Best Orthopedic Hospital in Nagpur

Avascular Necrosis (AVN) can be classified in a few different ways depending on cause, location, and pattern of bone involvement. Here are the main types of AVN:

🔹 1. Based on Cause (Etiology)

Traumatic AVN

• Occurs after injury (fracture or dislocation)

• Blood supply to bone is directly disrupted

• Common in femoral neck fractures, hip dislocations

Non-Traumatic AVN

• No direct injury

• Caused by conditions like:

  • Steroid use

  • Alcohol abuse

  • Sickle cell disease

  • Autoimmune disorders

🔹 2. Based on Number of Bones Involved

Unifocal AVN

• Involves a single bone (most common: femoral head)

Multifocal AVN

• Involves multiple bones (≥3 sites)

• Often associated with systemic diseases or long-term steroid use

🔹 3. Based on Location (Common Sites)

• Hip (Femoral Head AVN) – most common

• Knee (Femoral condyle AVN)

• Shoulder (Humeral head AVN)

• Ankle (Talus AVN)

• Wrist (Lunate – Kienböck’s disease)

🔹 4. Special Types

Legg-Calvé-Perthes Disease

• AVN of femoral head in children

Kienböck’s Disease

• AVN of lunate bone in wrist

Spontaneous Osteonecrosis of Knee (SONK)

• Sudden onset knee AVN, usually in older adults

🔹 5. Based on Radiological/Clinical Staging (Ficat & Arlet)

• Stage I – Normal X-ray, MRI changes

• Stage II – Sclerosis/cysts visible

• Stage III – Subchondral collapse (crescent sign)

• Stage IV -Joint destruction & arthritis