Incidence of aspirin resistance in high‐risk patients following elective total hip and knee arthroplasty

Aspirin resistance (AR) is linked to increased morbidity and mortality after cardiovascular and neurovascular procedures but has not been investigated after total hip arthroplasty (THA) and total knee arthroplasty (TKA). To investigate the incidence of AR in high-risk patients after elective THA/TKA, we conducted a prospective cohort study of elective THA/TKA in patients with thromboembolic risk factors: obesity (body mass index [BMI] ≥30 kg/m²), diabetes and/or advanced age (≥65 years) who were administered aspirin for venous thromboembolism prophylaxis. AR was confirmed using a platelet function analyser. Forty patients were included with a mean±standard deviation age of 66.1±10.4 years and BMI of 32.2±6.0 kg/m² and eight (20.0%) had diabetes. Overall, 52.5% of patients were aspirin resistant, with no statistically significant relationships between patient variables and AR (P > 0.05). AR after THA/TKA was an observed phenomenon; however, larger trials are required to determine the clinical consequences of AR and to guide prophylaxis strategies in this population.