In this report we attempt to estimate the incidence of deep vein thrombosis in patients undergoing low-complexity knee arthroscopy and explore possible indications for anti-embolic prophylaxis according to the calculated probability of deep vein thrombosis.
This is a prospective cohort study. Subjects were adult patients undergoing low-complexity knee arthroscopy between September 2001 and November 2004. Patients with a diagnosis of deep vein thrombosis before the procedure and those who were receiving anticoagulant medications were excluded. Doppler ultrasound was performed 8 and 30 days after the procedure. Multivariate logistic regression model was used to calculate the probabilities of deep vein thrombosis depending on the presence or absence of risk factors. One hundred and four patients were included.
The estimated incidence of deep vein thrombosis was 8.6% [95% confidence interval (CI) 3% to 14%]. Bivariate analysis showed an association between tourniquet duration time longer than 40 minutes and deep vein thrombosis (P=0.019). Multivariate logistic regression analysis confirmed that association (OR=14.7, 95% CI 1.4-157, P=0.02) and showed a trend towards significance for the association between hormonal therapy and deep vein thrombosis (OR=10.9, 95% CI 0.6-187, P=0.09). According to the logistic regression model, seven different clinical scenarios showed a high probability of deep vein thrombosis.
The risk of deep vein thrombosis in patients undergoing low-complexity knee arthroscopy may be high enough to justify antiembolic prophylaxis depending on the absence or presence of risk factors. Prolonged tourniquet duration time is associated with deep vein thrombosis.
Level of Evidence
Level II (prognostic study with patient enrollment at the same time in their disease process and completed follow-up for more than 80% of the patients).