Bone marrow oedema is swelling or fluid build-up within the bone marrow. It’s usually detected on imaging, particularly MRI. So what is subchondral bone marrow oedema, what causes it, and how should you manage it?
What is subchondral bone marrow oedema?
The bone marrow is the spongy part at the centre of the bone, involved in producing new red and white blood cells. A build-up of fluid there is called bone marrow oedema. “Subchondral” means the oedema sits in the bone just beneath the cartilage of a joint. It usually occurs after an injury, such as a fall, or from conditions such as osteoarthritis or tumours.
How to diagnose bone marrow oedema
Fluid build-up in the bone marrow is generally diagnosed on imaging, usually an MRI. Other imaging, such as X-ray or CT, can sometimes help pin down the specific cause.
There are many causes of bone marrow oedema. The most common include the following.
Osteoarthritis
Osteoarthritis occurs when cartilage is damaged by degeneration and inflammation. Bone oedema is often a sign that the osteoarthritis has worsened. Studies suggest that when oedema is present, symptoms tend to be worse and the arthritis is more likely to progress than in cases without it.
Acute injury
An acute injury, such as a fall or twist, can cause bone marrow bruising, an acute fracture, or cartilage damage. Fluid can build up secondary to bleeding, scar tissue (fibrosis), or tissue death (necrosis). This oedema can last a long time — which is why pain from a bone bruise can persist for many months.
Stress fractures
Repeated, sustained impact can weaken bone, leading to microfractures and fluid build-up in the marrow. This is a bone stress response or stress fracture from excessive activity such as running, football, or netball. A particular knee stress fracture — SONK, or a subchondral insufficiency fracture of the knee — commonly affects women over 60, is often associated with meniscal tears, and typically affects the medial femoral condyle.
Tumours
Tumour growth causes fluid build-up and weakens the bone. One tumour that causes intense bone marrow oedema is an osteoid osteoma.
Infection
Infection causes acute inflammation and fluid build-up in the bone marrow.
Osteonecrosis (avascular necrosis)
When the blood supply to a section of bone is interrupted, the bone begins to die — a condition known as osteonecrosis, or avascular necrosis (AVN). Bone marrow oedema is one of the earliest signs of AVN on MRI, appearing well before the bone collapses. This is an important cause to identify early because catching AVN before collapse allows for joint-preserving treatment. It’s a particular consideration when subchondral oedema appears in the hip.
Primary (no known cause)
Sometimes oedema forms for no clear reason — termed primary bone marrow oedema of unknown cause, or transient osteoporosis of the hip. It usually affects the hips, knees, ankles, and feet, and rarely the upper limbs. It’s essential to rule out the other causes first. Primary bone marrow oedema is sometimes linked to metabolic problems such as vitamin D deficiency and osteoporosis.
Assessment of bone marrow oedema
Your doctor assesses you to determine the cause. Tests are usually needed, ranging from imaging (MRI or CT) to a bone density (DEXA) scan to look for osteoporosis, and blood tests to look for inflammation or infection.
Treatment of bone marrow oedema
Treatment depends on the cause.
Where it’s due to trauma, such as a fall, rest, ice, and NSAIDs reduce the swelling. Most cases settle between three and six months, though swelling occasionally lasts more than a year.
In primary bone oedema (transient osteoporosis of the hip), we recommend rest using a walking aid or crutches, along with ice and simple painkillers. We routinely check bone density and run blood tests, including inflammatory markers and vitamin D levels, given the link between bone oedema and vitamin D deficiency. Improving general lifestyle factors — stopping smoking, increasing calcium intake, and reducing alcohol — also helps.
Frequently asked questions about bone marrow oedema
Does bone marrow oedema mean I have arthritis?
Not necessarily. Bone marrow oedema has many causes — injury, stress fracture, infection, tumour, and primary (unknown) causes — as well as osteoarthritis. When it does occur alongside arthritis, it tends to signal more active or advancing disease. That’s why identifying the cause matters more than the oedema itself.
Is bone marrow oedema serious?
It depends entirely on the cause. Many cases (bruising, primary oedema) settle within months with simple treatment, while others (a stress fracture, infection, or tumour) need specific management. Because the causes range from benign to serious, an accurate diagnosis is essential.
Can I exercise or weight-bear with bone marrow oedema?
It depends on the cause and location. Some causes — a stress fracture or a subchondral insufficiency fracture — need offloading with crutches or a walking aid, whereas milder bruising may allow gentle activity. Always get the cause diagnosed first, as loading the wrong type can worsen it.
Is there a link between pregnancy and primary bone oedema?
Yes. Primary bone marrow oedema often affects women late in pregnancy, most commonly in the hips, knees, and ankles.
How long does primary bone oedema last?
Usually 3–6 months. Sometimes symptoms recur or move to another joint.
Are injections indicated for bone marrow oedema?
Generally, no. In severe cases, we might consider intravenous bisphosphonates. And where bone oedema occurs in the knee or hip alongside arthritis, we may consider a hyaluronic acid injection into the joint.
Osteoid osteoma on MRI: what do we see?
An osteoid osteoma is a benign bone tumour, often in the pelvis or lower limbs, that classically causes pain worse at night and relieved by aspirin or ibuprofen. It can be tricky to detect on MRI — sometimes showing only a small area of bone marrow oedema, or being missed entirely — so a CT scan is often needed to find the small core (nidus) and confirm it.
Final word from Sport Doctor London about bone marrow oedema
Bone marrow oedema is a common MRI finding, so determining its cause is key to effective treatment. Primary bone marrow oedema, or transient osteoporosis of the hip, is managed differently from the other causes — which is why an accurate diagnosis comes first.
If a scan has shown bone marrow oedema, Dr Masci can assess you in London and arrange the right tests to find the cause. Contact the team here or call +44 (0) 203 488 0350.
Have you got experience with transitory osteoporosis?
If so, what kind of treatment would you recommend?
Have you got experience with hyperbaric O2 treatment?
Thank you!
Hi Maria,
As discussed in the blog, I use simple treatments such as partial weight-bearing and simple analgesia (not ibuprofen) until the pain settles. It is critical to check bone health to exclude generalised osteoporosis—I perform blood tests and a DEXA scan. If the vitamin D level is low, I use vitamin D supplements.
I have no experience with hyperbaric O2
Lorenzo
An MRI has shown that i have bone marrow oedema in my C5/6 and C6/C7 following a fall on my left side. I have severe pain and tingling down my left arm. My doctor has prescribed Entrip but I’m reluctant to take any more medication. She said I’ll need another MRI in 3 months time. Will physiotherapy help?
Hi Rhonda, Yes if your doctor has definitely excluded a fracture, then physiotherapy may help. LM