Avn

Avascular Necrosis
Synonyms	Osteonecrosis, Aseptic Necrosis, Ischemic Bone Necrosis
Pronounce	N/A
Specialty	N/A
Symptoms	Joint pain, limited range of motion
Complications	Joint collapse, arthritis
Onset	Gradual
Duration	Long-term
Types	N/A
Causes	Reduced blood flow to bone
Risks	Trauma, steroid use, alcoholism
Diagnosis	MRI, X-ray, CT scan
Differential diagnosis	N/A
Prevention	N/A
Treatment	Medication, physical therapy, surgery
Medication	N/A
Prognosis	Variable
Frequency
Deaths	N/A

Avascular Necrosis (AVN), also known as Osteonecrosis, Aseptic Necrosis, or Ischemic Bone Necrosis, is a condition that occurs when there is loss of blood to the bone. Since bone is a living tissue that requires blood, an interruption to the blood supply causes the bone to die. If not stopped, this process eventually causes the bone to collapse.

Pathophysiology

Avascular necrosis occurs when blood flow to a section of bone is interrupted. This can be due to a variety of factors, including trauma, which can damage blood vessels, or non-traumatic causes such as steroid use, excessive alcohol consumption, or certain medical conditions like sickle cell disease. The lack of blood flow leads to the death of bone tissue, and over time, the bone can collapse.

Causes

The causes of avascular necrosis can be broadly categorized into traumatic and non-traumatic causes:

Traumatic Causes

• Fractures or dislocations that damage the blood vessels supplying the bone.

Non-Traumatic Causes

• Long-term use of high-dose corticosteroids.
• Excessive alcohol consumption.
• Medical conditions such as sickle cell disease, lupus, and Gaucher's disease.
• Certain medical treatments, such as radiation therapy.

Symptoms

The most common symptom of avascular necrosis is pain in the affected joint. The pain may be mild at first and increase gradually over time. As the condition progresses, the joint may become stiff and lose its range of motion. In advanced stages, the bone and surrounding joint may collapse, leading to severe pain and disability.

Diagnosis

Diagnosis of avascular necrosis typically involves imaging studies:

• X-ray: May show changes in bone structure in advanced stages.
• MRI: The most sensitive test for early detection of avascular necrosis.
• CT scan: Can provide detailed images of bone structure.

Treatment

Treatment for avascular necrosis aims to improve the patient's condition and prevent further bone damage. Options include:

Non-Surgical Treatments

• Medications: Nonsteroidal anti-inflammatory drugs (NSAIDs) to relieve pain.
• Physical therapy: To improve range of motion and strengthen muscles around the joint.
• Electrical stimulation: To promote bone growth.

Surgical Treatments

• Core decompression: Removing part of the inner layer of bone to reduce pressure and allow new blood vessels to form.
• Bone graft: Transplanting healthy bone tissue to the affected area.
• Joint replacement: In severe cases, replacing the damaged joint with an artificial one.

Prognosis

The prognosis for avascular necrosis depends on the stage at which it is diagnosed and the effectiveness of the treatment. Early diagnosis and treatment can improve outcomes and prevent joint collapse. However, if left untreated, avascular necrosis can lead to severe arthritis and disability.

Prevention

Preventive measures include:

• Limiting alcohol intake.
• Avoiding high-dose corticosteroids unless absolutely necessary.
• Managing underlying health conditions effectively.

See Also

• Bone fracture
• Arthritis
• Joint replacement