Ankle Bone Marrow Edema and Avascular Necrosis Treatment and Surgery

What Are Ankle Bone Marrow Edema (BME) and Avascular Necrosis (AVN)?

• Bone Marrow Edema (BME): Rather than being a diagnosis on its own, this is a finding detected on MRI. It refers to an abnormal accumulation of fluid within the spongy inner spaces of the bone (bone marrow). This increase in fluid indicates that the bone is undergoing some form of stress or reaction. Bone marrow edema can occur due to many different causes:
  
  • Trauma (bone bruise, occult fracture)
  • Stress fracture
  • Overuse or excessive loading
  • Infection
  • Tumor
  • Rheumatologic diseases
  • Early stage of Avascular Necrosis
  • Transient Bone Marrow Edema Syndrome: A condition of unknown exact cause, usually seen in middle-aged men (occasionally in women in the last trimester of pregnancy), characterized by sudden-onset pain in the ankle or foot and widespread bone marrow edema on MRI, which most often resolves on its own. It is sometimes also called “transient osteoporosis.”
• Avascular Necrosis of the Talus: This is the death of bone tissue resulting from impaired blood supply to the talus bone, one of the main bones of the ankle joint. Because the talus receives most of its blood supply from a single source, it is particularly vulnerable to Avascular Necrosis. Over time, the dead bone tissue weakens and can collapse. Collapse of the talus disrupts the congruity of the ankle joint and leads to severe pain and ankle osteoarthritis.
• Relationship: In the early stages of Avascular Necrosis, bone marrow edema may be seen on MRI as the bone tissue begins to die. In other words, Avascular Necrosis can be one of the causes of bone marrow edema. However, not every case of bone marrow edema seen on MRI means Avascular Necrosis. Making the correct differential diagnosis is vital for the treatment plan.

Goal of Treatment: To relieve pain, treat the underlying problem causing the bone marrow edema (if any), prevent bone collapse in cases of Avascular Necrosis to protect the joint, or restore joint function in advanced stages.

Causes and Risk Factors

• Bone Marrow Edema Syndrome: The exact cause is unknown (idiopathic), but it is thought to be related to transient vascular changes. Risk factors are not clear.
• Avascular Necrosis of the Talus:
  
  • Trauma (over 50%): The most common cause. The blood vessels of the talus can be damaged particularly after talar neck fractures or ankle dislocations. The type of fracture and the degree of displacement affect the risk.
  • Non-Traumatic Causes: Risk factors known to cause Avascular Necrosis in the hip (long-term/high-dose corticosteroid use, excessive alcohol consumption, sickle cell anemia, SLE, clotting disorders, etc.) also increase the risk of Avascular Necrosis in the talus.
  • Idiopathic: Sometimes no clear cause can be identified.

Symptoms and Staging (for Avascular Necrosis)

The initial symptoms of both conditions can be similar:

• Pain: Usually felt deep in the ankle, with an insidious or sudden onset. It particularly increases with weight-bearing (walking, standing). Pain may also occur at rest and at night.
• Swelling: Mild swelling around the ankle.
• Limping: Difficulty walking and limping due to pain.
• Restricted Movement: Ankle movements may be restricted due to pain.

Staging of Avascular Necrosis: One of the most important factors guiding treatment is the stage of Avascular Necrosis. Staging is based on MRI and X-ray findings:

• Stage I (Pre-Collapse): X-rays may be normal or show mild bone thinning. MRI reveals bone marrow edema and the area of necrosis. The shape of the talar dome is normal. The chance of successful joint-preserving treatment is highest.
• Stage II (Pre-Collapse): X-rays show increased bone density (sclerosis) or cystic changes. The area of necrosis is evident on MRI. However, the shape of the talar dome is still preserved. Joint-preserving treatment can be attempted.
• Stage III (Early Collapse): X-rays may show a crescent-shaped fracture line beneath the talar dome (the “crescent sign”) or slight flattening of the dome. MRI confirms collapse. The joint space is usually normal. The chance of successful joint-preserving treatment is low.
• Stage IV (Advanced Collapse and Osteoarthritis): The talar dome has collapsed significantly and joint congruity is disrupted. The joint space is narrowed, and osteoarthritis (secondary arthrosis) has also developed on the opposing tibial surface. Joint-preserving treatment is no longer possible; ankle fusion or replacement is generally required.

Diagnostic Methods: How Is the Differential Diagnosis Made?

Accurate diagnosis is critical, particularly for distinguishing Bone Marrow Edema Syndrome from early-stage Avascular Necrosis.

• Detailed History: The onset and character of the pain, history of trauma, and the presence of risk factors for Avascular Necrosis (corticosteroids, alcohol, etc.) are always assessed.
• Physical Examination: The location of tenderness, joint range of motion, swelling, and gait pattern are evaluated. Findings are usually non-specific.
• Imaging Methods:
  
  • X-ray: The first step. It may reveal a fracture, advanced-stage Avascular Necrosis (collapse, osteoarthritis), or other bony problems. However, it can be completely normal in early-stage Avascular Necrosis and Bone Marrow Edema Syndrome.
  • Magnetic Resonance Imaging (MRI): The most valuable method for diagnosis and differential diagnosis.
    
    • Shows bone marrow edema very clearly.
    • Can detect Avascular Necrosis even at a very early stage (specific necrosis findings).
    • Shows the size and location of the necrosis.
    • Best assesses whether collapse of the talar dome has occurred.
    • Stages the disease.
    • Rules out other possible causes such as stress fracture, occult fracture, or tendinitis.
  • Bone Scintigraphy: Can show blood-supply changes early, but does not provide as much detail as MRI and is not specific.
  • Computed Tomography (CT): Can be used to detail bone structure, the degree of collapse, or surgical planning.

Treatment Options (Based on Diagnosis and Stage)

The treatment plan differs entirely depending on the diagnosis (Transient Bone Marrow Edema Syndrome or Avascular Necrosis?) and, if Avascular Necrosis, on the stage of the disease.

Treatment of Transient Bone Marrow Edema Syndrome:

• This condition is usually self-limiting, and treatment is supportive.
• Protective Weight-Bearing: The most important treatment step. Until the bone marrow edema resolves and the pain subsides (this can take weeks or months), it is necessary to use crutches or a special walking boot to avoid bearing weight on the ankle, or bear as little weight as possible.
• Pain Control: NSAIDs or simple pain relievers.
• Physical Therapy: Started after pain decreases, to maintain joint range of motion and regain muscle strength.
• Bisphosphonates: Some studies suggest these may help reduce pain and increase bone density, but they are not used routinely.

Treatment of Talar Avascular Necrosis:

Treatment aims to halt progression of the disease and prevent joint collapse. Options vary by stage:

• Non-Surgical Treatment: Considered only for very small, asymptomatic lesions or in patients unsuitable for surgery. Protective weight-bearing may slow progression but usually does not stop it.
• Joint-Preserving Surgery (Pre-Collapse Stages – Stage I and II):
  
  • Core Decompression: The most commonly performed joint-preserving method. Channels are drilled into the necrotic area to reduce pressure and increase blood flow. It is usually performed as a minimally invasive procedure.
  • Core Decompression + Grafting / Biological Augmentation: To increase the effectiveness of decompression, bone grafts (autograft/allograft) or cell-based therapies (BMAC, MSC – efficacy still being studied) can be added to the drilled channels. Vascularized bone grafts are more complex options.
• Salvage Surgery (Post-Collapse Stages – Stage III and IV): When joint preservation is no longer possible, the goal is to relieve pain and restore function:
  
  • Ankle Arthrodesis (Fusion): Surgical fusion of the ankle joint (between the tibia and talus), making it completely immobile. Very effective at relieving pain, but it eliminates ankle motion. It may be preferred in young, active patients or when other treatments have failed.
  • Total Ankle Replacement (TAR): Replacement of the ankle joint surfaces with metal and plastic prosthetic components. Preserves motion and relieves pain. More suitable for older patients with lower activity levels who wish to preserve joint motion. Its long-term durability and the need for revision are still greater than those of hip/knee replacements.
  • Talar Prosthesis: In very rare cases, complete removal of the talus and replacement with a custom, 3D-printed prosthesis is being applied experimentally.

Prof. Dr. Murat Bozkurt determines the most suitable treatment option (joint-preserving surgery or salvage surgery) based on the stage of ankle Avascular Necrosis and assists his patients in Ankara accordingly.

Risks, Benefits, and Recovery Process

• Benefits: The goal of treating Bone Marrow Edema Syndrome is complete resolution of symptoms. In Avascular Necrosis, the goal of joint-preserving surgery is to prevent collapse and osteoarthritis. Fusion or replacement surgeries are highly effective at relieving pain in advanced stages.
• Risks:
  
  • Core Decompression: Infection, nerve injury, fracture, failure of the procedure with progression of the disease and development of collapse, and the eventual need for ankle fusion or replacement.
  • Ankle Arthrodesis (Fusion): Infection, nerve injury, nonunion, malunion, and the development of osteoarthritis over time in adjacent joints (subtalar, midfoot).
  • Total Ankle Replacement (TAR): Infection, wound healing problems, implant loosening, wear or fracture, nerve injury, and the need for revision surgery.
• Recovery Process:
  
  • Bone Marrow Edema Syndrome (Conservative): Recovery can take months (3-12 months), and protective weight-bearing (crutches/boot) is very important during this period.
  • After Core Decompression: To protect the talus, weight-bearing must be avoided for a long period (usually at least 6-8 weeks, sometimes longer). Intensive physical therapy then begins.
  • After Ankle Fusion or Replacement: These are major surgeries. They usually require immobilization with a cast or boot after surgery and a long period of non-weight-bearing (especially after fusion surgery). Comprehensive physical therapy continues for months. Full recovery ranges from 6 months to 1 year.

Ankle Bone Marrow Edema and Avascular Necrosis Treatment in Ankara: Prof. Dr. Murat Bozkurt’s Approach

Conditions such as Bone Marrow Edema Syndrome and Avascular Necrosis should be kept in mind in the differential diagnosis of persistent ankle pain, and a specialist evaluation should be performed. In Prof. Dr. Murat Bozkurt’s approach to such conditions in Ankara:

• Accurate Diagnosis and Staging with MRI: He makes effective use of MRI to clarify the cause of ankle pain, distinguish Bone Marrow Edema from Avascular Necrosis, and correctly determine the stage if Avascular Necrosis is present.
• Staging the Treatment Plan: For Transient Bone Marrow Edema Syndrome, he recommends supportive treatment and patient follow-up; in Avascular Necrosis, he prioritizes joint-preserving surgery (core decompression +/- grafting) in the early stages (pre-collapse). In advanced stages (post-collapse), he performs salvage surgeries such as ankle fusion (arthrodesis) or total ankle replacement (TAR) depending on the patient’s age, activity level, and expectations.
• Importance of Early Intervention: He emphasizes that, particularly in Avascular Necrosis, intervention performed before collapse occurs increases the chance of preserving the joint.