Introduction
Bone Marrow Edema Syndrome (BMES) or Transient Osteoporosis is a temporary disease of the bones, in most cases the hip. However, knees and upper ankle joints can also be affected, although less frequently. A spontaneous pain in the hip is the classic leading symptom of this disease.
Statistically, men are affected much more frequently than women. In both sexes, the disease usually occurs in middle age, i.e. between the 3rd and 5th decade of life. A diagnosis can be made very reliably on the basis of the symptoms and by means of MRI.
Causes
The causes of the primary bone marrow edema syndrome are still unclear today, which is called “idiopathic” in the technical jargon. However, it can occur as a secondary consequence of other diseases. Traumatic injuries, such as a contusion, play a direct role here or can lead indirectly to tissue loss and ultimately to a CMO via circulatory disorders. Even in the last trimester of a pregnancy, MOCT can rarely occur due to compression fractures of the lumbar spine.
Diagnosis
X-ray examinations are usually inconspicuous in primary bone marrow edema syndrome, since a reduction in bone density is only visible after a loss of 40% of the usual bone substance. Only sometimes, but usually not until one to two months after the onset of symptoms, is a heart-shaped (focal) decrease in density visible. The secondary CMOS, on the other hand, can show characteristic changes of the underlying disease on X-ray.
The inflammation and rheumatic values remain negative in blood tests for both forms. The best way to diagnose bone marrow edema with almost 100% certainty is by MRI and to distinguish it from other diseases. This shows clear bone marrow edema, i.e. the increased accumulation of tissue fluid, especially in the femoral head and neck.
This can also be the case in deeper regions of the femur and can be a blurred area. This image is typical for a CME. A scintigraphy can also be useful in making a diagnosis.
By using radioactive markers, a characteristically increased blood circulation of the hip and an increased activity of the bone-forming cells becomes visible. The most important differential diagnosis is osteonecrosis. This is the death of bone substance as a result of an infarction (the occlusion of a vessel). With the above-mentioned examination findings, however, osteonecrosis can be distinguished very well from CMSO.
