Fig. 4From: CRISTAL (a cluster-randomised, crossover, non-inferiority trial of aspirin compared to low molecular weight heparin for venous thromboembolism prophylaxis in hip or knee arthroplasty, a registry nested study): statistical analysis planBetween group change in overall 90-day symptomatic VTE rate and non-inferiority margin. The dotted line represents the non-inferiority marginBack to article page