Inter-hospital variation in early major complication rates following total hip arthroplasty: a population-based study

PurposeEarly major complications following total hip replacement (THR) occur rarely, but given the high volumes of THR, represent a major burden to patients and the system. The purpose of this study was to determine the influence of hospital-level surgical practices on early major complications across Ontario.MethodsWe conducted a population-based retrospective cohort study of all adults in Ontario, Canada who underwent primary THR for osteoarthritis between January 1, 2009 and December 31, 2019. The primary outcome was early major surgical complications (composite of deep infection, periprosthetic fracture, dislocation, or revision surgery occurring within 1 year of surgery). Medical complications (thromboembolism, myocardial infarction, pneumonia) occurring within 30 days of surgery also were assessed. THR performed at centres with very low volumes were excluded a priori. Two-level hierarchical logistic regression models adjusted for age, sex and Charlson co-morbidity score were used to calculate each hospital's unique adjusted complication rate and 95% confidence interval.ResultsDuring the study period, 95,912 patients (mean [SD] age 67 [11.0] years; 51,216 (53.4%) women) underwent THA at 56 hospitals across Ontario. Overall, 1,656 (1.7%) patients had a major surgical complication within 1 year. Major surgical complication rates varied seven fold between hospitals from 0.6 to 4.1%. After adjustment, 4 of 56 hospitals were low outliers (adjusted complication rate significantly below average) and 5 of 56 were high outliers (adjusted complication rate significantly above average). There were no hospital outliers for medical complications.ConclusionsThere was significant variation in early major surgical complication rates between Ontario hospitals that persisted after adjustment for patient age, sex and medical comorbidity. Feeding back adjusted outcomes in benchmarking reports may enable individual hospitals and surgeons better consider their own performance and scale up best practices from low outlier hospitals, which can play a role in educating other centres in their region.