Venous thromboembolism (VTE) prophylaxis has always been a matter of debate in moderate-risk orthopaedic procedures. To prevent or no prevent, that is the question. More than 3000 patients undergoing knee arthroscopy (n = 1543, meniscectomy, diagnostic arthroscopy, removal of loose bodies, or other indications, POT-KAST study) or cast immobilisation (n = 1519, with or without surgery before or after casting but without multiple traumatic injuries, POT-CAST study) were included in these two large parallel, pragmatic, multicentre, randomised, controlled, open-label trials with blinded outcome evaluation. The patients were assigned to receive either a prophylactic dose of low-molecular-weight heparin (for the 8 days after arthroscopy or during the full period of immobilisation due to casting) or no anticoagulant therapy. The primary outcomes were the cumulative incidences of symptomatic VTE and major bleeding within 3 months after the procedure.

The results of these two trials show that prophylaxis with low-molecular-weight heparin for the 8 days after knee arthroscopy or during the full period of immobilisation due to casting was not effective for the prevention of symptomatic VTE. In addition, no differences in bleeding incidence were observed. These results support and confirm the recommendations of the 8th and 9th editions of American College of Chest Physicians (ACCP) guidelines for this setting. They also contradict the findings of other studies using a surrogate endpoint (compression ultrasound for either asymptomatic and symptomatic events), as compared to only symptomatic events here. The pragmatic design of the POT-CAST and POT-KAST studies reinforces the strength of theses studies sticking to real life. However, it should be point out that these trials were not blinded and the very low incidence of VTE in POT-KAST can also be considered as a limitation.

– Charles Marc Samama