PROphylaxis in NON-Major Orthopedic Surgery - PRONOMOS

Contribution To Literature:

The PRONOMOS trial showed that rivaroxaban was superior to enoxaparin at preventing VTE.


The goal of the trial was to evaluate rivaroxaban compared with enoxaparin among patients immobilized after lower-limb nonmajor orthopedic surgery.

Study Design

  • Randomized
  • Parallel
  • Blinded
  • Stratified

Patients immobilized after nonmajor orthopedic surgery were randomized to rivaroxaban 10 mg daily/enoxaparin placebo (n = 1,809) versus enoxaparin 4000 IU subcutaneous daily/rivaroxaban placebo (n = 1,795).

  • Total number of enrollees: 3,604
  • Mean patient age: 41 years
  • Percentage female: 34%

Inclusion criteria:

  • Adults undergoing nonmajor orthopedic surgery of the lower limbs and requiring thromboprophylaxis for >2 weeks

Other salient features/characteristics:

  • Intended treatment duration: 2 weeks to 1 month in 60%, >1 month to 2 months in 37%, and >2 months in 3%

Principal Findings:

The study was terminated early on April 2018 due to slow enrollment.

The primary efficacy outcome of major venous thromboembolism (VTE), defined as symptomatic distal or proximal deep vein thrombosis (DVT), pulmonary embolism, or VTE-related death during the treatment period, or asymptomatic proximal DVT at the end of treatment, occurred in 0.2% of the rivaroxaban group compared with 1.1% of the enoxaparin group (p = 0.01).

The primary safety outcome of major and clinically relevant nonmajor bleeding occurred in 1.1% of the rivaroxaban group compared with 1.0% of the enoxaparin group (p = 0.62).

Secondary outcomes:

  • Net clinical benefit: 0.8% of the rivaroxaban group compared with 1.8% of the enoxaparin group (p < 0.05)


Among patients immobilized after nonmajor orthopedic surgery, rivaroxaban compared with enoxaparin was associated with a reduction in major VTE. Major bleeding was similar between treatment groups. Most patients received rivaroxaban from 2 weeks to 1 month. Rivaroxaban may represent an alternative to enoxaparin among patients at risk for major VTE after nonmajor orthopedic surgery.


Samama CM, Laporte S, Rosencher N, et al., on behalf of the PRONOMOS Investigators. Rivaroxaban or Enoxaparin in Nonmajor Orthopedic Surgery. N Engl J Med 2020;Mar 29:[Epub ahead of print].

Presented by Dr. Nadia Rosencher at the American College of Cardiology Virtual Annual Scientific Session Together With World Congress of Cardiology (ACC 2020/WCC), March 29, 2020.

Clinical Topics: Anticoagulation Management, Prevention, Pulmonary Hypertension and Venous Thromboembolism, Vascular Medicine, Anticoagulation Management and Venothromboembolism

Keywords: acc20, ACC Annual Scientific Session, Anticoagulants, Enoxaparin, Hemorrhage, Orthopedic Procedures, Elective Surgical Procedures, Pulmonary Embolism, Secondary Prevention, Vascular Diseases, Venous Thromboembolism, Venous Thrombosis

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