To the Editor.—
I read the interesting article, "Thromboembolism After Total Hip Reconstruction," (225:515, 1973). The authors are to be congratulated for pointing out the magnitude of the problem of venous thrombosis and pulmonary embolism following total hip replacement.However, since there were no controls in this study, the evaluation of the effectiveness of low-dose heparin for prevention of venous thrombosis is impossible. These same authors, in an excellent article, compared patients receiving low-molecular weight dextran with control patients. The incidence of deep venous thrombosis was 53.6% in the control group. Although not strictly comparable, it would seem the more recent article does suggest that low-dose heparin may reduce the incidence of venous thrombosis (ie, 53% vs 28%).I was astonished by the suggestion of the authors that perhaps low-dose heparin therapy increases the incidence of pulmonary embolization. In their article they indicated an incidence of pulmonary emboli of 24%.