Bone marrow edema syndrome is typically accompanied by severe, usually weight-bearing pain in the affected bone segment. Bone marrow edema—that is, the increased accumulation of fluid in the bone—is the hallmark of the condition.
The term “bone marrow edema syndrome” describes the entire complex of
- causes,
- pain, and
- consequences.
In principle, the condition can occur in any bone, but it most commonly affects the hip joint and, less frequently, the knee.
The first case of bone marrow edema syndrome was described by Curtiss and Kincaid in 1959. At that time, the authors reported on a woman in the third trimester of her pregnancy. She presented with a clinical syndrome characterized by hip pain and reduced bone density on X-ray.
The pain syndrome was associated with a temporary decrease in radiographic density in the corresponding bone areas. Consequently, Hunter and Kelly named the syndrome “transient osteoporosis” in 1968.
The term “bone marrow edema” was not introduced until after magnetic resonance imaging (MRI) had become established in the diagnosis of unexplained bone and joint disorders. Wilson therefore replaced the term “transient osteoporosis” with “transient bone marrow edema syndrome” in 1988.
In 1989, one year later, Turner reported that this syndrome may be associated with avascular bone necrosis. Since then, many authors have assumed the existence of a disease continuum that begins with bone marrow edema and may progress to avascular bone necrosis.
Bone marrow edema likely represents an early, reversible phase of avascular bone necrosis. This hypothesis is supported by similarities in the histological examination of the bone, which is identical for early avascular necrosis and bone marrow edema. According to the Association for Research on Circulation in Bone (ARCO), four stages can be distinguished:
- Stage I: Bone marrow edema
- Stage II: Osteonecrosis with focal osteoporosis on X-ray
- Stage III: Subchondral fracture with a crescent sign on X-ray
- Stage IV: Collapse of the cortical bone and development of osteoarthritis.
The condition is typically accompanied by severe pain in the affected bone segments. Aside from the pain, which is usually load-dependent, there are few other symptoms.
The clinical course of the disease is characterized by pain that varies with position or activity. Symptoms improve when lying down or sitting. Immobilization or rest of the limb does not lead to lasting improvement. Medications also cannot eliminate the pain in the long term.
Transient osteoporosis may be suspected if four of the following five criteria are met:
- pain triggered by physical activity
- absence of other symptoms
- no spontaneous improvement
- no clear improvement with pain medication
- Normal X-ray findings
Bone marrow edema is not visible on a standard X-ray. Only later in the course of the disease does a temporary decrease in X-ray density become apparent in the affected bone segment. A bone scan may provide evidence of transient osteoporosis.
Imaging of bones using bone scintigraphy © agenturfotografin | AdobeStock
Bone marrow edema is diagnosed almost exclusively via magnetic resonance imaging (MRI). It appears as hyperintense signal on STIR and T2-weighted images and as hypointense signal in the bone marrow on T1-weighted MR images.
The condition most commonly occurs in the hip joint and less frequently in the knee. However, like avascular bone necrosis, it can in principle occur in any bone.
The syndrome can occur in three situations:
- Impaired blood flow to the bone
- mechanical overload of the bone resulting in microfractures
- As a reactive comorbidity associated with other bone and joint diseases
The circulatory disturbance can be caused either by impaired arterial inflow or venous outflow. In biopsies, the arteries rarely show wall changes or thrombus formation. Therefore, the syndrome is likely caused more frequently by venous stasis than by an arterial interruption of blood supply. Mechanical bone marrow edema is caused by bone overload or trauma.
Reactive bone marrow edema is associated with, for example,
In summary, the following conditions and situations can trigger bone marrow necrosis:
- Blood clotting disorders (e.g., thrombophilia),
- metabolic disorders (e.g., Gaucher disease),
- blood disorders (e.g., sickle cell anemia),
- Medications (e.g., cortisone),
- Transplantation (e.g., cyclosporine),
- pregnancy,
- Sports (diving),
- Rheumatic diseases (e.g., rheumatoid arthritis),
- hormonal disorders (e.g., hypogonadism),
- complex regional pain syndrome (e.g., Sudeck’s disease),
Therapeutically, the underlying condition must be treated. Identifying the cause is therefore essential. Depending on the cause and stage of the condition, various treatment options are available.
After the onset of a fracture or osteoarthritis, joint replacement with an endoprosthesis is often the only remaining option. This procedure is performed by orthopedic surgeons. The syndrome is often not correctly diagnosed until the disease has progressed to an advanced stage. At that point, only surgical or even palliative treatment is possible.
Early detection of the disease and identification of its cause make it possible to address the various aspects of its development. This can positively influence the course of the disease.
Transient osteoporosis is
- either a self-limiting condition or
- it progresses to irreversible bone necrosis.
To date, there is no way to predict the future course of the disease in advance. In most cases, the disease lasts about one year.
What is bone marrow edema?
Bone marrow edema is an accumulation of fluid in the bone marrow or cancellous bone. BME frequently occurs following a fracture, overuse, or inflammatory changes. Typical symptoms include joint pain and load-dependent symptoms in the affected limb.
How is bone marrow edema diagnosed?
Bone marrow edema is usually diagnosed using MRI. On an MRI scan, increased signal intensity is visible in the bone marrow. In contrast, X-rays are often unremarkable, which is why additional imaging procedures are frequently necessary for diagnosis.
What treatment is effective for bone marrow edema?
Treatment for bone marrow edema primarily involves reducing stress on the affected area, immobilization, and physical therapy. In addition, analgesics, nonsteroidal anti-inflammatory drugs (NSAIDs), or infusions of iloprost to improve blood flow are used. Modern treatment methods such as shock wave therapy (ESWT) or core decompression can also be helpful.
Can bone marrow edema resolve on its own?
Many cases of bone marrow edema are self-limiting and resolve within a few months. However, it is important to initiate treatment early and relieve pressure on the affected area to prevent complications such as osteonecrosis, bone fracture, or bone death.
When is surgery necessary for bone marrow edema?
If conservative treatment methods are insufficient or there is a risk of bone necrosis, surgery may be performed. Procedures such as drilling or core decompression may be considered. The orthopedic surgeon determines the appropriate treatment based on the cause, etiology, and course of the disease.
