One hundred and ninety-five patients scheduled for a total hip or knee arthroplasty were randomized to receive post-operative aspirin twice daily for 35 days, with adherence managed by a smartphone application plus standard adherence instructions (n=96) or with standard adherence instructions only (n=99). The outcomes of interest included the AIDS Clinical Trial Group (ACTG) Adherence Questionnaire, the Aspirin General Adherence Scale, the Aspirin Self-Efficacy Scale, and the incidence of 100% adherence. Outcomes were scheduled to be assessed at 36 days and 6 weeks post-operation. No statistically significant differences in ACTG scores (p=0.54), Aspirin Self Efficacy Scale scores (p=0.328), or incidence of 100% adherence (p=0.80) were observed between the two groups at 42 days post-operation. Moreover, Aspirin General Adherence Scores were statistically significantly in favour of the smartphone application group compared to the control group (p=0.018).