No Additive Analgesic Effect of Interspace Between Popliteal Artery and Capsule of the Knee Block Over Local Infiltration Analgesia Only Around Arthrotomy Site in Bilateral Total Knee Arthroplasty

Background: Local infiltration analgesia only around the arthrotomy site (LIAA) is simple and without risk of neurological injury.However, the clinical importance of posterior knee pain in one-stage bilateral total knee arthroplasty (BTKA) is still controversial.Our objective, therefore, was to determine the additive effect of posterior knee analgesia over LIAA.Methods: This study was a prospective randomized controlled trial with 45 patients who underwent BTKA.One knee was randomized to receive only LIAA, while the other knee received combined LIAA with the interspace between the Popliteal Artery and the Capsule of the Knee (iPACK) blocked.Visual analog scales (VASs) for pain in the anterior and posterior aspects of the knee at 6-96 hours postoperative, knee flexion angle, and active straight leg raise (SLR) were assessed.Results: The VAS of the anterior knee of the LIAA + iPACK group at 6, 12, 18, 24, 48, 72, and 96 hours postoperative were 6. 00, 5.80, 5.02, 4.58, 4.59, 3.54, and 3.51, respectively, as compared to 6.49, 6.02, 5.27, 4.99, 4.77, 3.71, and 3.76 of the sole LIAA group (P > .05).Likewise, the VASs of posterior knee of the LIAA + iPACK group were slightly lower than those of the sole LIAA group (4.16 vs 4.69, 3.38 vs 3.62, 2.94 vs 2.89, 2.66 vs 2.82, 2.98 vs 3.16, 2.38 vs 2.65, and 1.79 vs 1.96).The degree of knee flexion, and SLR were not different between groups at any time point.Conclusions: Posterior knee analgesia with iPACK has no additional benefit when the LIAA is performed.The anesthetic agent may be kept for other modalities to augment LIAA in BTKA.