Epidemiology
The true incidence and mortality rate of FES is unclear, mainly because
there are often concomitant injuries and pre-existing problems. Fat
embolism and milder forms of fat embolism syndrome may stay clinically
undetected. In retrospective studies the incidence of FES is less than
1%, in contrast to the incidence of 11%-29% in prospective
reviews.4-8 Differences in the diagnostic criteria and
the over-diagnosis in prospective studies and under-diagnosis in
retrospective studies are possible explanations for this varying
incidence. The incidence of fat embolism in post mortem examinations
rises up to 20%.9 It is estimated that fat embolisms
occur in more than 90% of patients with fractures of the long bones or
multiple injuries, patients undergoing intramedullary reaming and
nailing, and patients undergoing total hip arthroplasty. These estimates
are based on both postmortem findings in trauma victims as well as
prospective studies that used either transthoracic or transesophageal
echocardiography to monitor the “showering” of micro emboli through
the heart and lungs that took place during certain corrective orthopedic
procedures.10