Knee pain located at the lower inside of the knee can be caused by Pes Anserine Bursitis, which is irritation of the tendons that run on the inside aspect of the knee. Commonly mistaken for arthritic pain, meniscal pain, and sometimes nerve pain from the low back! Don’t be misdiagnosed, and let’s dive in below to get a better understanding of Pes Anserine Bursitis.
What Is Pes Anserine Bursitis?
The Pes Anserine Bursa is a bursa that surrounds 3 tendons of the leg. A bursa is a thin, slippery, sac-like film that contains a small amount of fluid. A bursa is found between bones and soft tissues in and around joints. It cushions and protects joint structures and stops them from rubbing against each other. If a bursa becomes inflamed and irritated, it’s known as bursitis.
The Pes Anserine Bursa surrounds 3 tendons as they attach a few inches below the medial (inside) knee joint:
- Sartorius: Synergistic muscles that can help flex, abduct and rotate the femur. It can also flex and medially rotate the leg. Sitting cross-legged demonstrates all four actions of the Sartorius.
- Gracilis: The most superficial and medial of the muscles at the medial compartment of thigh. The muscle adducts, medially rotates (with hip flexion), laterally rotates, and flexes the hip as above, and also aids in flexion of the knee.
- Semitendinosus: The Semitendinosus muscle is one of three hamstring muscles that are located at the back of the thigh.
These three muscles work collectively to flex the knee and extend the hip. All 3 of the muscles that make up the Pes Anserine are unique in that they cross both the hip and knee, meaning they can move both joints (hip and knee).
Symptoms of This Condition
One of the hallmarks and distinguishing aspects of Pes Anserine Bursitis is that the knee pain is below the medial (inside) joint line. You can easily palpate the joint line of the knee and then 2 to 3 inches below the knee joint on the inside of the lower leg.
Pain And Tenderness Inside The Knee
Palpate the 2-3 inches below the joint line (see Figure 1), and if this area is very tender to even light touch, it is highly likely that you can have Pes Anserine Bursitis.
The Pes Tendons Get Irritated with Repetitive Motion / Knee Flexion.
When inflamed, the pain increases with exercise or climbing stairs but if there is excessive inflammation, pain can be at rest with the knee flexed, such as in sitting position.
Common Causes of Pes Anserine Bursitis
Tendons of the Pes Anserine act on both the hip and knee, so repetitive motion and overuse of both the hip and knee can lead to excessive stress on the tendons.
Overuse Seen in Multiple Movements
We see a lot of athletes, but they are not the only ones that do repetitive activities. Repetitive activities, like squatting, stair climbing, and other work or household activities can be the cause of overuse of a joint.
Osteoarthritis
Numerous studies have shown the strong association of Pes Anserine Bursitis in Osteoarthritis patients.
Incorrect Physical Training Techniques
This can include things such as a lack of stretching, big distance jumps in training, or too much uphill running.
Tight Hamstring Muscles
Tight hamstrings are a common cause of Pes Anserine Bursitis.
Obesity
Examination and Diagnosis
Getting the correct diagnosis is key! Getting to the right diagnosis takes time to discuss your pain. We typically begin with determining the “OLD CARTS” which is a cheat code for recalling the history of your pain, and it stands for Onset, Location, Duration, Characterization, Aggravating, Relieving, Treatments and Severity. This information quickly gives insight into a possible diagnosis.
Next comes the examination part, inspecting for any abnormal alignment (valgus or varus), palpating all structures around the knee, and putting the knee through stress maneuvers to see if anything recreates the pain.
Lastly during evaluation any sports medicine or musculoskeletal doctor (PM&R, orthopedic surgeon) when evaluating any knee conditions has to use diagnostic ultrasound during their evaluation and examination. This can easily help differentiate say a meniscus tear versus Pes Anserine Bursitis (see Figure 2, below). Diagnostic ultrasounds are now a standard of care for most orthopedic problems, helps coming up with a concrete diagnosis during your visit so we can move forward talking about how best to treat the problem to get you back to doing what you love to do, without pain.
Once we have a solid diagnosis of Pes Anserine Bursitis, we can move on to discussing the more important issues – like how to treat it! Bursitis = inflammation of the bursa which can come from overuse / repetitive trauma or from the Pes tendons becoming damaged and swollen. Treatments start with conservative care and then increase invasiveness.
- Rest it for a few weeks to allow the body to take care of it.
- Ice Packs or Heat packs can help calm down the inflammation.
- Anti-inflammatory Medication both over the counter or supplementations – to learn more about best options read a previous blog about NSAIDs:
- Physical Therapy can help increase the strength of the Pes tendons and use modalities to help flush the inflammation out.
- Anesthetic and Steroid Injections can help temporarily and as well confirm the diagnosis if all the pain goes away but any injection should be done under ultrasound guidance to avoid the nerves / vessels of the area and to NOT get in the tendon …. Potentially for tendon rupture if that happens!
- Surgery is rarely needed for Pes Anserine Bursitis but many more invasive procedures can be done such as Radio Frequency Ablation (RFA) to the local nerves to dull the pain (1).
Regenexx: A Revolutionary Treatment Method
Over the last 20 years, research has gone beyond corticosteroids for orthopedic injuries. The development of Platelet-Rich Plasma has successfully been able to help most orthopedic conditions as well as reduce the surgical conversion rates of common tendon issues like Pes Anserine Bursitis! Being the HQ of Regenexx, we continue to research how to maximize the concentration and tailor-make our PRP treatments to specific orthopedic conditions, thus maximizing our clinical results.
“Patient outcomes are the #1 priority at Regenexx. Our lab processing of blood platelet mixtures is far more labor intensive than the automated centrifuge used by others, but we are able to create customized solutions for our patients, with platelet mixtures that are purer and more concentrated.”
Dr. Chris Centeno
Over the last 15+ years, Regenexx has pioneered orthobiologics with maximization of outcomes using the most up-to-date precise ultrasound-guided imaging to ensure we treat the right area! We have termed this as “Interventional Orthopedics” To learn more about these advanced image-guided treatment options.
Is Pes Anserine Bursitis Preventable?
Seeing a physical therapist can set you up with a home exercise program to strengthen and stretch the muscles around your knees, upper legs, and abdomen to help prevent the onset or recurrence of Pes Anserine Bursitis. Working on mobility, stability, and strength of the kinetic chain can help prevent not only Pes Anserine Bursitis but also reduce the risk of multiple other injuries in your lower extremities.
Here’s a Simple Checklist:
- Learn correct knee positioning when participating in athletic activities.
- Follow a consistent flexibility and strength exercise program, especially for the leg and hip muscles, to maintain good physical conditioning.
- Practice balance and agility exercises and drills.
- Always warm up before starting a sport or heavy physical activity.
- Avoid sudden increases in running mileage or uphill running, gradually build loads over time.
- Wear shoes that are in good condition and fit well.
- Maintain a healthy weight and eliminate high sugar foods and processed foods.
- Treat and manage Diabetes, as managing your glycemic control helps prevent musculoskeletal injuries.
- Wear orthotics to reduce flat feet and valgus (knock-knee) positioning of the lower extremities.
- Wear a knee brace to support the knee and reduce strain on the inside of the joint when doing high stress activities.
Recovery Period
For tendons (like in Pes Anserine Bursitis) the soreness can last longer and the effects could take up to 3-4 months to be fully appreciated. For ligaments, there may be a “honeymoon” period of 1-2 weeks where loose ligaments are swollen and as such, provide better stability during that time, but then the initial swelling goes away and the pain and instability come back (2). The full effects, like in tendons, can take a few months to be seen.
BUT Not All PRP Is Created Equal.
There are two main types of PRP: red and amber. Red PRP has red and white blood cells, so in my experience, it causes more of a flare-up for longer. Amber PRP has few red or white blood cells, so it causes less of a flare-up and if that happens, the flare-up doesn’t last as long.
Also, realize that the degree of post-PRP injection flare-up can be due to your body’s own level of systemic inflammation and where the PRP was injected, or how aggressively the procedure disrupted the tissues.
Successful Treatment Is Possible for Pes Anserine Bursitis
At Centeno Schultz Clinic, we have dedicated our practice to delivering the highest quality orthopedic care possible. We have a three-prong approach:
- Spending an hour with patients during initial evaluations to ensure we have the most accurate diagnosis and discussing all options with patients to develop a comprehensive treatment plan (which may or may not include biologics).
- Continuing research in biologic therapy such as PRP and Bone Marrow Concentrate (containing stem cells) utilizing our Flexible Lab Platform to maximize platelet-based therapies and beyond.
- Continuing to innovate injection techniques to ensure precision guidance of biologics to target areas. All physicians at CSC are trained in both xray based and ultrasound image guidance to ensure the best possible treatment for your knee condition.
If you have been dealing with Pes Anserine Bursitis or an orthopedic condition and would like an in-depth evaluation with a comprehensive treatment plan, sign up for an evaluation today!
References
- Conger A, McCormick ZL, Henrie AM. Pes Anserine Tendon Injury Resulting from Cooled Radiofrequency Ablation of the Inferior Medial Genicular Nerve. PM R. 2019 Nov;11(11):1244-1247. doi: 10.1002/pmrj.12155. Epub 2019 May 24. PMID: 30859692.
- Xu Q, Chen J, Cheng L. Comparison of platelet rich plasma and corticosteroids in the management of lateral epicondylitis: A meta-analysis of randomized controlled trials. Int J Surg. 2019 Jul;67:37-46. doi:10.1016/j.ijsu.2019.05.003