Avascular necrosis: etiology in one word

Avascular necrosis (AVN) is defined as cellular death of bone components due to interruption of the blood supply; the bone structures then collapse, resulting in bone destruction, pain, and loss of joint function.



PLASTIC (Mnemonic for etiologies of AVN):

• P: Pregnancy/Pancreatitis
• L: Lupus, Sickle cell anemia
• A: Alcohol
• S: Steroids, Septic arthritis
• T: Trauma, includes Radiation therapy
• I: Idiopathic eg. Legg-Calve-Perthes disease
• C: Caissons

FICAT Classification

* Stage I: Radiographs are normal (MRI or radionuclide imaging findings will confirm AVN).

* Stage II: Cystic and sclerotic changes are seen on radiographs.

* Stage III: Crescent sign is present.

* Stage IV: Flattening of the femoral head, narrowing of the hip joint, and, ultimately, severe joint destruction.