Objectives: To assess I he incidence and risk factors for fat embolism syndrome. Materials and Methods: Data from the National Hospital Discharge Survey (NHDS) were analyzed using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD9-CM) codes. Results: From 1979 through 2005 among 928,324,000 patients discharged from short-stay hospitals in the United States, 41,000 (0.0041%) had fat embolism syndrome. Among 21,538,000 patients with an isolated fracture of the femur (any site), tibia, fibula, pelvis, ribs, humerus, radius, or ulna, 25,000 (0.121%) developed fat embolism syndrome. Patients with multiple fractures of the femur (excluding neck) more often had fat embolism syndrome than those with isolated fractures (1.29% versus 0.541%). The incidence of fat embolism syndrome was lower with isolated fractures of the tibia or fibula (0.30%) and even lower with isolated fractures of the neck of the femur (0.06%). The incidence of fat embolism was too low to calculate with isolated fractures of the pelvis, ribs, humerus, radius, or ulna. Nonorthopedic conditions rarely, if ever, were accompanied by fat embolism syndrome. The fat embolism syndrome was more frequent in men (relative risk 5.71). Children, aged 0 to 9 years rarely had fat embolism syndrome. The fat embolism syndrome most commonly affected patients aged 10 to 39 years. Conclusions: The incidence of the fat embolism syndrome depends on the bone involved, whether fractures are isolated or multiple, the age of the patient and the gender. It rarely occurs as a result of medical conditions.
