Venous Thromboembolism despite Ongoing Prophylaxis after Fast-Track Hip and Knee Arthroplasty: A Prospective Multicenter Study of 34,397 Procedures

INTRODUCTION:  Venous thromboembolism (VTE) is a serious complication to total hip and knee arthroplasty (THA/TKA). However, recent publications found low 90-day incidences of VTE with in-hospital only thromboprophylaxis after fast-track THA and TKA, but with a subgroup with VTE despite thromboprophylaxis.

OBJECTIVES:  We aimed to investigate in detail the incidence and risk for VTE despite ongoing thromboprophylaxis after fast-track THA and TKA.

MATERIALS AND METHODS:  This is a prospective unselected multicenter cohort from January 2010 to August 2017. Data on preoperative characteristics were entered into the Lundbeck Foundation Centre for Fast-track Hip and Knee Replacement database (www.FTHK.dk). Length of stay (LOS) and complete 90-day follow-up was obtained from the Danish National Patient Registry and review of medical records. Patients with preoperative use of potent anticoagulants were excluded.

RESULTS:  Of 34,397 procedures, 32 (0.09%, 22.4% of all VTE) had VTE after median 2 (interquartile range: 2-4) days despite ongoing thromboprophylaxis. Twenty-nine (2.1% of LOS > 5 days) occurred with LOS > 5 days and 3 during primary admission with LOS ≤ 5 days. Note that 78% of VTEs despite ongoing thromboprophylaxis occurred without any identifiable pre-VTE complication. Risk factors were age from 81 to 85 years (odds ratio [OR] 6.3 [95% confidence interval: 1.8-22.4], p = 0.005), body mass index (BMI) < 18.5 (OR 11.1 [1.1-109.2], p = 0.040), BMI 35 to 40 (OR 5.1 [1.0-26.2], p = 0.050), and BMI ≥ 40 (OR 21.8 [4.6-103.6], p < 0.001).

CONCLUSION:  VTE after fast-track THA/TKA occurred after median 2 days in 0.09% (22% of all VTE) despite ongoing thromboprophylaxis. Further investigation of this "high-risk" population might help to improve the optimal choice for patient-specific thromboprophylaxis to further reduce incidence of postoperative VTE.