Summary
A high incidence of post-discharge venous thromboembolism in orthopaedic surgery patients
has been recently reported drawing further attention to the unresolved issue of the
optimal duration of the pharmacological prophylaxis. We performed an overview analysis
in order to evaluate the incidence of late occurring clinically overt venous thromboembolism
in major orthopaedic surgery patients discharged from the hospital with a negative
venography and without further pharmacological prophylaxis. We selected the studies
published from January 1974 to December 1995 on the prophylaxis of venous thromboembolism
after major orthopaedic surgery fulfilling the following criteria: 1) adoption of
pharmacological prophylaxis, 2) performing of a bilateral venography before discharge,
3) interruption of pharmacological prophylaxis at discharge in patients with negative
venography, and 4) post-discharge follow-up of the patients for at least four weeks.
Out of 31 identified studies, 13 fulfilled the overview criteria. The total number
of evaluated patients was 4120. An adequate venography was obtained in 3469 patients
(84.1%). In the 2361 patients with negative venography (68.1%), 30 episodes of symptomatic
venous thromboembolism after hospital discharge were reported with a resulting cumulative
incidence of 1.27% (95% C.I. 0.82-1.72) and a weighted mean incidence of 1.52% (95%
C.I. 1.05-1.95). Six cases of pulmonary embolism were reported. Our overview showed
a low incidence of clinically overt venous thromboembolism at follow-up in major orthopaedic
surgery patients discharged with negative venography. Extending pharmacological prophylaxis
in these patients does not appear to be justified. Venous thrombi leading to hospital
re-admission are likely to be present but asymptomatic at the time of discharge. Future
research should be directed toward improving the accuracy of non invasive diagnostic
methods in order to replace venography in the screening of asymptomatic post-operative
deep vein thrombosis.
