Pes Anserine Bursitis

What is Pes Anserine Bursitis?

“Pes anserinus” is a Latin term that means “goose’s foot”. It refers to the point where three tendons join, specifically the sartorius, gracilis, and semitendinosus, on the inner, upper part of your shinbone (tibia). Each of these tendons is controlled by a separate nerve and together they form a structure about 2 inches below the knee joint on the inside of the leg. These muscles play an important role in bending the knee, rotating the shinbone inwards, and protecting the knee from certain types of stress.

Just underneath these tendons is something called the pes anserinus bursa. This is a small, fluid-filled sac that makes it easier for the tendons to move smoothly across the shinbone. Sometimes, this sac also provides a cushion between the tendons and the ligament on the inside of your knee (the medial collateral ligament, or MCL). If the bursa gets injured, it can become inflamed and produce more fluid, leading to pain.

Close to the pes anserinus bursa is another sac, called the musculi sartorii bursa. This is located between the sartorius tendon and the combined gracilis and semitendinosus tendons. It’s smaller than the pes anserinus bursa, and sometimes the two sacs can be connected. However, they don’t usually communicate with the knee joint itself, which makes their role in moving and protecting the knee somewhat unique.

Pes anserine bursitis refers to inflammation of the sac located beneath the pes anserinus. This condition is more common in middle-aged, overweight women. It causes pain at the point where the tendons insert into the shinbone, typically triggered by activities like climbing stairs or getting up from a seated position.

Pes anserine bursitis is often linked with other knee problems, particularly osteoarthritis. This condition appears as sudden knee pain on the lower, inner side of the knee without any trauma. The condition usually goes away on its own, with treatments like exercise and stretching often helping to speed this up. The term “pes anserine pain syndrome” refers to a wider range of conditions that cause pain on the inside of the knee, and could include conditions beyond inflammation of the bursa. Differentiating between pes anserine bursitis and tendon inflammation can be a challenge, as the tendons and bursa are very close to one another. However, the treatment for both conditions is the same.

Pes anserine bursitis was first described in 1937 by Moschcowitz. It’s known for causing knee pain, especially in women, that’s triggered by climbing stairs and getting up from a seated position. Difficulty with bending the knee may also occur.

What Causes Pes Anserine Bursitis?

Pes anserine bursitis is a condition that is often due to continuous stress or a direct hit to the pes anserine bursa, a small fluid-filled sac at the inner part of your knee. If your hamstring muscles are tight, they can put too much pressure on this bursa, which can lead to irritation from friction. Direct injuries can also make the inflammation worse.

This condition is linked to other problems with the knee, like Osgood-Schlatter syndrome, suprapatellar plical irritation, and arthritis in some parts of the knee, all of which can make your hamstrings spasm. Having too much body weight or a knee that bends inward more than it should, particularly in middle-aged women, can increase the risk of getting this condition as well.

Having flat feet can also make you more likely to get pes anserine bursitis in both knees, because it changes the way your legs line up and puts more pressure on the inner side of your knee. Other things that can contribute to pes anserine bursitis include a direct hit to the knee, bone growths, and tight tendons.

Different things, both physical and lifestyle, can lead to pes anserine bursitis. Knee problems, obesity, and sports that need a lot of sideways movement, like basketball and racquet sports, are all things that can increase your risk.

Pes anserine bursitis is also common in patients with early stages of knee arthritis and in many patients with diabetes. Some research shows that about 25% to 33% of people with diabetes might have pes anserine bursitis. In one study of 94 patients with diabetes that doesn’t need insulin, 34 of them had pes anserine bursitis. This problem was more common in women (91% of cases) than in men (9% of cases). However, people in the study who didn’t have diabetes didn’t get pes anserine bursitis.

Risk Factors and Frequency for Pes Anserine Bursitis

Pes anserine bursitis is a condition that often affects overweight middle-aged women, especially those with knee osteoarthritis. The unique female anatomy, including wider hips and increased knee angulation, can put additional pressure on the pes anserinus, where the bursitis is located. But it’s hard to figure out exactly how many people in the wider population have it. This is partly because its symptoms are similar to other knee problems, so it often gets misdiagnosed as a different sort of knee pain.

Recent studies have highlighted a connection between pes anserine bursitis and knee osteoarthritis. Research by Uysal et al revealed that 20% of people with primary knee osteoarthritis also had pes anserine bursitis. They also noticed the more severe the osteoarthritis was the larger the bursitis tended to be. Similarly, a study by Kim et al showed that people with knee osteoarthritis were far more likely (17.5%) to have pes anserine bursitis than those without it (2.2%). People with knee pain were also more likely to have it than those without pain (14.4% vs 2.5%).

However, other data sources like medical imaging and healthcare statistics don’t necessarily align with these figures. A review of 509 MRI scans of adult knees with symptoms found pes anserine bursitis in only 2.5% of cases. Another study of the US Military Health System identified it in only 1.4% of 127,570 patients with nonspecific knee complaints over two years. These differences highlight the challenges faced in diagnosing and documenting this condition.

Signs and Symptoms of Pes Anserine Bursitis

Pes anserine bursitis usually occurs in middle-aged women who have risk factors such as knee osteoarthritis, obesity, frequent participation in sports, and valgus knee (a condition where the knee angles inwards). A sudden severe pain in the inner side of the knee is the main symptom. This pain may get worse when standing up from a seated position, climbing stairs, or sitting with crossed legs. Sometimes, the pain begins after an injury. The pain can last, and become associated with mild redness and swelling, over hours or days. But it can also come and go for several months.

People engaged in sports such as running, basketball, soccer, and racket sports are particularly susceptible to this condition. Swimmers may also experience a related condition called “Breaststroker’s knee” that also presents with inner knee pain, often linked to strains of a knee ligament (MCL), but can be due to pes anserine bursitis too. In fact, having both these conditions together is not rare.

On a physical examination, the doctor will look for pain and tenderness on the inner side of the knee, especially when the knee is fully straightened. The pain is generally felt approximately 2-3 inches below the inner edge of the knee joint, where a group of tendons attach. Beneath these tendons lie the pes anserine bursa, which can be felt if there is fluid and thickening. The doctor may also be able to feel a grating sensation under the skin, suggesting bursitis. Pain can sometimes make the affected muscles weak and reduce knee movement.

The condition can also cause pain at the back or middle of the knee, like what is seen in knee cartilage injuries. Increased tenderness going up into the thigh, especially noticeable when the knee is bent to 90 degrees, could indicate a concurrent inflammation of the hamstring tendons.

To make sure it’s pes anserine bursitis and not another issue, doctors might press on different part of the knee. Pain along the inner edge of the joint might point to a cartilage tear, although some people might not feel anything even with this injury. An injury affecting the MCL due to inward pressure (valgus stress), common in athletes, usually causes tenderness slightly above and behind the pes anserine bursa.

The doctor may also measure the angle between the thigh and the lower leg. If this angle is more than 15-20 degrees when the hip is lift to 90 degrees and then the leg is straightened, it means the hamstring is too tight which can worsen the inflammation around the bursa. Other potential causes of pain in the same area include a bony growth of the shin bone, pressure on a nerve by the inflamed bursa, and a stress fracture of the shin bone.

In people injured during sports, pain might be caused by rotating the knee inwards and bending it. But in older adults with chronic bursitis, the pain and swelling around the bursa usually does not occur with knee bending or straightening.

Testing for Pes Anserine Bursitis

Pes anserine bursitis, a condition that causes pain and swelling in your knee, is typically diagnosed by your doctor based on your symptoms alone. However, they might employ some additional diagnostic tools if your case is complicated or unusual. One such tool could be an x-ray of your knee to check for any abnormalities in your bones like osteoarthritis.

In certain instances, your doctor might inject a numbing drug (lidocaine), with or without a steroid, directly into the swollen area of your knee. This injection serves two purposes – it relieves your discomfort confirming that you indeed have pes anserine bursitis, and allows the doctor to establish how much your knee issues can be attributed to this condition.

There are three primary imaging techniques that doctors use to get a clearer picture of the pes anserine bursa, the area causing discomfort due to this condition – they are x-ray imaging, ultrasonography, and MRI. The method selected depends on several factors like the resources available, the severity of your discomfort, and your specific medical circumstances.

X-ray imaging is typically done to rule out any abnormalities in your bones that could be aggravating your condition. Ultrasonography helps in locating any abnormal swellings in your knees. However, this method is not always reliable as the results often overlap with other conditions that might be causing the swelling in your knee.

An MRI is typically used to distinguish pes anserine bursitis from other knee issues. However, even this method has its limitations as it might identify fluid-filled bursae even in knees without any discomfort. Therefore, an MRI may not be able to confirm the diagnosis on its own.

In cases where the doctor suspects a more serious condition like an infection or tumor, they might perform additional tests like blood tests, fluid analysis, or biopsy. These tests are not routinely performed and are determined based on the patient’s medical history, physical examination results, and initial imaging results. If an infection is suspected, the doctor will measure your red blood cell count and C-reactive protein level, apart from performing an aspiration with fluid analysis. A biopsy is recommended if there is suspicion of cancer.

Treatment Options for Pes Anserine Bursitis

Pes anserine bursitis, an inflammation of a small fluid-filled sac beneath the knee, is usually self-healing, and patients often get better by just following simple, non-invasive treatments like physical therapy, regular stretching, rest, ice packs, and non-steroidal anti-inflammatory drugs (NSAIDs). These physical therapies not only speed up healing but also help prevent future injuries among athletes.

Treatment usually starts with rest, cooling the area with an ice pack, and taking NSAIDs for a short period, unless the patient has a medical condition that stops them from taking these drugs. Cutting down activities that aggravate the symptoms helps a lot in getting better.

Physical therapy is vital in managing the condition. The therapy helps stretch and strengthen the leg muscles, especially those involved in moving the knee. Similarly, it’s important to manage other medical conditions that might increase the risk of pes anserine bursitis, like arthritis, knee misalignment, obesity, and flat feet. Adopting a healthy lifestyle, maintaining a healthy weight, and using corrective orthopedic measures boosts recovery.

If the basic therapies don’t alleviate the symptoms, more advanced treatments are considered. These include the use of ultrasound or electrical stimulation, which are reportedly efficient in reducing inflammation, or extracorporeal shock wave therapy and kinesio taping, which help reduce pain and swelling in severe cases.

For persistent or severe cases, injecting local anesthetics or corticosteroids (drugs that reduce inflammation and suppress the immune system) into the inflamed bursa can significantly relieve pain. However, these injections can sometimes lead to complications like thinning of subcutaneous tissue, skin color changes, and tendon rupture. Hence, limiting the number of injections to not more than three per year can reduce these risks.

Surgery is rarely needed to treat pes anserine bursitis and is commonly reserved for cases that do not improve with other treatments. The surgery might involve either draining fluids from the inflamed bursa or removing the bursa altogether. After the surgery, the patient might need to keep the knee immobilized and restrict physical activity for some time.

For athletes, it might be necessary to adjust their activities and wear protective padding over the knee to avoid further injury. They can usually go back to play once symptoms resolve, but severe cases might need longer breaks from sport.

What else can Pes Anserine Bursitis be?

When diagnosing pes anserine bursitis, a condition which causes pain in the knee, many other issues must be considered because they can cause similar symptoms. The likelihood and frequency of these conditions vary.

More common conditions include:

• Medial meniscus injury: Often leads to knee pain, or the sensation of the knee locking or catching.
• MCL Injury: This often results from a physical injury and typically requires an MRI for diagnosis.
• Other types of knee bursitis: This can be identified by the specific location and pain points in the knee.
• Proximal tibial stress fracture: This typically occurs due to trauma or repetitive sports activity, and may cause similar pain.
• Saphenous nerve compression: This can lead to pain and a “pins and needles” sensation that flows downwards in the leg.

Less common, but still possible conditions include:

• Spontaneous osteonecrosis: This can cause severe, constant knee pain, and is distinguishable from pes anserine bursitis by using an MRI.
• Hamstring or semimembranosus tendinitis: Symptoms include swelling and tenderness in the hip or leg muscles.
• L3 to L4 radiculopathy: This condition, related to the lower spine, can cause pain that flows downwards but does not result in tenderness in the pes anserine bursa.
• Gout and pseudogout: This knee inflammation can reduce the ability to bear weight or move the knee fully, and is typically identified via certain presentation symptoms and lab tests.

Rare or unusual conditions also include:

• Knee cysts: These can be identified by their specific locations and symptoms.
• Tumors: These can range from benign to malignant and include a variety of different forms.
• Vascular issues: These can be relevant if there has been trauma to the vessels in the knee.
• Fibromyalgia: This typically presents with symmetrical, bilateral pain often in patients who are overweight.
• Miscellaneous conditions: These can include anything from patellar tendinitis to different synovial conditions, each with its own unique clinical features.

Identifying these conditions requires a detailed clinical examination and the use of appropriate diagnostic studies to differentiate them from pes anserine bursitis.

What to expect with Pes Anserine Bursitis

Pes anserine bursitis, a type of knee inflammation, typically improves on its own and usually doesn’t require surgery. With the right approach to management, like avoiding overuse of the joint, the long-term outlook for this condition is positive.

The duration of symptoms can vary according to factors like associated osteoarthritis, obesity, and a general lack of physical conditioning. Identifying and properly treating any related arthritic conditions can greatly reduce pain and improve overall physical functionality.

Athletes with pes anserine bursitis rarely experience long-term effects, even if they continue playing sports. A planned 6 to 8 week routine focusing on stretching and strengthening exercises for the muscles at the back side of the body can successfully reduce symptoms and allow athletes to return to their sports activities.

Possible Complications When Diagnosed with Pes Anserine Bursitis

Pes anserine bursitis is mainly a condition that resolves by itself and doesn’t tend to get worse. However, if the bursa, which is a small fluid-filled sac in the knee, remains inflamed and painful for a long time, it could impact the way a person walks. This altered walking style or a decrease in activity levels may lead to the weakening of the muscles that are supposed to stabilize the knee, a condition known as disuse atrophy.

This can be summarized as follows:

• Pes anserine bursitis usually doesn’t progress further.
• Chronic inflammation and pain can change a person’s walk.
• The changed gait or lower activity can weaken knee-stabilizing muscles.
• This weakening of muscles due to lack of use is called disuse atrophy.

Preventing Pes Anserine Bursitis

To prevent pes anserine bursitis, a condition that causes pain in the lower part of your knee, it’s important to manage certain risk factors. Here’s what you can do to take care of your knees:

* Keep a healthy weight to reduce stress on your knees
* Be smart about your workouts
* Always stretch and warm up properly before starting any physical activity to avoid injury
* Correct issues with how your body moves
* Pick the right shoes for your feet and your activity
* Slowly increase how hard your workouts are
* Always make sure you’re standing, sitting, and moving in a way that’s good for your back and joints
* Drink enough water to stay hydrated

In terms of preventing the condition from returning once you’ve got it, it’s about educating yourself. Knowing how to prevent further injury and when it’s safe to make a comeback in sports is crucial. Here’s what you should focus on:

* Make sure you train using the correct techniques
* Do exercises that stretch your hamstrings and strengthen your quadriceps, two major sets of muscles in your legs
* Pick the right shoes for your workout intensity and duration
* Maintain a healthy body weight

Taking the time to rest during the initial stages of pes anserine bursitis is also important. You may also be given special exercises to do at home to prevent muscle wasting, especially if you’re an older adult with arthritis. If you’re involved in sports, trainers and coaches need to know the importance of gently upping the level and amount of activity over time. Remember, combining these habits often works better than relying on one alone.