EP043 Does the use of adductor canal blocks really affect knee osteoarthritis outcome scores among outpatient total knee arthroplasty patients?

<h3>Background and Aims</h3> A previous analysis from our group suggested that the use of peripheral nerve blocks may decrease hip and knee osteoarthritis outcome scores (HOOS/KOOS) among outpatient ( <h3>Methods</h3> Institutional review board (IRB) approval was obtained from the Mayo Clinic IRB. A retrospective review of 338 TKA patients was performed, including 202 patients who received an ACB. All patients received periarticular injections and multimodal analgesia. Intraoperative and post-anesthesia care unit (PACU) narcotic usage (oral morphine milligram equivalents, OME), numerical pain scores, first ambulation distance, length-of-stay (LOS), 90-day complications (readmissions or reoperations) and KOOS scores were compared. Pearson Chi-Square and Fisher’s Exact tests evaluated categorical variables and Wilcoxon-Mann-Whitney tests evaluated continuous variables. <h3>Results</h3> There were no significant differences in baseline values between the two groups. The mean patient age was 64.6 years, 54.1% were male, 89.1% were Caucasian, mean body mass index was 32.8 kg/mg2 and 91.1% of patients had a spinal anesthetic. Mean KOOS scores were not different for ACB patients compared to non-block patients (71.7 vs 64.0, respectively, p=0.0743). ACBs resulted in no significant differences in postoperative OME or pain scores. Additionally, PNB resulted in no difference in LOS (10.3 vs 11.2 hrs, p=0.1544), mean ambulation distance (147.5 vs 146.9 feet, p=0.9699) or 90-day complications. <h3>Conclusions</h3> Our results suggest that, within the context of a multimodal analgesia outpatient protocol, the use of ACB is not associated with an improvement in KOOS scores, 90-day complications or immediate postoperative outcome improvement. Among low-risk patients who qualify for an outpatient pathway with a multimodal analgesia protocol, the use of ACB may not influence postoperative functional and other outcomes.