Knee Bursitis (Hygroma): A Physiotherapist’s Complete Guide

Have you been diagnosed with (or do you think you have) knee bursitis (hygroma)?

It’s a pathology that is frequently seen as a physiotherapist. I’ve compiled here all the information I feel is important to know, based on international scientific publications.

♻️ Last update: July 14, 2024.
👩‍⚖️ Declaration of financial interests: none directly related to the subject. My complete declaration of financial interests is in the legal notice section.
Written by Nelly Darbois, physiotherapist and scientific editor

What are the different types of knee bursitis?

Various elements are present in our joints, such as the knee.

In particular, the bursae. These are small pockets filled with synovial fluid, a slippery, viscous liquid that acts as a cushion or shock absorber between tendons, muscles and bones.

Sometimes these bursae can swell due to the fluid that accumulates in them. This is called bursitis: literally, inflammation of a bursa.

As there are several bursae in the knee, bursitis has different names.

Name	Description (complete)
Pes anserine bursitis (crow’s feet bursitis)	Inflammation of the bursa between the thigh bone and the tendon of the semitendinosus muscle of the crow’s feet, below the knee on the inside.
Infrapatellar or subrotellar bursitis	Inflammation of the bursa under the patella.
Pre-shin or pre-patellar bursitis	Inflammation of the bursa in front of the patella.
Patellar bursitis	Inflammation of the bursa behind the patella.
Suprapatellar or patellar tendon bursitis	Inflammation of the bursa above the patella.
Bursitis of the medial ligament of the knee	Inflammation of the bursa located near this ligament
Iliotibial bursitis	This is the other name given to iliotibial band syndrome.
Infectious or septic bursitis	Inflammation caused by bacterial infection: much less frequent.
Bursopathy	General term for any condition or inflammation affecting the synovial bursa.
Hygroma of the knee	Abnormal accumulation of fluid in a knee bursa (synovial fluid, lymphatic fluid or blood).

Whatever the precise location of the bursitis, the course of action is the same.

Imaging tests such as X-ray or MRI are not recommended to diagnose bursitis, unless there is a suspicion of a fracture or other type of tissue lesion requiring different treatment.

The same applies to blood tests (to check for inflammatory markers), blood cultures or analyses of aspirated and sampled fluid, carried out to rule out infection only in the event of specific symptoms such as fever or a wound.

Source : Mohseni 2024

See also other possible locations of bursitis.

Why do some people get bursitis and others don’t?

Bursitis is more common in people who :

• have osteoarthritis of the knee;
• are obese;
• are female, especially for crow’s feet bursitis.

Bursitis is often triggered by trauma to the knee : a fall, twisting the knee while walking or playing sport.

Or from repeated but less significant trauma, for example when you increase the frequency or duration of sports sessions a little too quickly, even though you’re not used to this training load.

Sometimes, inflammatory diseases such as rheumatoid arthritis are the cause.

Source : Mohseni 2024

Infected bursitis most often occurs as a result of microtrauma or direct perforation of the skin. They are more common in men aged around 50 [Truong 2023].

How long does it take for bursitis to heal?

There are no studies tracking the evolution over weeks of people diagnosed with knee bursitis.

My experience as a physiotherapist has led me to meet people who have been genitalised for just a few days, and others for years, with inflammation that comes and goes.

Here’s what academic publications say about recovery time, prognosis and evolution:

In most cases, crow’s feet bursitis can be managed non-surgically. The long-term prognosis of this condition is favorable, particularly when exacerbating factors such as overuse of the joints are avoided.

Mohseni 2024

If the area is rested, the inflammation generally disappears within 2 or 3 weeks. Sometimes, however, it may persist permanently, for example because the person continues (or has to continue) the activity that caused it.

Chronic illnesses such as diabetes and rheumatoid arthritis can also delay healing and even aggravate inflammation.

InformedHealth 2018

Infected bursitis:

Most patients are treated on an outpatient basis, but the duration of treatment remains unknown.

Because of the risk of osteomyelitis, these patients should be closely monitored.

The duration and type of treatment are the subject of debate.

Recommendations include a minimum of 10 days’ treatment in mild cases, and repeated aspirations and continued antibiotics until the bursal fluid is free of infectious signs in severe cases.

Truong 2023

What treatments are available?

In the vast majority of cases, conservative treatment is proposed: no surgery on the knee.

Whatever the location of the bursitis.

Resting the knee?

Resting the knee means avoiding or limiting activities that increase pain.

Much depends on your basic level of activity.

If you’re a very sporty person (e.g. 5 running and cycling sessions a week), you don’t necessarily have to stop altogether. But you will need to find the right frequency and intensity of activity that causes virtually no knee pain during or after the activity.

If you normally do little or no physical activity, you’ll need to identify the work or leisure activities that increase your symptoms (pain, swollen, hot and red knee, etc.) and try to reduce them.

This could be walking, prolonged static standing, squatting, etc.

Stopping over-activity by resting the joint can help reduce inflammation. The fluid contained in the bursa will evacuate over time, passing through the body’s various tissues.

When you feel that your symptoms are easing, you can gradually increase the amount and duration of activity involving your knee.

Applying cold to the painful area can also bring relief, at least for the moment.

Exercise or physical therapy?

In France, physiotherapy sessions are often prescribed for knee pain.

Physiotherapists are among the health professionals who can help youidentify the right level of physical activity for you, based on the difficulties you are experiencing.

Your physiotherapist may also suggest various techniques to relieve pain: therapeutic ultrasound, shockwave therapy, massage, TENS, cryotherapy, manual therapy, etc.

Although we don’t have any high-quality randomized controlled trials showing the significant benefit of using these techniques versus simply reassuring and supporting the gradual resumption of triggering activities.

Some physiotherapists will also suggest muscle-strengthening exercises for the leg muscles. Here again, there are no randomized trials showing a significant improvement in symptoms when exercises are performed versus when they are not.

Are there any natural remedies?

As with the devices and techniques often used by physiotherapists, there are no clinical trials to show any significant effect of the various natural anti-inflammatory remedies: green clay poultices, lavender essential oil, tiger balm, dietary supplements or omega-3 fatty acids, etc.

Personally, it’s not something I use or recommend to people who seek my physiotherapy advice. Although I can understand why people might want to try this kind of thing.

What medical and surgical treatments are available?

In the case of bursitis of infectious origin, antibiotics are prescribed [Truong 2023].

Even in the case of non-infectious bursitis, some people may want to try more than “just” letting time take its course, doing physiotherapy and modulating their activity level to get better.

Treatments are sometimes proposed by general practitioners, sports medicine specialists, rheumatologists or orthopaedic surgeons:

• taking oral anti-inflammatory drugs (NSAIDs) or analgesics (paracetamol);
• injections of corticosteroids and anaesthetics into the knee joint, directly into the bursa;
• arthroscopic bursectomy: incision and drainage of the bursa.

Again, these treatments have not been rigorously evaluated in randomized clinical trials. They carry a higher risk of potential side effects, and are not recommended as first-line treatments.

Source : Mohseni 2024

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That’s all I wanted to say on the subject! Any questions or comments? See you in comments!