Association of perioperative thromboprophylaxis on revision rate due to infection and aseptic loosening in primary total hip arthroplasty – new evidence from the Nordic Arthroplasty Registry Association (NARA)

Thea Emily Benson; Ina Trolle Andersen; Søren Overgaard; Anne Marie Fenstad; Stein Atle Lie; Jan-Erik Gjertsen; Ove Nord Furnes; Alma Becic Pedersen

doi:10.2340/17453674.2022.2461

Authors

Thea Emily Benson Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark
Ina Trolle Andersen Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark
Søren Overgaard Copenhagen University Hospital, Bispebjerg, Department of Orthopaedic Surgery and Traumatology, and University of Copenhagen, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Copenhagen, Denmark https://orcid.org/0000-0001-6829-4787
Anne Marie Fenstad The Norwegian Arthroplasty Register, Department of Orthopedic Surgery, Haukeland University Hospital, Bergen, Norway https://orcid.org/0000-0002-6429-0153
Stein Atle Lie The Norwegian Arthroplasty Register, Department of Orthopedic Surgery, Haukeland University Hospital, Bergen, Norway; Department of Clinical Dentistry, University of Bergen, Bergen, Norway
Jan-Erik Gjertsen The Norwegian Arthroplasty Register, Department of Orthopedic Surgery, Haukeland University Hospital, Bergen, Norway; Department of Clinical Medicine, University of Bergen, Bergen, Norway https://orcid.org/0000-0002-8490-268X
Ove Nord Furnes The Norwegian Arthroplasty Register, Department of Orthopedic Surgery, Haukeland University Hospital, Bergen, Norway; Department of Clinical Medicine, University of Bergen, Bergen, Norway https://orcid.org/0000-0001-8223-2515
Alma Becic Pedersen Department of Clinical Epidemiology, Aarhus University Hospital and Department of Clinical Medicine, Aarhus University, Aarhus, Denmark https://orcid.org/0000-0002-3288-9401

DOI:

https://doi.org/10.2340/17453674.2022.2461

Keywords:

anticoagulants, Arthroplasty, Hip, LMWH, NOAC, revision, thromboprophylaxis

Abstract

Background and purpose: Results regarding the impact of anticoagulants on revision rate are conflicting. We examined the association between the use of low molecular weight heparin (LMWH) or non-vitamin K oral anticoagulants (NOACs) as thromboprophylaxis after primary total hip arthroplasty (THA) and the revision rate due to infection, aseptic loosening, and all causes.

Patients and methods: We conducted a cohort study (n = 53,605) based on prospectively collected data from the national hip arthroplasty registries from Denmark and Norway. The outcome was time to revision due to infection, aseptic loosening, and all causes, studied separately. Kaplan–Meier (KM) survival analysis and a Cox proportional hazard model was used to estimate implant survival and cause-specific hazard ratios (HRs) with 95% confidence intervals (CI) adjusting for age, sex, Charlson Comorbidity Index, fixation type, start, and duration of thromboprophylaxis, and preoperative use of Vitamin K antagonists, NOAC, aspirin, and platelet inhibitors as confounders.

Results: We included 40,451 patients in the LMWH group and 13,154 patients in the NOAC group. Regarding revision due to infection, the 1-year and 5-year KM survival was 99% in both the LMWH group and in the NOAC group. During the entire follow-up period, the adjusted HR for revision due to infection was 0.9 (CI 0.7–1.1), 1.6 (CI 1.3–2.1) for aseptic loosening, and 1.2 (CI 1.1–1.4) for all-cause revision for the NOAC compared with the LMWH group. The absolute differences in revision rates between the groups varied from 0.2% to 1%.

Interpretation: Compared with LMWH, NOACs were associated with a slightly lower revision rate due to infection, but higher revisions rates due to aseptic loosening and all-cause revision. The absolute differences between groups are small and most likely not clinically relevant. In addition, the observed associations might partly be explained by selection bias and unmeasured confounding, and should be a topic for further research.