Pes Anserine Bursitis

Pes anserine bursitis is a common condition causing pain on the inner side of your knee, a few inches below the joint. It happens when a small, fluid-filled sac called the pes anserine bursa becomes inflamed. This bursa normally cushions three tendons from your shinbone, but overuse or other factors can lead to irritation and discomfort.

What is Pes Anserine Bursitis?

Pes anserine bursitis is an inflammation of the pes anserine bursa, a small, fluid-filled sac located on the inner side of your knee, about two to three inches below the joint. This bursa acts as a cushion, reducing friction between your shinbone and three specific tendons, often leading to pain and tenderness when irritated.

Your body has many small, fluid-filled sacs called bursae (plural of bursa). These bursae help to reduce friction between bones, tendons, and muscles as they move. The pes anserine bursa is found on the inner part of your lower knee. It sits between your shinbone (tibia) and a group of three tendons. These three tendons are from muscles in your thigh: the sartorius, gracilis, and semitendinosus. Together, they form a structure that resembles a goose's foot, which is why it's called "pes anserinus" (Latin for "goose's foot"). When this bursa becomes inflamed, it causes pain and tenderness in that specific area of your knee. This inflammation, or bursitis, can make everyday activities like walking, climbing stairs, or even sitting for long periods uncomfortable. It is a common cause of knee pain, especially in certain groups of people.

Symptoms

The main symptom of pes anserine bursitis is pain and tenderness on the inner side of your knee, typically two to three inches below the joint line. This discomfort often worsens with physical activity, such as climbing stairs or standing up, and may also be noticeable at night, sometimes disrupting sleep.

You will usually feel pain and tenderness directly over the pes anserine bursa. This spot is on the inside of your knee, a few inches below where your thigh bone meets your shin bone. The pain might be sharp or a dull ache. Activities that involve bending and straightening your knee can make the pain worse. This includes common movements like walking, running, going up or down stairs, or getting out of a chair. Some people also notice increased pain at night, especially if they sleep with their knees bent or pressed together. While pain and tenderness are the most common signs, you might also notice some mild swelling or warmth in the affected area. However, significant swelling or redness is less common with pes anserine bursitis and could suggest another issue.

Causes & risk factors

Pes anserine bursitis often develops from overuse or repetitive stress on the knee, particularly activities involving frequent bending and straightening. Several factors can increase your risk, including being overweight, having knee osteoarthritis, tight hamstring muscles, or certain structural issues like flat feet or "knock-knees."

The bursa can become inflamed from repeated friction or pressure. This often happens with activities that involve a lot of knee bending, such as running, cycling, or climbing stairs. Direct trauma to the inner knee can also trigger bursitis. Several factors can increase your likelihood of developing pes anserine bursitis. Being overweight or having obesity places extra stress on your knee joints and the surrounding structures, including the bursa. People with osteoarthritis (OA) of the knee are also more prone to this condition, as the joint changes can alter how the knee moves and increase friction. Other risk factors include tight hamstring muscles, which can pull on the tendons connected to the bursa. Certain foot and leg alignments, such as flat feet or "knock-knees" (valgus knee), can also change the mechanics of your knee and contribute to irritation. It is more commonly seen in middle-aged women, especially those who are overweight and have knee osteoarthritis.

How it's diagnosed

A doctor typically diagnoses pes anserine bursitis based on a physical examination and your reported symptoms. They will check for tenderness on the inner side of your knee and assess your range of motion. Imaging tests like X-rays are usually done to rule out other conditions, rather than to confirm bursitis itself.

When you see your doctor, they will ask about your symptoms, including when the pain started, what makes it worse, and what makes it better. They will then perform a physical exam of your knee. During this exam, your doctor will gently press on the inner side of your knee, specifically over the pes anserine bursa, to check for tenderness. They may also move your leg in different ways to see if certain movements cause pain or if your range of motion is limited. The diagnosis is often made based on these findings alone, as the location of the pain is quite specific to pes anserine bursitis. To rule out other potential causes of knee pain, such as a stress fracture, tendon injury, or knee osteoarthritis, your doctor might order imaging tests. An X-ray can show bone issues or signs of arthritis. In rare cases, if the diagnosis is unclear or if other conditions are suspected, a magnetic resonance imaging (MRI) scan might be used to get a more detailed view of the soft tissues.

Treatment options

Treatment for pes anserine bursitis usually begins with conservative methods aimed at reducing pain and inflammation. These often include rest, applying ice, taking anti-inflammatory medications, and engaging in physical therapy to stretch tight muscles and strengthen the knee. In some cases, a corticosteroid injection may be recommended to provide more targeted relief.

Most people find relief from pes anserine bursitis with simple, non-surgical treatments. The first steps often involve resting the affected knee and avoiding activities that worsen the pain. Applying ice packs to the inner knee for 15-20 minutes several times a day can help reduce inflammation and pain. Over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or naproxen, can also help manage pain and swelling. Your doctor might also recommend physical therapy. A physical therapist can teach you specific stretches for your hamstring muscles, which are often tight in people with this condition. They can also provide exercises to strengthen the muscles around your knee and hip, improving overall knee stability and mechanics. If conservative treatments are not enough, your doctor might suggest a corticosteroid injection. This involves injecting a powerful anti-inflammatory medication directly into the bursa. This can provide significant pain relief, though it is usually a temporary solution and not a cure. Surgery for pes anserine bursitis is very rare and typically only considered if all other treatments have failed.

Recovery & outlook

Most individuals with pes anserine bursitis experience a good recovery with conservative treatments, often seeing improvement within a few weeks to a few months. The outlook is generally positive, especially when risk factors like tight hamstrings or improper training are addressed through physical therapy and lifestyle adjustments.

The recovery period for pes anserine bursitis can vary, but many people start to feel better within a few weeks of beginning treatment. Full recovery often takes a few months, especially if you are actively participating in physical therapy and making necessary lifestyle changes. Consistency with your treatment plan is key to a successful outcome. The outlook for pes anserine bursitis is generally very positive. Most cases resolve completely with conservative management, and surgery is rarely needed. To help prevent the condition from returning, it's important to continue with exercises that stretch your hamstrings and strengthen your knee muscles. Addressing underlying risk factors, such as maintaining a healthy weight, using proper form during exercise, and wearing supportive footwear, can also significantly reduce the chance of recurrence. Your doctor or physical therapist can provide guidance on how to best manage these factors for long-term knee health.

When to see a doctor

You should see a doctor if your knee pain is severe, doesn't improve with rest and home care, or if it worsens over time. Seek medical attention if you notice new or increased swelling, redness, warmth, or if you develop a fever, as these could indicate a more serious infection or injury requiring prompt evaluation.

While many cases of pes anserine bursitis respond well to home care, it's important to know when to seek professional medical advice. If your pain is severe, prevents you from performing daily activities, or does not get better after a few days of rest and ice, you should contact your doctor. You should also see a doctor if you notice any new or worsening symptoms. This includes significant swelling, increased redness, or warmth around the knee, which could suggest an infection or another type of inflammation. If you develop a fever along with your knee pain, this is also a sign to seek immediate medical attention. Additionally, if you are unable to bear weight on your leg, or if the pain is accompanied by a "popping" sound or feeling at the time of injury, it's crucial to get evaluated by a healthcare professional. These symptoms could indicate a more serious injury that requires specific diagnosis and treatment.

Frequently asked questions

Can I continue exercising with pes anserine bursitis?

It's generally recommended to rest and avoid activities that worsen your knee pain when you first develop pes anserine bursitis. High-impact exercises or those involving repetitive knee bending should be paused. Once pain improves, you can gradually return to activity, focusing on low-impact options and exercises recommended by a physical therapist to strengthen muscles and improve flexibility.

How long does it take for a corticosteroid injection to work?

A corticosteroid injection for pes anserine bursitis can often provide pain relief within a few days to a week after the procedure. The duration of relief varies among individuals, but it can last for several weeks or even months. It's important to continue with other recommended treatments, like physical therapy, for long-term management.

Is pes anserine bursitis the same as "runner's knee"?

No, pes anserine bursitis is not the same as "runner's knee" (patellofemoral pain syndrome), although both can cause knee pain in runners. Runner's knee typically causes pain around or behind the kneecap. Pes anserine bursitis, however, specifically causes pain on the inner side of the knee, a few inches below the joint.

Can losing weight help with pes anserine bursitis?

Yes, losing excess weight can significantly help with pes anserine bursitis, especially if you are overweight or have obesity. Extra body weight places increased stress on your knee joints and the surrounding structures, including the bursa. Reducing this load can decrease friction and inflammation, aiding recovery and preventing recurrence.

What kind of stretches are good for pes anserine bursitis?

Stretches that target the hamstring muscles are particularly beneficial for pes anserine bursitis, as tight hamstrings are a common risk factor. Examples include gentle hamstring stretches, such as touching your toes or using a towel to pull your leg straight while lying down. A physical therapist can provide a personalized stretching and strengthening program.

Can I use heat for pes anserine bursitis?

Initially, ice is generally recommended for pes anserine bursitis to help reduce acute inflammation and pain. Once the initial inflammation has subsided, some people find that gentle heat can help relax tight muscles and improve blood flow. However, always consult your doctor or physical therapist for personalized advice on heat or ice application.

Sources

• MedlinePlus — Pes Anserine Bursitis
• Mayo Clinic — Pes Anserine Bursitis
• Cochrane Library — Pes Anserine Bursitis