Postoperative thromboprophylaxis does not reduce the incidence of thromboembolic events after ACL reconstruction

Anterior cruciate ligament (ACL) reconstructive surgery is one of the most common ligament-related surgeries performed in France. The French Society of Anesthesia & Intensive Care Medicine (SFAR) recommends the systematic use of low-molecular weight heparin postoperatively to prevent venous thromboembolisms (VTE). However, these recommendations differ from one country to another; several national societies do not recommend them. To specify the benefits of such a treatment, we did a retrospective case-control study to evaluate the incidence of symptomatic VTE after ACL reconstruction. Hypothesis We hypothesized that the rate of symptomatic VTE would be the same, whether a course of postoperative anticoagulants is prescribed or not.

This was a retrospective, multicenter, multi-surgeon study. Of the four participating surgeons, two never prescribed thromboprophylaxis after surgery while the other two always prescribed a 10-day course of low-molecular weight heparin. All patients who underwent primary ACL reconstruction using an autologous graft between the 1st of January 2019 and the 15th of February 2020 were included. The 535 patients who had undergone ACL reconstruction were divided into two groups: (Group 1) 279 patients in the group without anticoagulants; 96% received a four-strand semi-tendinosus graft (ST4) and 4% received a quadriceps tendon (QT) graft; the mean age of these patients was 30 years (14-58); 41% of them were women and 22% of them were smokers; the mean body mass index was 24.4 (18-37); the mean tourniquet time was 37minutes. (Group 2) 256 patients in the group with anticoagulants; 81% received a semi-tendinosus/gracilis graft, 15% received a ST4 and 4% a QT; the mean age of these patients was 29 years (14-60); 38% of them were women and 21% of them were smokers; the mean body mass index was 25.0 (18-38); the mean tourniquet time was 34minutes. The two groups were comparable in all respects except for the type of graft used. All patients were contacted at a minimum interval of 3 months after their surgery, by telephone. Doppler ultrasonography was done solely when a VTE was suspected.

In the group without anticoagulants, 249 of 279 patients were contacted, while in the group with anticoagulants, 221 of 256 were contacted. The two groups were comparable in terms of age, gender ratio, tourniquet time, body mass index and proportion of smokers. Two cases of deep vein thrombosis (all in the calf region) were found in each group with no associated pulmonary embolism. There was no difference between groups in the VTE rate.

Our hypothesis was confirmed since the incidence of symptomatic VTE was the same whether postoperative anticoagulants were prescribed or not. The incidence of symptomatic VTE after ACL reconstruction was identical whether thromboprophylaxis was used or not. This casts doubt on the need for postoperative thromboprophylaxis, especially in younger patients who do not have risk factors, and brings into question whether the recommendations in France should be changed.

III (retrospective case-control study).