Ultrasound-Guided Local Anesthetic Infiltration Between the Popliteal Artery and the Capsule of the Posterior Knee (IPACK) Block for Primary Total Knee Arthroplasty: A Systematic Review of Randomized Controlled Trials

Systematic reviews and meta-analyses in regional anesthesia and pain medicine (Part II): guidelines for performing the systematic review

In Part I of this series, we provide guidance for preparing a systematic review protocol. In this article, we highlight important steps and supplement with exemplars on conducting and reporting the results of a systematic review. We suggest how authors can manage protocol violations, multiplicity of outcomes and analyses, and heterogeneity. The quality (certainty) of the evidence and strength of recommendations should follow the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. It is our goal that Part II of this series provides valid guidance to authors and peer reviewers who conduct systematic reviews to adhere to important constructs of transparency, structure, reproducibility, and accountability. This will likely result in more rigorous systematic reviews being submitted for publication to the journals like Regional Anesthesia & Pain Medicine and Anesthesia & Analgesia.

Anesthesia for the Patient Undergoing Knee Procedures

Anesthesia for patients undergoing knee procedures encompasses a large patient population with significant variation in patient age, comorbidities, and type of surgery. In addition, these procedures are performed in vastly different surgical environments, including large academic hospitals, private hospitals, and out-patient surgical centers. These variabilities require a thoughtful and individualized anesthetic approach tailored toward the medical and surgical needs of each patient. This article discusses anesthetic approaches to patients with acute, subacute, and chronic knee-related pathology requiring surgery. We will also review pertinent knee anatomy and innervation and discuss regional nerve blocks and their applications to knee-related surgical procedures.

Investigation of Optimal Needle Position for Radiofrequency Ablation-Based Blockade of Interspace between the Popliteal Artery and the Posterior Capsule of the Knee: A Cadaveric Study

Background and Objectives: The interspace between the popliteal artery and the posterior capsule of the knee (iPACK) block has been widely used in perioperative settings to control posterior knee pain and can additionally be used for chronic knee pain. In this cadaveric study, we aimed to investigate the needle tip position and its proximity to the articular branch of the tibial nerve (ABTN) during an iPACK-targeted radiofrequency procedure. Materials and Methods: An ultrasound-guided iPACK block was performed on 20 knees of 10 cadavers. We injected 0.1 mL each of blue and green gelatinous dye near the tibial artery (point A) and posterior knee capsule (point B), respectively, and evaluated the spread of both around the ABTN. For a hypothetical conventional radiofrequency ablation (RFA) lesion (diameter, 2.95 mm) and cooled RFA lesion (diameter, 4.9 mm), we counted the number of specimens in which the ABTNs would be captured. Results: The percentage of specimens in which the ABTN would be captured by a cooled RFA lesion was 64.71% at point A and 43.75% at point B (p = 0.334). Meanwhile, the percentage of specimens in which the ABTN would be captured by a conventional RFA lesion was 58.82% from point A and 25% from point B (p = 0.065). Conclusions: When performing an RFA-based iPACK block, the needle tip may be positioned either lateral to the tibial artery or in the space between the posterior knee capsule and the tibial artery. However, more studies with larger samples are needed to verify these results before the clinical use of this procedure can be recommended.

Comparison of the popliteal artery and the capsule of the posterior knee (IPACK) block and the genicular nerve block in primary total knee arthroplasty: A prospective randomized trial

OBJECTIVES

To compare the efficacy of genicular block and interspace between the popliteal artery and the posterior capsule (IPACK) block in the reduction of postoperative pain, the need for rescue analgesics, and the effects on a range of motion (ROM) in patients with TKA.

METHODS

This prospective randomized controlled study was carried out between February and May 2023. Based on the block method, 60 participants were divided into three equal groups. These groups included the IPACK block group (n=20), the genicular block group (n=20), and control group (n=20). Western Ontario and McMaster Universities Arthritis Index (WOMAC), Knee Society score (KSS) and Oxford Knee score (OKS) were used for clinical evaluation in the postoperative period.

RESULTS

The KSS and OKS scores of the IPACK and GNB were significantly lower than the control group (p<0.001, p<0.001). The timed up and go (TUG) values of the IPACK and GNB groups at 12th and 24th hour were significantly lower than the control group (p<0.001, p<0.001). The Tramadol rescue values of the IPACK block and control groups were significantly higher than the GNB group (p=0.028, p=0.001, respectively). The ROM values of the IPACK and GNB groups were significantly higher than the control group (p<0.001, p<0.001).

CONCLUSION

Both GNB and IPACK blocks had a significant positive impact on postoperative pain scores within the initial 24 hours following total knee arthroplasty (TKA). In comparison with IPACK, GNB had lower opioid consumption in the early postoperative period while also promoting better mobilization.

Systematic Reviews and Meta-analyses in Regional Anesthesia and Pain Medicine (Part II): Guidelines for Performing the Systematic Review

In Part I of this series, we provide guidance for preparing a systematic review protocol. In this article, we highlight important steps and supplement with exemplars on conducting and reporting the results of a systematic review. We suggest how authors can manage protocol violations, multiplicity of outcomes and analyses, and heterogeneity. The quality (certainty) of the evidence and strength of recommendations should follow the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. It is our goal that Part II of this series provides valid guidance to authors and peer reviewers who conduct systematic reviews to adhere to important constructs of transparency, structure, reproducibility, and accountability. This will likely result in more rigorous systematic reviews being submitted for publication to the journals like Regional Anesthesia & Pain Medicine and Anesthesia & Analgesia .

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

INTRODUCTION

This study aimed to investigate pain management, functional recovery, and stress response expressed by the neutrophile-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) after the popliteal artery and posterior knee capsule infiltration (iPACK) block combined with adductor canal block (ACB) in total knee arthroplasty (TKA).

PATIENTS AND METHODS

This was a prospective, double-blinded, randomised, controlled trial in a tertiary referral hospital. Three hundred and sixty-six patients were randomly allocated into the sham block group and iPACK combined with the ACB group. The primary outcome was postoperative pain scores. The secondary outcomes were opioid consumption, functional recovery expressed by a range of motion, and quadriceps strength. Also, the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were calculated.

RESULTS

There were significant differences between the sham block and iPACK + ACB group in pain scores p < 0.0001 at all time points. Therefore, there was a significant difference in opioid consumption (p < 0.0001) and functional recovery (p < 0.0001). Also, NLR and PLR levels 12 h (p < 0.0001) and 24 h (24 h) after surgery (p < 0.0001) were much lower in the iPACK + ACB group.

CONCLUSION

After total knee arthroplasty, the iPACK combined with ACB block group improved pain management, functional recovery, and stress response. Therefore, we strongly recommend this technique as a part of a multimodal analgesia protocol in knee surgery.

The Effects of Intraoperative Remifentanil Infusion on Postoperative Opioid Consumption in Patients Who Underwent Total Knee Arthroplasty with Femoral Nerve Block

(1) Background: Remifentanil is used for intraoperative pain control; however, it has several side effects, such as hypotension and opioid-induced hyperalgesia. We aimed to determine whether an intraoperative remifentanil infusion may increase postoperative opioid consumption in patients undergoing total knee arthroscopy (TKA) under femoral nerve block (FNB) in addition to general anesthesia. (2) Methods: We randomly assigned 66 patients who underwent total knee arthroplasty to the remifentanil (R) and control (C) groups. All patients underwent FNB and popliteal artery and posterior capsule of the knee (iPACK) block in addition to sevoflurane-based general anesthesia. Postoperative pain control was achieved using intravenous patient-controlled analgesia (IV-PCA) fentanyl. We recorded IV-PCA fentanyl consumption at various postoperative timepoints, numerical rating scale (NRS) scores, intraoperative changes in vital signs and index of nociception (qNOX), ephedrine consumption, postoperative side effects, satisfaction, and sleep quality. (3) Results: The primary outcome (the cumulative IV-PCA fentanyl usage within 48 h postoperatively) was significantly lower in the C group (541.1 ± 294.5 µg) than in the R group (717.5 ± 224.0 µg) (p < 0.001). The secondary outcome (the cumulative IV-PCA fentanyl usage within 12, 24, and 72 h) was lower in the C group than in the R group and the mean arterial pressure was lower in the R group than in the C group from immediately after tourniquet on to immediately after tourniquet off. The heart rate was lower in the R group from immediately after incision to immediately after irrigation. There was no significant between-group difference in the perioperative qNOX and NRS scores at rest and activity except for NRS scores at 72 h postoperatively. Ephedrine use was higher in the R group than in the C group (p = 0.003). There was no significant between-group difference in the incidence of postoperative nausea and vomiting, nor in the postoperative satisfaction and sleep quality. (4) Conclusions: Avoiding intraoperative remifentanil infusion may reduce total opioid consumption in patients undergoing FNB before TKA.

Surgeon-Directed Arthroscopic Infiltration Between the Popliteal Artery and Capsule of the Knee (IPACK) Block: Technical Description

Advances in regional anesthesia techniques for knee surgery have led to drastic improvements in postoperative pain control and have reduced reliance on perioperative opioid analgesics. The infiltration between the popliteal artery and capsule of the knee (IPACK) block has been a useful tool for providing posterior knee analgesia as an adjuvant to traditional femoral or adductor canal blocks in knee surgery. We present a simple and reproducible technique for the arthroscopic administration of this block.

The Ramifications of Opioid Utilization and Outcomes of Alternative Pain Control Strategies for Total Knee Arthroplasties

Morbidity and mortality related to opioid use has generated a public health crisis in the United States. Total knee arthroplasty (TKA) is an increasingly common procedure and is often accompanied by post-operative opioid utilization. Unfortunately, post-operative opioid usage after TKA has been shown to lead to higher rates of complications, longer hospital stays, increased costs, and more frequent need for revision surgery. Pre-operative opioid utilization has been shown to be one of the most important predictors of post-operative opioid usage. Additional risk factors for continued post-operative opioid utilization after TKA include pre-operative substance and tobacco use as well as higher post-operative prescription dosages, younger age, female gender, and Medicaid insurance. One method for mitigating excessive post-operative opioid utilization are Enhanced Recovery After Surgery (ERAS) protocols, which include a multidisciplinary approach that focuses on perioperative factors to optimize patient recovery and function after surgery. Additional strategies include multimodal pain regimens with epidural anesthetics, extended duration local anesthetics and adjuvants, and ultrasound guided peripheral nerve blocks. In recent years, opioid prescribing duration limitations have also been put into place by state and federal government, hospital systems, and ambulatory surgery centers making effective acute pain management imperative for all stakeholders. In this regard, as rates of TKA continue to increase across the United States, multidisciplinary efforts by all stakeholders are needed to ensure adequate pain control while preventing the negative sequalae of opioid medications.

Anesthesia for the Patient Undergoing Knee Procedures

Anesthesia for patients undergoing knee procedures encompasses a large patient population with significant variation in patient age, comorbidities, and type of surgery. In addition, these procedures are performed in vastly different surgical environments, including large academic hospitals, private hospitals, and out-patient surgical centers. These variabilities require a thoughtful and individualized anesthetic approach tailored toward the medical and surgical needs of each patient. This article discusses anesthetic approaches to patients with acute, subacute, and chronic knee-related pathology requiring surgery. We will also review pertinent knee anatomy and innervation and discuss regional nerve blocks and their applications to knee-related surgical procedures.

Comparison of Genicular Nerve Block in Combination With Adductor Canal Block in Both Primary and Revision Total Knee Arthroplasty: A Retrospective Case Series

The management of pain in patients undergoing total knee arthroplasty (TKA) for chronic knee osteoarthritis (OA) has remained a challenge for the anesthesiologist regarding regional anesthesia as no single regional technique is adequate with regard to balancing effective analgesia with minimal muscle weakness. Severe postoperative pain following TKA has been shown to negatively impact patient outcomes and mortality. The genicular nerve block has recently been demonstrated to provide effective analgesia to the anterior and posterior knee capsule in recent studies. In this retrospective case series, we compare the efficacy of combined genicular nerve block (GNB) and adductor canal block (ACB) to only ACB in both primary and revision TKA patients. This combined novel approach for TKA patients can be utilized to improve patient pain scores and early ambulation, limiting the use of opioids and early discharge.