An edema is a buildup of fluid. A bone marrow edema — often referred to as bone marrow lesion — occurs when fluid builds up in the bone marrow. Bone marrow edema is typically a response to an injury such as a fracture or conditions such as osteoarthritis. Bone marrow edema usually resolves itself with rest and physical therapy.

Bone marrow edemas are typically found with an MRI or ultrasound. They can’t be seen on X-rays or CT scans. They’re typically diagnosed when a patient has another condition or pain in or around the bone.

Bone marrow is made up of bony, fatty, and blood cell–producing material. Bone marrow edema is an area of increased fluid inside the bone. Causes of bone marrow edema include:

  • Stress fractures. Stress fractures occur with repetitive stress on the bones. This can occur due to physical activity such as running, competitive dancing, or weightlifting. The fractures are characterized by bone edema and fracture lines.
  • Arthritis. Bone edemas are relatively common in those who have both inflammatory and noninflammatory arthritis. It’s usually due to a cellular infiltrate within the bone which compromises bone cell function.
  • Cancer. Metastatic tumors can produce a higher water production in bone. This edema will appear in an ultrasound or MRI. Radiation treatment can also cause edemas to occur.
  • Infection. Bone infection can cause increased water in bone. The edema will typically go away after the infection is treated.

In many cases, the liquid inside your bone will go away with time, therapy, and pain medication, such as nonsteroidal anti-inflammatory drugs (NSAIDs).

In more serious cases, surgery may be required. A common procedure for bone marrow lesions or edemas is core decompression. This involves holes being drilled into your bone. Once the holes are drilled, the surgeon may insert bone graft material or bone marrow stem cells — to fill the cavity. This stimulates normal bone marrow growth.

The detection of bone marrow edema is important, especially in managing symptoms of arthritis, stress fracture, cancer, or infection. Edema can indicate where pain started and how strong your bones are, which can affect treatment.

If you doctor tells you that you have bone marrow edema, be sure to ask the cause and their recommended treatment. Typically, your doctor will tell you that time, therapy and, if needed, pain medication will be enough to relieve your condition.