Bone marrow is the spongy, soft substance located inside the bones that is responsible for new cell growth. Cells such as red blood cells, white blood cells and platelets transport oxygen and fight off infections, and are responsible for clotting to avoid heavy bleeding in case of injury. Bone marrow edema is a natural protective response of the body in a state of injury or stress. Usually, bone marrow edema means that the bone marrow contains too much fluid. Edema or inflammation caused by the presence of excess fluid in the bone marrow is only a symptom. In other words, there must be some underlying cause for the condition to occur. This is because the bone marrow changes caused by edema can be caused by a fracture or ligament injury. For example, this edema can be caused by problems such as synovitis, osteoarthritis, osteoporosis and ischemia. Bone marrow edema is sometimes associated with pain and bone and joint dysfunction. These symptoms are often related to the underlying cause of the fluid buildup. For example, movement causing mild pain may be associated with structural changes in the joint. These can be seen as symptoms of arthritis and, if severe and intense pain is present, may also be a sign of bone compression or fracture. Fluid edema or inflammation can often be understood through magnetic resonance imaging. Treatment of bone marrow edema depends on the cause of the swelling and fluid retention. Treatment of severe injury and underlying disease can help relieve symptoms of bone marrow edema pain and dysfunction. The use of analgesics and, in severe cases, steroid injections can be effective in reducing inflammation. Other cases, however, may require more invasive treatment measures. Surgical interventions can help repair damaged ligaments, promote bone healing, and remove masses that cause chronic edema and pain.