INTRODUCTION: The aim of this study was to determine the impact of operating surgeon grade and level of supervision on the incidence of one-year patient mortality and all-cause revision following elective primary total hip replacement (THR). METHODS: National Joint Registry data from 2005 to 2020 for a single University Teaching Hospital were used, with analysis performed on the 15-year dataset divided into 5-year block periods (B1, 2005-2010; B2, 2010-2015; B3, 2015-2020). Outcome measures were mortality and revision surgery at one year, in relation to lead surgeon grade, and level of supervision for trainee-led (TL) operations. RESULTS: A total of 9,999 eligible primary THRs were performed, of which 5,526 (55.3%) were consultant-led (CL), and 4,473 (44.7%) TL. Of TL, 2,404 (53.7%) were nonconsultant-supervised (TU) and 2,069 (46.3%) consultant-supervised (TS). The incidence of one-year patient mortality was 2.05% (n=205), and all-cause revision was 1.11% (n=111). There was no difference in one-year mortality between TL and CL operations (p=0.20, odds ratio (OR) 0.78, confidence interval (CI) 0.55-1.10). The incidence of one-year revision was not different for TL and CL operations (p=0.15, OR 1.37, CI 0.89-2.09). Overall, there was no temporal change for either outcome measure between TL or CL operations. A significant increase in revision within one-year was observed in B3 between TU compared with CL operations (p=0.005, OR 2.81, CI 1.35-5.87). CONCLUSIONS: We found no difference in overall one-year mortality or all-cause revision rate between TL and CL primary THR. Despite a reduction in unsupervised THR in the latest five-year period (2015-2020), unsupervised TL THR resulted in an increased risk of early revision.