Diagnosing and Treating Bone Marrow Oedema

Bone marrow oedema is swelling or fluid build-up within the bone marrow. Often, oedema is detected by imaging such as MRI. So, what is subchondral bone marrow oedema, and how should you manage it?

What is subchondral bone marrow oedema?

The bone marrow is the spongy part of the bone’s centre. It is involved in producing new red and white cells in the blood. A build-up of fluid in the bone marrow is often termed bone marrow oedema. Oedema usually occurs due to an injury, such as a fall, or pathological conditions, such as osteoarthritis or tumours.

How to diagnose bone marrow oedema  

Fluid build-up in the bone marrow is generally diagnosed through imaging such as an MRI. However, other imaging, such as X-rays or CT, can sometimes help make a specific diagnosis.

There are many causes of bone marrow oedema, but the most common causes include the following:

Osteoarthritis 

Osteoarthritis occurs when the cartilage becomes damaged due to degeneration and inflammation. Bone oedema is often a sign that your osteoarthritis has gotten worse.

Studies suggest that the presence of oedema means worse symptoms and a higher chance of progression than cases without oedema.

Acute injury

An acute injury such as a fall or twist can lead to bone marrow bruising, an acute fracture, or cartilage damage. Fluid build-up or release can occur secondary to bleeding, fibrosis (scar tissue), or necrosis (tissue death). This fluid in the bone can last long, meaning pain from a bone bruise can last for many months.

Stress fractures 

Repeated and sustained impact on bone can weaken it, leading to microfractures and fluid build-up in the bone marrow. This oedema is a stress response or fracture due to excessive physical activity such as running, football, or netball. A particular type of stress fracture in the knee called SONK or spontaneous osteonecrosis of the knee commonly affects women over the age of 60. It is often associated with meniscal tears and is more common in the medial femoral condyle. 

Tumours 

Tumour growth leads to fluid build-up and bone weakening. One particular tumour that causes intense bone marrow oedema is osteoid osteoma.

Infection 

Infection leads to acute inflammation and fluid build-up in the bone marrow.

Primary 

Sometimes, oedema forms for no known reason. This oedema is often termed primary bone marrow oedema of unknown cause or transient migratory osteoporosis. Generally, this condition affects the hips, knees, ankles, and feet. It rarely affects the bones of the upper limbs. Overall, it is essential to rule out the other causes of bone marrow oedema.

Primary bone marrow oedema is sometimes associated with metabolic disorders such as Vitamin D deficiency and osteoporosis. 

Assessment of Bone Marrow Oedema

Generally, your doctor will assess you to determine the cause of bone marrow oedema. Tests are usually required to find the cause, ranging from imaging (MRI/CT scan ), bone density scan (to look for osteoporosis) and blood (to look for inflammation or infection). 

Treatment of bone marrow oedema 

If the cause is due to trauma such as a fall, then treatment consisting of rest, ice, and NSAIDs will reduce swelling. Generally, most cases settle between three-and six months. Sometimes, swelling can last for more than a year.

We recommend rest using a walking aid or crutches in primary bone oedema (with no known cause). Ice and simple analgesic tablets will also help. Generally, we perform routine checks of bone density and blood tests such as inflammatory markers and vitamin D. There is a link between bone oedema and vitamin D deficiency. In addition, improving general lifestyle factors such as stopping smoking, increasing calcium intake, and reducing alcohol intake can help. 

Other frequently asked questions about Bone Marrow Oedema:

Is there a link between pregnancy and primary bone oedema?

Yes. Primary bone marrow oedema often affects women late in pregnancy. More commonly, it affects the hip joints, knees, and ankles.

How long does primary bone oedema last? 

Typically, symptoms last for 3-6 months. Sometimes, symptoms can recur or move to another joint.

Are injections indicated for bone marrow oedema? 

Generally not. However, in severe cases, we might consider intravenous bisphosphonates. In addition, if bone oedema occurs in the knee or the hip, we may consider a hyaluronic acid injection into the joint.

Osteoid Osteoma on MRI: What do we see? 

Osteoid Osteoma is a benign bone tumour often found in the pelvis or lower limb. Generally, pain is worse at night and better during the day. Also, Aspirin or Ibuprofen usually reduces pain. Osteoid Osteoma can be tricky to detect on MRI. Sometimes, It presents with a small area of bone marrow oedema or can be missed entirely. We often need other tests, such as a CT scan, to find the small core or nidus, confirming the diagnosis. 

Final word from sportdoctorlondon 

Bone marrow oedema is often seen on MRI scans. Therefore, it is essential to determine the cause of oedema to provide effective treatment.