Introduction

Pes anserine bursitis and knee osteoarthritis frequently occur together, causing discomfort and limiting mobility for many people—especially older adults. Pes anserine bursitis refers to inflammation of a small fluid-filled sac (the bursa) on the inner side of the knee, where three tendons (the sartorius, gracilis, and semitendinosus) meet. Knee osteoarthritis, meanwhile, is a degenerative joint condition that causes the cartilage in the knee to wear down gradually, resulting in pain, stiffness, and reduced movement. Understanding how these two conditions are connected is key to providing effective care. In this article, we’ll explore why pes anserine bursitis often develops in people with knee osteoarthritis, and what can be done to manage the problem based on the latest research.

What Are Knee Osteoarthritis and Pes Anserine Bursitis?

Knee osteoarthritis is one of the leading causes of chronic knee pain, particularly in older adults. It typically causes joint stiffness, swelling, and difficulty moving the knee, making everyday activities like walking or climbing stairs more difficult. Pes anserine bursitis is less commonly talked about but can also be a significant source of pain on the inner side of the knee. The pes anserine bursa acts as a cushion between tendons and the shin bone, helping tendons move smoothly during activity. When this bursa becomes inflamed, it leads to pain, swelling, and tenderness that can easily be mistaken for osteoarthritis pain. Inflamed bursae can even mimic other internal knee issues, sometimes leading to unnecessary procedures if not diagnosed carefully. Changes in knee mechanics and weakening muscles due to osteoarthritis can both increase the risk of developing pes anserine bursitis. Studies highlight that pes anserine bursitis is fairly common in people with knee osteoarthritis and that it deserves attention as a cause of knee pain, especially when pain is localized to the inside of the knee. Occasionally, rare conditions can look just like bursitis, making a thorough diagnosis even more important.

How Biomechanics Play a Role

Biomechanics—the study of movement and the forces involved in it—helps explain why people with knee osteoarthritis are more likely to develop pes anserine bursitis. Osteoarthritis often leads to changes in how the knee aligns and moves. For example, if the knee tends to angle inwards (a condition called varus deformity), extra pressure is placed on the inside of the knee. This increased pressure can irritate the pes anserine bursa over time. Muscle imbalances are another contributing factor; weak thigh or hip muscles can change the way a person walks, putting further stress on the bursa. These mechanical issues, combined with repetitive strain from daily activities, are key triggers for bursitis. Imaging techniques like MRI and ultrasound can be extremely helpful, showing distinctive signs of pes anserine bursitis and ruling out other conditions. Factors such as age, gender, body weight, and the severity of osteoarthritis are also linked with a higher risk of developing this bursitis. Occasionally, other rare problems can present in a similar way, making imaging especially useful for a clear diagnosis.

Diagnosing and Managing Pes Anserine Bursitis in Knee Osteoarthritis

Diagnosis starts with a clinical examination, focusing on tenderness and pain over the inside of the knee, below the joint. If needed, ultrasound or MRI can confirm inflammation and rule out other causes. Imaging is particularly valuable in tricky cases or when symptoms don’t improve as expected. Most people respond well to simple treatments: rest, ice, and anti-inflammatory medications to reduce pain and swelling. Physiotherapy plays a crucial role by strengthening thigh and hip muscles, improving knee stability, and correcting faulty movement patterns. In cases where pain continues, doctors may offer a corticosteroid injection into the bursa to quickly reduce inflammation and discomfort. More recently, personalised rehab programs that include gait analysis and targeted muscle exercises have shown real promise. These approaches focus on relieving symptoms while also addressing the underlying movement problems that lead to bursitis in the first place.

Looking Ahead: The Future of Treatment

Pes anserine bursitis can be a challenging complication of knee osteoarthritis, but understanding how it develops opens up more targeted and effective treatments. By carefully diagnosing the problem and creating tailored therapy plans that strengthen key muscles and improve joint alignment, we can help people manage their pain and regain lost mobility. Ongoing research aims to make treatment even more personalized, considering each individual’s unique biomechanics and lifestyle. As science advances, we move closer to better outcomes and a higher quality of life for everyone dealing with these interconnected knee issues.