Abstract
1. The gravity of thrombo-embolic complications in orthopaedic and accident surgery has stimulated us, since 1951, to devise a means of prevention which comprises: a) the use of anticoagulants, the mode of administration of which has been determined by an experience of over 5,000 cases; and b) a method of selecting those patients most threatened by thromboembolism. 2. Although there could be no absolute guarantee of protection, these measures offered a considerable reduction in the risk of thrombotic complications.