Fat embolism, intravascular coagulation, and osteonecrosis

Area of Science:

• Orthopedics
• Pathology
• Vascular Biology

Background:

• Osteonecrosis is a significant clinical challenge.
• Understanding its early pathogenesis is crucial for effective treatment.
• Previous studies have not fully elucidated the initial pathological events.

Observation:

• Pathological specimens revealed a triad of intraosseous fat embolism, intravascular coagulation (thrombosis and hemorrhage), and osteonecrosis.
• Evaluated earliest reported nontraumatic (18 hours) and traumatic (29 hours) femoral head lesions.
• Confirmed cause and early pathogenesis in a third case.

Findings:

• Absolute overload of subchondral fat emboli, hypercoagulability, and endothelial damage trigger intravascular coagulation.
• Progressive fibrin platelet thromboses in subchondral capillaries cause osteonecrosis, exacerbated by vasoconstriction and impaired fibrinolysis.
• Relative overload of fat emboli below the coagulation threshold may cause osteopenia.

Implications:

• This study provides novel insights into the early pathogenesis of osteonecrosis.
• Identifies a critical pathway involving fat embolism and coagulation.
• Suggests potential targets for therapeutic interventions to prevent bone death.