Comparative Efficacy of iPACK vs Popliteal Sciatic Nerve Block for Pain Management Following Total Knee Arthroplasty: A Retrospective Analysis.

Introduction Total knee arthroplasty (TKA) is associated with severe acute postoperative pain. The use of tourniquets and drains (T/D) is common in TKA but may have an influence on postoperative pain and muscular strength. The infiltration of local anesthetic between the popliteal artery and capsule of the knee (iPACK block) is a motor-sparing block that provides analgesia to the posterior aspect of the knee. However, evidence regarding its efficacy is scarce. This study aims to assess the effectiveness of iPACK block and the impact of T/D use on pain and muscular strength after TKA. Material and methods A retrospective study was carried out including patients who underwent TKA from January 2020 to April 2023. Patients were allocated into groups according to the peripheral nerve block performed and T/D use. Results We included 415 patients in this study. No differences were found in pain at rest or the need for rescue analgesia between patients who received an iPACK block or sciatic nerve block (SNB) with T/D applied. Patients who received a SNB reported lower pain scores on movement (p = 0.019), but with a higher prevalence of motor block (p < 0.001). Patients who underwent surgery without using T/D reported lower pain scores on movement (p = 0.021) and reduced need for rescue analgesia (p = 0.041). Conclusion These findings indicate that iPACK block can facilitate early mobilization after TKA without significant impact on postoperative muscle strength. Furthermore, the use of a T/D may be a source of postoperative pain that could compromise early rehabilitation.