SCREENING FOR DEEP VENOUS THROMBOSIS IN ASYMPTOMATIC POSTOPERATIVE ORTHOPEDIC PATIENTS USING COLOR DOPPLER SONOGRAPHY - ANALYSIS OF PREVALENCE AND RISK-FACTORS

OBJECTIVE. The purpose of our study was to assess the prevalence and r isk factors for sonographically detectable lower extremity deep venous thrombosis (DVT) in asymptomatic patients following major orthopedic surgery. SUBJECTS AND METHODS. We performed color Doppler sonography o f the lower extremities in 474 asymptomatic patients following major h ip or knee surgery, We determined the prevalence of lower extremity DV T and used stepwise logistic regression to identify factors predictive of DVT, All patients received routine prophylactic measures. RESULTS. The prevalence of DVT was 7%. Laterality of surgery, age, and gender were all independent predictors of DVT (p less than or equal to.01): t he odds of having DVT were 20 times higher in the leg that was operate d upon than in the leg that was not; the odds of DVT rose by a factor of 1.5 per decade of life; and the odds of DVT were 3.4 times greater in men than in women. DVT was more common in patients who had received general rather than epidural anesthesia, with borderline significance (p=.06). The length of anesthesia and the joint involved (hip or knee ) were not predictive of DVT (p>.10). CONCLUSION. Despite prophylaxis, DVT is a relatively common postoperative complication in patients who undergo major orthopedic procedures. Routine screening for DVT is war ranted in asymptomatic patients who have undergone hip or knee surgery , and color Doppler sonography, despite its limitations, offers a reas onably accurate noninvasive method for screening these patients. Subse ts of patients who are at particular risk include the elderly, male pa tients, and patients who have undergone general anesthesia. The low pr evalence of DVT in limbs not operated upon suggests that routine scree ning may be limited to evaluating the affected limbs only, thus helpin g to minimize the cost of screening.