Association between duration of anticoagulant thromboprophylaxis and revision rate in primary total hip arthroplasty: a Danish and Norwegian nationwide cohort study

BACKGROUND AND PURPOSE: There are concerns that bleeding following primary total hip arthroplasty (THA) contributes to prolonged wound drainage and prosthetic joint infection (PJI). We examined whether short (1–5 days), medium (6–14 days), and extended (≥ 15 days) duration of thromboprophylaxis is associated with the 5-year revision rate after THA due to osteoarthritis. PATIENTS AND METHODS: We performed a cohort study based on data from hip arthroplasty and administrative registries in Denmark and Norway (2008–2014). The outcome was revision surgery due to PJI, aseptic loosening or any cause, and patient mortality. Adjusted cause-specific hazard ratios (HRs) were analyzed with Cox regression analyses. RESULTS: Among 50,482 THA patients, 8,333 received short, 17,009 received medium, and 25,140 received extended thromboprophylaxis. The HRs for revision due to PJI within 5 years were 1.0 (95%CI 0.7–1.3) and 1.1 (CI 0.9–1.3) for short and extended vs. medium treatment, whereas HR for extended vs. medium prophylaxis was 1.5 (CI 1.2–2.0) within 3 months. The HRs for revision due to aseptic loosening within 5 years were 1.0 (CI 0.7–1.4) and 1.1 (CI 0.9–1.4) for short and extended vs. medium treatment. The HRs for any revision within 5 years were 0.9 (CI 0.8–1.1) and 0.9 (CI 0.8–1.0) for short and extended vs. medium treatment. Extended vs. medium prophylaxis was associated with a decreased 0–3 month mortality. The absolute differences at 5 years were ≤ 1%. CONCLUSION: Our data suggests no association between duration of anticoagulant thromboprophylaxis and revision rate within 5 years of primary THA. The extended thromboprophylaxis might be associated with early increased revision rate due to PJI but also with lower mortality; however, the clinical relevance of this finding requires further research.