Table 1. Risk Factors for Venous Thromboembolism
Primary hypercoagulable states
MMAntithrombin III deficiency
MMProtein C deficiency
MMProtein S deficiency
MMActivated protein C resistance
Secondary hypercoagulable states
MMBed rest or immobility longer than 5 days
MMMalignancy
MMCongestive heart failure
MMEstrogen use or hormone replacement therapy
MMFractures of pelvis, hip, or leg
MMHistory of myocardial infarction
MMHistory of stroke
MMIndwelling femoral vein catheter
MMInflammatory bowel disease
MMMajor surgery (particularly in operations involving abdomen, pelvis, and lower extremities)
MMMultiple trauma
MMObesity
MMParalysis
MMPrior venous thromboembolic disease
MMVaricose veins
MMHistory of smoking

Koval, KJ (ed): Orthopaedic Knowledge Update 7. Rosemont, IL. American Academy of Orthopaedic Surgeons. 2002 Ch. 6, pp. 55-62.