Perioperative outcomes associated with general and spinal anesthesia after total joint arthroplasty for osteoarthritis: a large, Canadian, retrospective cohort study

BACKGROUND: Compared with general anesthesia, spinal anesthesia has many benefits for patients undergoing total hip (THA) or total knee (TKA) arthroplasty, but few studies have explored rates of morbidity and mortality. We aimed to compare perioperative outcomes by anesthetic type for patients undergoing THA or TKA for osteoarthritis. METHODS: We identified patients who underwent primary THA or TKA from the affiliated institute's database. We calculated inpatient, 30-day, 60-day and 90-day mortality rates, as well as 90-day perioperative complications, readmissions and length of stay (LOS). We compared outcomes between groups using logistic regression and propensity-adjusted multivariate analysis. RESULTS: We included 6100 (52.2%) patients undergoing THA and 5580 (47.8%) undergoing TKA. We found no differences by anesthetic type in mortality rates up to 90 days after surgery. Patients under spinal anesthesia were less likely to need a blood transfusion (THA odds ratio [OR] 0.75, 95% confidence interval [CI] 0.60 to 0.92; TKA OR 0.52, 95% CI 0.40 to 0.67) and were more likely to be discharged home among those who underwent TKA (OR 1.61, 95% CI 1.30 to 2.00). Patients who received spinal anesthesia for THA had a longer LOS (0.28 d, 95% CI 0.17 to 0.39), and patients who received spinal anesthesia for TKA had a shorter LOS than those who received general anesthesia (-0.34 d, 95% CI -0.51 to -0.18). Anesthetic type was not associated with any difference in adverse events. CONCLUSION: These findings may inform decisions on anesthetic type for total joint arthroplasty, especially for rapid discharge protocols. Further research is needed to understand postoperative pain and functional outcomes between anesthetic types.