.

As the body of evidence grows, the role of Arthrosamid within a broader strategy for treating patellofemoral osteoarthritis will become increasingly defined.

In summary, Arthrosamid represents an exciting step forward for injectable treatments in kneecap osteoarthritis —offering prolonged symptom relief and improved joint function for many patients.

If you are considering Arthrosamid for patellofemoral osteoarthritis , the London Cartilage Clinic provides expert, patient-centred care led by Professor Paul Lee. For specific medical advice, always 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
Peña, V. W. H., & Vidal, J. (2020). Patellofemoral osteoarthritis: how do patients behave? Brazilian Journal of Implantology and Health Sciences, 2(12), 07-18. https://doi.org/10.36557/2674-8169.2020v2n12p07-18
van Jonbergen, H.-P. W., Poolman, R. W., & van Kampen, A. (2010). Isolated patellofemoral osteoarthritis. Acta Orthopaedica, 81(2), 199-205. https://doi.org/10.3109/17453671003628756