Abstract
Background: Total knee arthroplasty (TKA) is associated with intense postoperative pain, for which continuous femoral triangle block (FTB) and infiltration between the popliteal artery and the capsule of the posterior knee (iPACK) block have been used. Genicular nerves supply sensation to a part of the knee joint that the two blocks do not affect, so we recently started adding genicular nerve blocks (GNBs) to the combination of FTB and iPACK block. In this retrospective study, we examined to see if the addition of GNBs benefited patients undergoing TKA. Methods: We conducted a retrospective analysis of data that had been collected prospectively from patients undergoing TKA and receiving our standard analgesic regimen including continuous FTB and iPACK block in our hospital. We compared patients with and without GNBs regarding intra- and postoperative data including the time needed for block performance, visual analog scale (VAS) pain scores, analgesic requirements, and adverse events. The two-tailed Student's t test, Mann-Whitney U test, chi-square test, and Fisher's exact test were used for statistical analysis. Results: Seventy-four patients including 41 and 33 patients with and without GNBs, respectively, were evaluated. The demographics of the patients were comparable. VAS pain score at rest on postoperative day 1 was not different between patients who received GNBs and those who did not (20 [0-36] vs. 25 [19-45] in median [IQR], p = 0.205). Other measurements related to postoperative pain were also similar throughout the two postoperative days. No severe complications related to blocks were observed. Conclusion: The results of this exploratory retrospective study suggest that the additional benefits of GNBs, if any, are limited for the early postoperative period when combined with continuous FTB and iPACK block in patients undergoing TKA. However, larger, sufficiently powered, and more robust clinical trials are needed to confirm the present results.