Iliopsoas tendinopathy/bursitis

What is iliopsoas tendinopathy/bursitis?

The iliopsoas tendon is formed by two muscles that run within the pelvis and the lower abdomen, “called iliacus and psoas muscles”. They are the main two muscles responsible for hip flexion (the movement that happens when you bring your knee toward your chest). Repetitive movements that involve hip flexion (for example, running) can cause tendon irritation and inflammation. Sometimes, fluid accumulates adjacent to the psoas tendon in a small sac “called the psoas bursa” at the front of the hip. This process of bursal inflammation can result in pain at the front of the, referred to as “psoas bursitis”.

Relevant Iliopsoas anatomy

The iliopsoas tendon is a combined tendon for two muscles (the psoas and the iliacus). Both are important hip flexor muscles. The psoas muscle runs at the side of the lower (lumbar spine) adjacent to the vertebrae. The iliacus muscle starts within the pelvis, and its tendon joins the psoas tendon to form the common “iliopsoas” tendon. Then the iliopsoas tendon runs at the front of the hip and continues to attach to a small bony prominence “called the lesser trochanter” located within the inner and upper aspect of the thigh bone, “the femur”.

The muscle has mainly two functions:

Hip flexion. This is your movement if you bring your knee toward your chest.

Core and hip stabilisation. The muscle runs on either side of the lumbar spine and within the pelvis. It is a crucial core stabiliser to the lower spine and hip.

What are the causes of Iliopsoas tendinopathy/bursitis?

There are mainly two types of patients that we usually see in our practice with iliopsoas (hip flexors) pain. These include:
1. People who perform repetitive movements/activities that involve hip flexion, particularly in sports like running and swimming. The iliopsoas tendon and the bursa can get inflamed due to repetitive movements that tend to overload the tendon. There could be an underlying biomechanical issue/imbalance, or the repeated tendon overload is causing tendon/bursal inflammation with insufficient opportunity for the tendon to recover.

2. Following hip replacement. Sometimes the hip implant or the post-surgical changes can irritate the psoas tendon as it passes at the front of the prosthesis. We routinely see this in our practice, and it is reported to affect 4% of patients who had a hip implant.

Also, iliopsoas bursitis can be associated with hip joint inflammatory conditions like hip osteoarthritis and rheumatoid arthritis, as in approx. 15% of the population, there is a connection between the hip joint and the bursa. Therefore, an inflammatory process within the hip may cause iliopsoas bursal fluid accumulation.

How does iliopsoas tendinopathy happen?

Iliopsoas tendinopathy is usually a repetitive stress/overuse injury. The tendon passes at the front of the hip joint and gets activated in movements involving hip flexion. Therefore, it is liable for irritation or impingement at the level of the hip joint. Iliopsoas tendon inflammation in such cases is referred to as "tendonitis". Tendonitis is usually a self-resolving condition with adequate rest and activity modification. However, repeated tendon irritation, combined with inadequate rest, would interfere with the tendon's normal healing/recovery process. As a result, the tendon will get weakened and thickened. This process is referred to as "tendinopathy".

Iliopsoas tendinopathy is also reported to be a cause of hip snapping. Snapping is usually felt at the front of the hip and is usually painless but uncomfortable. To find out more, please see our article about hip snapping causes.

The iliopsoas bursa is a small sac containing fluid that can be seen adjacent to the psoas tendon at the front of the hip joint. This bursa is not usually present in healthy individuals. It is part of the body's response, trying to provide more lubrication and cushioning effect to the inflamed tendon. "Bursitis" refers to inflammation of the bursa.

How will you know if you have iliopsoas bursitis/tendinopathy?

The clinical features of iliopsoas tendinopathy are:

Pain at the front of the hip joint/groin
The pain usually worsens when performing activities that involve hip flexion (like hip movement when you are trying to get out of the car, going upstairs, and running).
The pain is usually dull and deep in nature. It can be associated with a click/snap.

What other conditions can mimic iliopsoas bursitis/tendinopathy?

Iliopsoas tendinopathy can be mistaken for other causes of pain at the front of the hip. These include:

Iliopsoas bursitis/tendinopathy vs greater trochanteric pain syndrome

Both conditions are primarily due to tendon or bursal abnormalities. Trochanteric bursitis (or greater trochanteric pain syndrome) is due to inflammation (tendinosis) of the gluteal tendons and the overlying trochanteric bursa. The main differentiating feature is the site of the pain. Iliopsoas tendinopathy/bursitis pain is usually felt deep at the front of the hip. Trochanteric bursitis pain is felt more at the side of the hip, over a bony prominence (called the greater trochanter).

How to diagnose iliopsoas bursitis/tendinopathy?

Iliopsoas tendinopathy/bursitis is usually suspected clinically and confirmed with imaging. Ultrasound is very useful in assessing the psoas tendon at the front of the hip for any tendinopathy changes. It can also detect the presence of bursal fluid. Doppler ultrasound assessment will be helpful to assess for any increased vascularity in the area, which would indicate active inflammation. Ultrasound will also assess the front of the hip joint for any joint fluid "called joint effusion". It is a useful tool to assess the snapping sensation around the hip and can often visualise the culprit tendon/structure responsible for the snap/click during hip movement. In addition, ultrasound is very useful in guiding injection therapy into the psoas tendon sheath or iliopsoas bursa. Ultrasound-guided injections are more accurate, with better outcomes and fewer side effects than injections without ultrasound imaging.

MRI is also a very useful modality for assessment. It will assess the tendons around the hip joint and the hip joint itself for any problem. However, it requires you to stay still for about 20 minutes inside the scanner, and it has limitations if there is a hip implant, as the images will be distorted. To find out more, please see our article about hip MRI.

A hip X-ray would assess the hip joint for any arthritic changes or any changes of femoral-acetabular impingement. It cannot assess for psoas tendon inflammation.

What is the treatment for iliopsoas bursitis/tendinopathy?

Treatment of iliopsoas bursitis usually starts using conservative options mainly in the form of physiotherapy. This usually consists of stretching exercises and patient education/activity modification. Soft tissue manipulation might be also used for the management. Oral anti-inflammatory tablets can be also useful in the management.

Ultrasound-guided injection therapy for iliopsoas tendinopathy/bursitis

If the above conservative measures do not result in a satisfactory response, particularly if your pain is interfering with your daily activities, sports, and sleep, then an ultrasound-guided injection can be considered. This usually consists of a small dose of steroid injected into the psoas tendon sheath or the inflamed bursa. A steroid is a strong anti-inflammatory treatment This should reduce the inflammation around the tendon and provides you with a window of opportunity to perform more effective rehabilitation.

Ultrasound guided psoas tendon sheath injection

Should injections for iliopsoas tendinopathy/bursitis be done under ultrasound guidance?

Yes. This is our routine practice, as plenty of evidence supports ultrasound guidance when performing musculoskeletal injections. The psoas tendon is a deep structure, and ultrasound guidance will ensure the delivery of the medicine into the targeted site, either into the psoas tendon sheath or the psoas bursa. Doing injections under ultrasound/imaging guidance allows for direct visualisation of the needle to ensure accurate placement into the area of pain/inflammation (like a bursa, an arthritic joint, or an inflamed tendon sheath). Ultrasound guidance results in more accurate, less painful, and faster procedures, with better outcomes than these injections without guidance. Ultrasound guidance avoids sensitive structures (like nerves and vessels) during the procedure.

What are the possible side effects of a steroid injection?

Generally, these injections are very safe and routinely done in our practice. There is a very small risk of infection (about 1:10.000). The injected area may feel sore for the first few days. This is referred to as (steroid flare) and can be seen after a steroid injection. The procedure will be explained to you in detail during your appointment and all your questions will be addressed. To find out more about cortisone injection in general, please see our FAQs.

How long will the effect of a cortisone injection last?

Current evidence suggests that cortisone can improve pain and function for up to 3 months, but in some cases, it can last longer. The injections usually also contain a local anaesthetic that provides immediate pain relief lasting a few hours.

How soon will a steroid injection start to work?

A steroid injection usually takes a few days (1-3) before you notice the effect, although sometimes the pain relief can start on the same day. More commonly, the injected area will feel sore for the first few days. This is referred to as (steroid flare) and can be seen after a steroid injection.

How many steroid injections can I have for iliopsoas tendinopathy/bursitis?

We advise reducing the number of cortisone injections if possible, by combining any injection therapy with an effective physiotherapy program to address the underlying cause. Repeated steroid injection into the same area should be avoided if the previous injection was less than 3-4 months ago.

How long should I rest after a hip steroid injection?

Usually, we advise patients to rest for 48-72 hours after having a hip injection. This can vary depending on the type of treatment and severity of the condition. Usually, patients who have a steroid injection are usually advised to rest for 48 hours.