Efficacy of early postoperative ultrasound-guided femoral nerve block (FNB) combined with an infiltration block between the popliteal artery and the capsule of the knee (IPACK) compared to FNB alone for total knee arthroplasty (TKA)

Background This study aimed to assess the effectiveness of combining FNB with an IPACK, compared with FNB alone, for early postoperative pain management after total knee arthroplasty (TKA). This novel technique may significantly improve posterior knee pain control and potentially lead to earlier and better functional outcomes for patients. Materials and methods This prospective observational study was conducted between September 2023 and June 2024. The initial 40 consecutive patients received FNB+IPACK, and the subsequent 40 received FNB alone. All patients were evaluated with the visual analog scale (VAS) for pain; the Timed Up & Go (TUG) test for walking and balance; the manual muscle testing (MMT) for muscle strength; range of motion (ROM) for joint flexibility; and anesthesia consumption for preoperative and postoperative pain recorded at 8, 24, and 48 hours. This study assessed various analgesic techniques for pain management and functional outcomes. Results The FNB+IPACK group experienced significantly lower postoperative pain levels at 8, 24, and 48 hours compared with the FNB group ( P < 0.001). Resting pain was significant at the first 8 hours. At 24 hours, the walking VAS score was 3[2-3], with a TUG time of 22[21-23] (both P < 0.001). By 48 hours, the walking VAS score decreased to 1[1-1.75], and the TUG time improved to 18[17-19] (both P < 0.001), reflecting continued pain reduction and increased mobility. Conclusions The FNB+IPACK technique was an excellent analgesic strategy for the TKA postoperative period without adverse effects on motor function.