Ultrasound guided pes anserine bursitis/tendinosis steroid injection

Ultrasound guided pes anserine steroid injection

What is pes anserine tendinosis/bursitis?

What is pes anserine bursitis/tendinosis?

The pes anserine refers to three tendons that have a combined attachment to the inner aspect of the leg, just below the level of the knee joint. These tendons are the gracilis, semitendinosus and sartorius tendons. The attachment of these tendons looks like a “Goosefoot”, meaning “pes Anserine” in Latin. The condition is occasionally referred to as lower Hamstring tendinosis. These muscles start in the thigh and are responsible for bringing the leg towards the midline (adduction) and also help in knee bending the knee (flexion). Pes anserine tendinosis results from inflammation of these tendons. Sometimes the term bursitis is also used. This refers to inflammation of the bursa (a thin fluid-containing sac) between the tendons and their attachment to the bone. The two conditions can overlap.

What is the cause of pes anserine bursitis/tendinosis?

The condition happens usually secondary to repeated overload of the pes anserine tendons during repetitive activities like running or activities that involve knee bending against resistance like squatting.

What are the features of pes anserine bursitis/tendinosis?

The usual symptoms of pes anserine bursitis/tendinosis are:

Pain at the inside of the leg, just below the knee joint.
Pain might be felt slightly higher up at the inner aspect of the lower thigh.
The pain usually gets worse after a period of rest and warms up with training.
Pain can also get worse with increased activity like running.
There might be associated swelling and stiffness at the inner aspect below the knee joint.

What conditions can mimic pes anserine bursitis/tendinosis?

Medial meniscal tear. This refers to a tear in a special type of tissue/cartilage at the inner aspect of the knee.
Medial knee osteoarthritis. Arthritis (wear and tear) changes to the inner part of the knee.
Patellofemoral (Knee cap) arthritis
Medial collateral ligament pain. This can happen due to a sprain of the ligament at the inner aspect of the knee.
Stress fracture.

What is the difference between pes anserine bursitis and a medial meniscal tear?

A medial meniscal tear usually results in pain in the inner aspect of the knee. In contrast, pes anserine bursitis pain is usually lower at the upper and inner aspect of the shin bone, just below the level of the knee joint. A meniscal tear most often occurs secondary to a twisting injury, while pes anserine tendinosis usually progresses gradually. A meniscal tear can be associated with locking and giving way (we refer to these as mechanical symptoms), while pes anserine tendinosis does not. Imaging is usually very useful in the assessment, particularly MRI knee examination.

To learn more, please read our article about pain in the inner aspect of the knee.

How to diagnose pes anserine bursitis/tendinosis?

When the diagnosis is suspected clinically, imaging is usually needed to confirm the diagnosis. An ultrasound examination performed by an experienced doctor is very useful to assess the pes anserine tendons for any inflammation and if there is any fluid within the pes anserine bursa. MRI can also be useful for the assessment. Ultrasound is particularly useful for accurately injecting the inflamed pes anserine tendons. The injection can be therapeutic (help with the pain) and diagnostic (confirm the diagnosis if you notice a good response from the injection).

How to treat pes anserine tendinosis/bursitis?

Treatment always starts with physiotherapy. This would include stretching exercises of the hamstring and adductor muscles and exercise modification to help rest the pes anserine tendons. Lower limb exercises aiming to increase strength and stability of the hip and knee are also useful for management, as well as using anti-inflammatory tablets.

Can a cortisone injection help in pes anserine tendinosis/bursitis?

Yes, injection therapy can be considered if the above treatment is not helping, especially if the pain significantly affects sleep, daily activities and your ability to exercise. An ultrasound-guided steroid injection can be very useful to settle down the inflammation in the area and allow for more effective physiotherapy and rehabilitation.

What is the benefit of having an ultrasound-guided injection for pes anserine tendinosis/bursitis?

There is significant evidence that when injections are done under ultrasound guidance, they result in better outcomes, with better pain relief and more improvement in function. This is particularly important here as the targeted area is small and the injectate needs to be administered exactly between the tendons and their attachment to the tibia bone.

What are the possible side effects of a pes anserine bursa steroid injection?

Most people tolerate the injection very well without any significant side effects. Possible side effects include Pain and discomfort at the site for a few days (steroid flare), focal skin colour changes and a minimal risk of infection. There is a possibility that the injection may not work for you. To find out more about corticosteroid injections, please see your FAQs.

Can pes anserine tendonitis happen after total knee replacement (TKR)?

It is not uncommon to feel pain in the region of pes anserine tendons following a total knee replacement; however, there are possible causes for pain at the inner aspect of the knee following a TKR. Clinical assessment and ultrasound examination will be useful for the assessment. An ultrasound-guided steroid injection to the pes anserine bursa is usually useful to confirm the diagnosis and relieve pain.

Is there a role for PRP injections in pes anserine tendonitis?

Ultrasound-guided platelet-rich plasma (PRP) injections can be considered, in certain cases, resistant to physiotherapy and cortisone injection, but it is not routinely done. PRP injection involves taking a small blood sample from you, which will be spun in a special machine (called a centrifuge) to separate it into different components. The plasma component can then be extracted and re-injected into the inflamed tendons to promote a natural healing process. The plasma contains high levels of growth factors, which are very useful for tissue healing.

Summary

We see pes anserine tendonitis/bursitis commonly in our practice. This is sometimes seen following total knee replacement. Imaging is essential to confirm the diagnosis and rule out other causes for pain in the inner aspect of the knee. Physiotherapy is very useful for treatment. An ultrasound-guided cortisone injection can be diagnostic +/- therapeutic.