Pes Anserine Bursitis

Medical conditions are often given latin names such as pes anserine bursitis. However, for those that don’t speak latin, this condition refers to a portion of tissue known as the bursa in the knee that has become inflamed. This article will explore this condition by evaluating what it is, its causes, its symptoms, how it is diagnosed, and its treatment. We will also explore other aspects of the condition such as its complications and its prevention. 

What is pes anserine bursitis?

Pes anserine bursitis is an inflammatory condition which can cause chronic knee pain and weakness. The condition affects a bursa located within the knee which is below the pes anserinus. The tissues affected in this condition are niche and you’ve likely never heard of them before. Therefore, to understand this condition, we must outline these tissues in the knee.

Bursa is medieval Latin for “purse” and is the specific tissue in which the inflammation occurs. A bursa is a small fluid-filled sac that is located around bones and tendons (see image). The consistency of the fluid is similar to that of raw egg white. The function of this sac is to provide a cushion around a joint to reduce friction and allow free movement. Consequently, bursae are found in most major joints in the body, including the knee. In the condition of pes anserine bursitis, the bursa is located below the pes anserinus.

The pes anserinus is a structure of three tendons located above the bursa affected. It is commonly known as the “goose foot” due to its appearance as a webbed, foot-like structure.

The three tendons involved originate from the sartoriusgracilis and semitendinosus muscles. Again, these sound like complex medical terms but these are simply muscles in the thigh. While they have their own function and description, knowledge of this is not necessary in relation to pes anserine bursitis. However, it is necessary to know that the tendons of these muscles insert into (are attached to) the tibia. Therefore, when the underlying bursa becomes inflamed, these tendons are also affected in the knee.

Overall, the inflammation of the bursa, affecting the pes anserinus, is known as pes anserine bursitis. It causes pain, weakness and swelling in the knee. On assessment of patients with knee pain, 2.5% of individuals have the condition.1 There are also several causes for the condition.


The inflammation of the bursa in per anserine bursitis can be caused by a variety of factors. Bursitis can develop is from overuse or constant friction and stress on the bursa. For this reason, the condition is particularly common in athletes, especially runners who endure constant impact to their knees while running. In addition, people with osteoarthritis of the knee are also susceptible. 

Other factors that can contribute to to the development of inflammation and subsequently pes anserine bursitis include:

  • Harmful exercise techniques such as the absence of stretching, excessive hill sprint running and running at a pace above your body’s capability
  • Tight hamstring muscles
  • Obesity 
  • Out-toeing (feet that point outward than straight ahead) or knock-knees (knees that touch with ankles apart)
  • Diabetes2

Clinical presentation

When visiting the doctor, there will be several signs that point to pes anserine bursitis. A doctor will perform a physical examination which will assess the clinical presentation of the condition.1 Signs include:

  • Pain
  • Localised tenderness
  • Warmth
  • Edema
  • Erythema of the skin

Difference between pes anserine bursitis and other knee pain

Knee pain is a very common symptom in some injuries. One cause is bursitis and it is caused by inflammation. Similar knee pains can be caused by inflammation as well. Causes include tendonitis and Osgood-schlatter’s disease. However, the inflammation in these conditions is in different areas. Tendonitis is an inflammation of the tendons of the muscles and is often localised between the shin and the kneecap. Osgood-Schlatter’s disease is an inflammation of the area just below the knee and is often present in adolescents. In addition, pain can be caused by more physical injuries including a torn ligament, tendon or meniscus; cartilage damage; sprains and a dislocated kneecap. The damage in these injuries leads to the pain and is a distinct cause from pes anserine bursitis.


While we have already mentioned some signs on clinical presentation of per anserine bursitis, there are other symptoms as well. The most common symptom of the condition is knee pain which gets better with rest but significantly worsens with exercise. Knee pain is generally an uncomfortable feeling so should be addressed immediately. Another symptom that will accompany the pain is a puffy tenderness in the affected knee.


In order for correct treatment to take place, a diagnosis should be performed. After symptoms have been presented, a doctor can perform several tests to assess that per anserine bursitis is the actual cause of the knee pain. Two of the tests that can be performed are ultrasounds or MRIs.


Ultrasound is a method by which to image the body and is well-kmown for being used to view babies in the mother’s womb. It is a method that uses high-frequency sound waves directed at the body. We cannot hear these sound waves but they will reflect off our body parts which can then be picked up by a sensor. These are then translated into an image of the body part. The pes anserine bursa is one body part that can be imaged by an ultrasound.3 It can be as effective as an MRI at this. As well as being able to image the bursa itself, it can also show the degree of inflammation that occurs in the bursa. 


An MRI is another imaging technique that can be used to assess the structure of a body part. This technique makes use of a very powerful magnetic field which interacts with hydrogen atoms in the body. In addition, it is highly detailed so can show the structure of the bursa. In the case of pes anserine bursitis, it can show an increase in the amount of fluid in the bursa so showing inflammation.4


As the knee pain that can be produced in this condition is uncomfortable, efforts are made to treat the condition to either remove the pain or cure the condition. Treatment options can include medication, rest, physical therapy, PRP injections, surgery and ice.


Painkillers may be prescribed to quell the pain or inflammation in the condition. A common group of painkillers are the NSAIDs (non-steroidal anti-inflammatory drugs) which include ibuprofen. More powerful painkillers can also be prescribed.


As the condition can be exacerbated by exercise, it is advisable to rest the affected leg and let the healing process begin.

Physical therapy

While rest is appreciated, physical therapy may be needed to aid the recovery process. This can be a variety of treatment options such as stretching the affected knee. The objective of this is to reduce tension from the muscles on the affected area. This can help ease the pain to the knee and potentially inflammation as well.

PRP injections

PRP stands for platelet-rich plasma. Platelets are involved in the healing process. For example, if you get a cut to your skin, platelets will form the scab to prevent further bleeding. In relation to the knee and pes anserine bursitis, the injections will help speed up the healing process.


This treatment option will ideally only be used in extreme and rare cases as it could potentially do more damage than good. However, if surgery does take place, the bursa will be removed to eliminate the pain and inflammation. Patients who undergo surgery for this condition will return to normal activities in 3 to 4 weeks.


Ice is another form of physical therapy that can be applied as treatment. The ice is commonly used in conditions which affect the muscles or tendons. It is effective as it reduces circulation to the affected area and so reduces inflammation.


While it is rare to develop complications from pes anserine bursitis, it can happen. Complications are more likely to arise if the condition goes untreated and causes more damage. These include further increased inflammation or weakened muscles.


One of the main ways to prevent development of pes anserine bursitis is to stretch the muscles in the legs. Certain stretches can be recommended by the doctor but generally hamstring stretches can help. This is because the pes anserine tendons are attached to muscles in the hamstrings. 

Another prevention technique is to lose weight. As obesity is one possible cause of the condition, losing weight if you are obese or over-weight can help limit the risk that pes anserine bursitis will develop.

When to see a doctor

Generally you should see a doctor if the pain in your knee becomes uncomfortable and constant. Even if the pain ends up being nothing to worry about, it is still worthwhile to see a doctor about knee pain.


Pes anserine bursitis is a condition that affects the knee. It originates from a bursa that underlies the pes anserine (or goose’s foot) which connects several hamstring muscles into the tibia. Overall, the condition is an inflammation of the bursa here. It causes pain and weakness in the knee. Once the clinical signs have appeared, diagnosis can take place which can utilise ultrasounds or MRIs. After diagnosis, a treatment regime can begin which includes physical therapy and at the extreme end surgery. However, the condition can be prevented with stretching/physical therapy and losing weight if you are obese or overweight.


  1. Rennie WJ, Saifuddin A. Pes anserine bursitis: incidence in symptomatic knees and clinical presentation. Skeletal Radiol [Internet]. 2005 [cited 2023 Mar 9]; 34(7):395–8. Available from:
  2. Helfenstein Jr M, Kuromoto J. A síndrome anserina. Rev Bras Reumatol [Internet]. 2010 [cited 2023 Mar 9]; 50:313–27. Available from:
  3. Imani F, Rahimzadeh P, Abolhasan Gharehdag F, Faiz SHR. Sonoanatomic Variation of Pes Anserine Bursa. Korean J Pain [Internet]. 2013 [cited 2023 Mar 9]; 26(3):249–54. Available from:
  4. Forbes JR, Helms CA, Janzen DL. Acute pes anserine bursitis: MR imaging. Radiology [Internet]. 1995 [cited 2023 Mar 9]; 194(2):525–7. Available from:
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Miles Peter Bremridge

Masters of Science - MSc Neuroscience Student and Neurosoc Chair, The University of Manchester, England

Miles Bremridge is a MSc Neuroscience Student who is working as a Neurosoc UoM Social Secretary at The University of Manchester. He is also an experienced Medical Writer.

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