Etymed
osteonecrosis
Definition
Death of bone tissue due to interruption of blood supply (avascular necrosis), leading to bone collapse and joint destruction. Commonly affects the femoral head, humeral head, and femoral condyles.
Clinical context
A 35-year-old male with systemic lupus erythematosus on chronic corticosteroid therapy presents with progressive bilateral hip pain over 4 months, worse with weight-bearing. Physical examination reveals limited range of motion in both hips, particularly internal rotation. X-ray of the hips shows sclerosis and early collapse of the right femoral head (Ficat stage III). MRI confirms bilateral femoral head osteonecrosis with a characteristic "double-line sign" on T2-weighted images (inner low-signal line of necrotic bone, outer high-signal line of reactive tissue). He is referred for total hip arthroplasty of the right hip and core decompression of the left.
Mnemonic
OSTEO (bone) + NECRO (death) + OSIS (condition) = condition of bone death. Think of AVN (avascular necrosis) — no blood = bone death. Risk factors: Steroids, Sickle cell, SLE, Alcohol ("SSSA").
These morphemes also unlock…
- oste/o — bone (from osteon)
- necr/o — death; dead tissue (from nekros, corpse)
- -osis — abnormal condition