The analgesic effectiveness of contemporary motor-sparing nerve blocks used in combination for analgesia in total knee arthroplasty (TKA) is unclear. We conducted this network meta-analysis to evaluate the analgesic effectiveness of adding single-injection or continuous adductor canal block (ACB) with or without infiltration of the interspace between the popliteal artery and the capsule of the posterior knee (iPACK) to intraoperative local infiltration analgesia (LIA), compared to LIA alone, following TKA.
Randomized trials examining the addition of single-injection or continuous ACB with or without single-injection iPACK to LIA for TKA were considered. The two primary outcomes were area under the curve (AUC) pain scores and postoperative function over 24-48 hours. Secondary outcomes included rest pain scores at 0, 6, 12, and 24 hours, opioid consumption (0-24- and 25-48-hours), and incidence of nausea/vomiting. Network meta-analysis was conducted using a frequentist approach.
Twenty-seven studies (2,317 patients) investigating the addition of i) single-injection ACB, ii) continuous ACB, iii) single-injection ACB and single-injection iPACK, and iv) continuous ACB and single-injection iPACK to LIA, compared to LIA alone, were included. For AUC 24–48-hour pain, the addition of continuous ACB with single-injection iPACK displayed the highest p-score probability (89%) of being most effective for pain control. The addition of continuous ACB without single-injection iPACK displayed the highest p-score probability (87%) of being most effective for postoperative function.
Our results suggest that continuous ACB, but not single-injection ACB and/or single-injection iPACK, can provide statistically superior analgesia when added to LIA for TKA compared to LIA alone. However, the magnitude of these additional analgesic benefits is clinically questionable.