Bone & joints
Other nonneoplastic
Avascular necrosis
Author: Nat Pernick, M.D.
Last author update: 1 August 2013
Last staff update: 1 May 2023
Copyright: 2003-2023, PathologyOutlines.com, Inc.
PubMed Search: Avascular necrosis[title]
Table of Contents
Definition / general | Radiology images | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) imagesCite this page: Pernick N. Avascular necrosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/boneasepticbonenecrosis.html. Accessed May 29th, 2023.
Definition / general
- Also called avascular bone necrosis, osteonecrosis
- Common; affects almost every bone, including tibial tuberosity (Osgood-Schlatter’s disease), proximal femoral epiphysis (Legg-Calve’-Perthes disease)
- > 50% of cases are multifocal
- Causes 10% of joint replacements
- Significant cause of arthritis due to fractures through articular surface of hip, knee and other major joints; also due to collapse of necrotic bone segment with resulting reparative granulomas that destroy bone at margin of infarct, may cause detachment of cartilage and secondary degenerative joint disease
- Causes: fracture, dislocation, corticosteroids, nitrogen bubbles in dysbarism, vasculitis, radiation, vascular compression, venous hypertension, thrombosis (sickle cell disease), Gaucher’s disease, alcoholism
- Pathophysiology: initially necrosis of epiphysis, with variable necrosis of adjacent cartilage; dead bone is resorped by “creeping substitution” over months/years; new bone is soft, may flatten and cause degenerative joint disease
- Creeping substitution: dead trabeculae that are not resorbed by osteoclasts serve as scaffolds for deposition of new living bone
Radiology images
Contributed by Mark R. Wick, M.D.
Aseptic vascular necrosis femoral head Xray
Gross description
- Intact articular cartilage except at edge of necrotic area, which exhibits cracking and folding
- Necrotic area in cross section is yellow, opaque, chalky with hyperemic fibrous tissue at margin
- Adjacent bone may be thickened
- Late changes are breaks in smooth contour of femoral head, destruction of articular cartilage, loose bodies and marginal osteophytes (changes of degenerative joint disease)
Gross images
Contributed by Mark R. Wick, M.D.
Aseptic vascular necrosis femoral head
Microscopic (histologic) description
- Dead trabeculae (empty lacunae) stain deeper blue than nonnecrotic bone
- Have ragged margins with osteoclasts on one side and osteoblasts on the other
- Lacunae may be enlarged and cystic or normal size with pyknotic nuclei
- Calcium salts due to necrotic adipocytes
- Marrow has fat necrosis and calcium deposits (marrow is a more sensitive indicator of necrosis than bone)
Microscopic (histologic) images
Contributed by Mark R. Wick, M.D.
Aseptic vascular necrosis femoral head
