Is a Failed Spinal Attempt Associated with a Worse Clinical Course Following Primary Total Hip and Knee Arthroplasty?

Introduction Spinal anesthesia (SA) is the preferred anesthesia modality for total joint arthroplasty (TJA). However, studies establishing SA as preferential may be subject to selection bias given that general anesthesia (GA) is often selectively utilized on more difficult, higher-risk operations. The optimal comparison group, therefore, is the patient converted to GA due to a failed attempt at SA. The purpose of this study was to determine risk factors and outcomes following failed SA with conversion to GA during primary total hip (THA) or knee arthroplasty (TKA). Methods A consecutive cohort of 4,483 patients who underwent primary TJA at our institution was identified (2,004 THA and 2,479 TKA). Of these patients, 3,307 underwent GA (73.8%), 1,056 underwent SA (23.3%), and 130 patients failed SA with conversion to GA (2.90%). Primary outcomes included rescue analgesia requirement in the post-anesthesia care unit (PACU), time to ambulation, pain scores in the PACU, estimated blood loss (EBL), and 90-day complications. Results Risk factors for SA failure included older age and a higher comorbidity burden. Failure of SA was associated with increased EBL, rescue intravenous (IV) opioid use, and time to ambulation when compared to the successful SA group in both THA and TKA patients (P < 0.001). The anesthesia modality was not associated with significant differences in PACU pain scores. The 90-day complication rate was similar between the failed SA and GA groups. There was a higher incidence of post-operative pain prompting unplanned visits and thromboembolism when comparing failed SA to successful SA in both THA and TKA patients (P < 0.05). Conclusion In our series, patients who had failed SA demonstrated inferior outcomes to patients receiving successful SA and similar outcomes to patients receiving GA who did not have an SA attempt. This emphasizes the importance of success in the initial attempt at SA for optimizing outcomes following TJA.