Giving patients heparin before arthroscopic knee surgery or casting was not associated with lowered incidence of venous thromboembolism (VTE,) according to a Dutch study.

The POT-KAST study cohort was randomized to low-molecular weight heparin (nadroparin [Fraxiparine] or dalteparin [Fragmin] once daily for 8 days after knee surgery) or no anticoagulant. The non-blinded trial was conducted at 10 centers in the Netherlands and included 1,543 patients who underwent knee arthroscopy from 2012 to 2016.

On intention-to-treat analysis, symptomatic venous thromboembolism — either deep-vein thrombosis or pulmonary embolism — occurred in 0.7% of the heparin group, a similar figure to the 0.4% rate observed among the controls (RR 1.6, 95% CI 0.4-6.8), Suzanne C. Cannegieter, MD, PhD, of Leiden University Medical Center in the Netherlands, and colleagues reported online in the New England Journal of Medicine.

Major bleeding rates were an identical 0.1% for both (RR 1.0, 95% CI 0.1-15.7), and no patients died over the 3-month follow-up period.

POT-CAST, a parallel study by Cannegieter’s group, also found that nadroparin and dalteparin failed to lower venous thromboembolism rates — this time among those who got a lower-leg cast.