Analgesic Effectiveness of Motor-sparing Nerve Blocks for Total Knee Arthroplasty: A Network Meta-analysis

Abstract

Background 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. Methods 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. Results 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. Conclusions 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.

Pain Management, Functional Recovery, and Stress Response Expressed by NLR and PLR after the iPACK Block Combined with Adductor Canal Block for Total Knee Arthroplasty—A Prospective, Randomised, Double-Blinded Clinical Trial

“…The iPACK block is a relatively novel ultrasound-guided regional anaesthesia technique designed to block the small articular sensory branches of the popliteal plexus and the obturator nerve, resulting in analgesia of the posterior knee capsule. iPACK blockade targets the pain sensation below the knee and can relieve pain behind the knee without causing muscle weakness [9,23]. Therefore, the iPACK block, together with ACB, may be an effective tool for analgesia after TKA.…”

“…The iPACK block was designed to hit the posterior terminal sensory nerve branches [8]. Despite two meta-analyses concerning the iPACK and ACB in TKA [9,10], there is no unity regarding whether the iPACK added to ACB reduces pain scores and opioid consumption and promotes functional recovery.…”

Regional Anesthesia for Knee Surgery: Finding Positives in the Negatives

“…The abovementioned margin is reasonable considering that the minimum clinically important difference (MCID) for TKA has been reported as 1.6 to 2.2 NRS units. 5 The aims are (1) to demonstrate the lack of statistically significant difference in postoperative pain and (2) to show that the confidence interval excludes the a priori NRS margin.…”

“…Third, some may argue that LIA constitutes the essential, cornerstone intervention in post-TKA analgesia, and any additional interventions added to LIA yield incremental benefits that are not clinically important. 1 Therefore, based on this work, an interesting future trial design would be to examine saline versus active ACB and iPACK in the setting of LIA. The approach in the current study by YaDeau et al seems to suggest that LIA is not the gold standard by attempting to prove that a placebo treatment is not worse than LIA.…”

“…Numerous investigations have assessed various regional techniques for total knee arthroplasty (TKA) including femoral nerve block, adductor canal block (ACB), genicular nerve blocks, infiltration between the popliteal artery and posterior capsule of the knee (iPACK), and periarticular local infiltration (LIA). 1 The simplest of approaches is for all patients undergoing TKA to receive LIA. In practice, there is a regional anesthetic “à la carte menu” whereby clinicians pick and choose the regimen that they believe has the best evidence.…”