The Risk of Venous Thromboembolism is Not Equal for all Patients Who Undergo Total Joint Replacement

Abstract

Venous thromboembolism (VTE) is a well-recognized potential complication of several forms of orthopedic surgery. The current guidelines suggest extended use of VTE pharmacological prophylaxis for patients who undergo either total hip arthroplasty (THA) or total knee arthroplasty (TKA). However, the selection of an optimal prophylactic agent, risk stratification, and duration of the at-risk period remain poorly defined. Researchers have tried to adapt multiple assessment tools to bridge this gap. Krauss et al propose the use of the Caprini risk score in the postarthroplasty population. Moreover, Cronin et al complement this publication with concise guidelines for scoring that facilitates the implementation of proper VTE prophylaxis strategies. Ideally, a risk stratification methodology should be easy to implement, be capable to reliably discriminate patients with the highest risk of the development of postoperative VTE, and translate to the VTE risk reduction when used to define the optimal prophylaxis approach. To this end, the Caprini risk score has been extensively validated in surgical patients. In a meta-analysis of 14 776 patients by Pannucci et al, patients with a Caprini risk score > 8 had a significant reduction in thrombosis if they received prophylaxis (odds ratio: 0.41, 95% confidence interval: 0.26-0.65); conversely in patients with a score of less than 6 (75% of the total study population), chemoprophylaxis was not effective. This raises the question as to whether sole use of aspirin for lower risk patients is adequate; indeed the incidence of VTE at 90 days was only 0.64% among the patients randomized to aspirin in a recent randomized controlled trial among patients who underwent THA or TKA. However, all patients (n 1⁄4 3424) in this study received 10 mg of rivaroxaban for the first 5 days and 1.29% developed clinically important bleeding. There was no stratified analysis by VTE risk and risk groups were systematically excluded. In the current edition of The Journal, the idea of personalization of prophylaxis is studied in 1078 patients who underwent THA, THA revision, or TKA. Patients had their VTE risk quantified on the date of surgery. Patients with low risk received 6 weeks of aspirin 325 mg twice daily. The patients with a high risk score and who underwent THA or THA revision received 35 days of prophylactic rivaroxaban or apixaban, whereas those who underwent TKA or TKA revision were prescribed 2 weeks of direct oral anticoagulant followed by aspirin. The authors classified risk using an abbreviated, internally adopted, list of characteristics including: thrombophilia, prior VTE, malignancy, staged surgery, and morbid obesity. Key variables to derive the Caprini score were prospectively collected, which allowed the authors to retrospectively reclassify the entire group with Caprini scores according to the figure in the completion guidelines paper. The performance of the Caprini score in the postarthroplasty population was compared to the department-established guidelines. The key results were