Spinal Versus General Anesthesia in Total Knee Arthroplasty: Are There Differences in Complication and Readmission Rates?

BACKGROUND: Spinal anesthesia (SP) utilization continues to expand in total knee arthroplasty (TKA). However, little is known regarding differences in complication rates between spinal and general anesthesia used for primary TKA. Therefore, the purpose of this study is to compare the length of stay (LOS), operative time, and readmission and revision rates between patients who received spinal and general anesthesia during TKA. METHODS: The American Joint Replacement Registry (AJRR) was used to identify primary elective TKA patients from 2017 to 2020. Patients were divided into 2 cohorts, general (GN) and SP, based on the mode of anesthesia administered during the index surgery. In total, 270,251 TKAs were identified, of which 126,970 (47.0%) received general anesthesia and 143,281 (53.0%) received spinal anesthesia. Length of stay, operative time, 90-day readmission, and 90-day revisions were compared between the 2 groups. Multivariable logistic regression analyses were used to adjust for potential confounders. RESULTS: After accounting for confounding factors, SP was associated with a lower risk of having a LOS greater than 3 days (odds ratio [OR] 0.470, 95% confidence interval [CI] 0.454-0.487, P < .0001), but a slightly higher likelihood of having a longer operative time (OR 1.075, 95% CI 1.056-1.094, P < .0001). SP was also linked to lower rates of 90-day readmission (OR 0.845, 95% CI 0.790-0.904, P < .0001) and lower risk of 90-day all-cause revision (OR 0.506, 95% CI 0.462-0.555, P < .0001). CONCLUSION: SP was associated with a lower 90-day readmission rate and a lower risk of 90-day revision. These findings support the best practice guidelines of The Joint Commission to use spinal anesthesia when possible as part of an enhanced recovery after surgery (ERAS) pathway.