Analgesic efficacy of adding the IPACK block to a multimodal analgesia protocol for primary total knee arthroplasty

Effects of popliteal plexus block after total knee arthroplasty: a randomized clinical trial

BACKGROUND AND OBJECTIVES

Motor-sparing peripheral nerve blocks enhance multimodal opioid-sparing strategies after total knee arthroplasty. We hypothesized that adding a popliteal plexus block to a femoral triangle block could reduce 24-hour opioid consumption after total knee arthroplasty, compared with standalone femoral triangle block or adductor canal block.

METHODS

This patient- and assessor-blinded, randomized controlled trial allocated 165 patients into three equally sized parallel groups, receiving either 1) popliteal plexus block+femoral triangle block, 2) femoral triangle block, or 3) adductor canal block. Intravenous oxycodone was administered via patient-controlled analgesia pumps. The primary outcome was 24-hour postoperative opioid consumption. Secondary outcomes were preoperative maximum voluntary isometric contraction and manual muscle tests of knee and ankle movement assessed before and after the nerve block procedure together with postoperative pain scores, mobilization, and 12-hour opioid consumption.

RESULTS

24-hour postoperative intravenous oxycodone consumption varied significantly between groups (p<0.01), with medians (IQR) of 6 mg (2-12) in the popliteal plexus block+femoral triangle block group, 10 mg (8-16) in the femoral triangle block group, and 12 mg (6-18) in the adductor canal block group. Median consumption in the popliteal plexus block+femoral triangle block group was reduced by -4 mg (95% CI -7.4 to -1.0, p<0.01) and -6 mg (95% CI -8.3 to -1.3, p=0.01) compared with groups of femoral triangle block and adductor canal block, respectively. No differences were found in pain scores, mobilization, or changes in preoperative muscle strength. Post hoc analysis revealed successful 24-hour opioid-free postoperative care among 12 patients with popliteal plexus block+femoral triangle block, as compared with two with femoral triangle block and six with adductor canal block.

CONCLUSION

Adding a popliteal plexus block to a femoral triangle block resulted in a statistically significant reduction of 24-hour postoperative opioid consumption after total knee arthroplasty. However, no differences were found in pain scores. Popliteal plexus block did not impair the lower leg muscles.

Infiltration of local anesthetic in the Interspace between the popliteal artery and capsule of the posterior knee "IPACK block" versus adductor canal block "ACB" for pain relief after open wedge high tibial osteotomy: a randomized clinical trial

BACKGROUND

A high tibial osteotomy is usually associated with severe postoperative pain. Both adductor canal block (ACB) and interspace between the popliteal artery and capsule of the posterior knee (IPACK) have been described as effective block techniques for providing analgesia after knee surgeries, with few comparisons in wedge osteotomy cases. We aim to compare the postoperative analgesic profile of the previously mentioned two block techniques in patients undergoing tibial osteotomies.

METHODS

Sixty patients were enrolled in this randomized prospective trial (30 received IPACK and 30 received ACB). Both blocks were installed before the spinal anesthesia after infiltration of 2 mL lidocaine 2%. Twenty mL of bupivacaine 0.25% mixed with dexamethasone as anesthetic adjuvant were used for both blocks. The postoperative analgesic profiles were compared between the two groups.

RESULTS

Postoperative pain scores were lower in the IPACK group, and that decrease was evident throughout the first 10 hours postoperatively. Additionally, the duration of analgesia was much prolonged with the same block (487.50±82.39 vs. 301.93±92.06 minutes with ACB). There was a significant decline in postoperative analgesic consumption (1.27±0.45 vs. 1.8±0.61 gm, P=0.000), and a significant increase in the ambulation distance (19.10±0.60 vs. 17.73±0.45 m, P=0.000) with a significant decline in the duration of hospitalization (43.27±7.61 vs. 54±8.35 hours) in the IPACK group compared to the ACB group.

CONCLUSIONS

IPACK is a superior block technique compared to ACB in patients undergoing high tibial osteotomy regarding postoperative analgesia, ambulation distance, and patient satisfaction with little rate of adverse events in both groups.

A cadaveric study investigating the spread of injectate following an interspace between the popliteal artery and the capsule of the posterior knee block in a neonatal sample: a pilot study

The infiltration of the interspace between the popliteal artery and the capsule of the posterior knee (IPACK) block, is a novel ultrasound-guided technique used for postoperative pain management of the knee. The success of the block is attributed to the spread of injectate between the capsule of the knee and the popliteal artery. This novel technique is believed to target the articular branches of the tibial, common fibular (peroneal) and obturator nerves. However, the extent of the spread in a paediatric population is unknown. Therefore, this study aims to evaluate the spread of the IPACK block. Using ultrasound guidance, the IPACK block was replicated bilaterally in neonatal cadavers. Methylene blue dye (0.3 ml/kg) was injected proximally and distally. Subsequently, cadavers were dissected to determine the injectate spread. Proximal injections resulted in staining of some of the articular branches, while the distal injections resulted in staining of all four articular branches. Additional staining of the superior lateral and medial genicular nerves was noted irrespective of the technique. Overall, both injections resulted in posterior, anterolateral spread with limited medial spread. Results from this study reveal preservation of the main nerve trunks following the proximal technique, while the distal technique displayed greater staining of the articular branches. We believe that the block can be seen as a more holistic and viable alternative to lower limb blocks for the paediatric population, as it allows for a wider spread in the posterior and medial-lateral compartments of the knee.

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.

Efficacy of adding infiltration between the popliteal artery and the capsule of the posterior knee (IPACK) to adductor canal block and local infiltration analgesia in total knee arthroplasty: A retrospective cohort study

OBJECTIVE

Local infiltration analgesia (LIA), adductor canal block (ACB), and infiltration between the popliteal artery and the capsule of the posterior knee (IPACK) are popular multimodal analgesia techniques used during total knee arthroplasty (TKA). This study aimed to explore the efficacy of adding the IPACK technique to ACB and LIA in patients undergoing TKA.

METHODS

In this retrospective cohort study, patients who underwent primary unilateral TKA were divided into two groups based on their date of admission. Sixty-three patients underwent IPACK, ACB and LIA (IPACK group) during surgery, while 60 patients underwent ACB and LIA (control group). The primary outcome was the postoperative administration of morphine hydrochloride as a rescue analgesic. Secondary outcomes included time to first rescue analgesia, postoperative pain assessed using the visual analog scale (VAS), functional recovery assessed by knee range of motion and ambulation distance, time until hospital discharge, and complication rates.

RESULTS

The two groups were similar in average postoperative 0-to-24-h morphine consumption (11.8 mg for the control group vs 12.7 mg for the IPACK group, p = .428) and average total morphine consumption (18.2 mg vs 18.0 mg, p = .983) during hospitalization. There were also no significant differences in the secondary outcomes.

CONCLUSIONS

The addition of IPACK to ACB and LIA did not provide any clinical analgesic benefits. Orthopedic surgeons and anesthesiologists are justified in using ACB and LIA without IPACK for TKA.

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 .

Periarticular injection, iPACK block, and peripheral nerve block in pain management after total knee arthroplasty: a structured narrative review

INTRODUCTION

Total knee arthroplasty (TKA) is commonly performed in patients with end-stage osteoarthritis or rheumatoid arthritis of the knee to reduce joint pain, increase mobility, and improve quality of life. However, TKA is associated with moderate to severe postoperative pain, which remains a significant clinical challenge. Surgeon-administered PAI and anesthesiologist-administered iPACK have proven viable alternatives to conventional peripheral nerve blocks. This review aims to discuss which IPACK block or periarticular injection, combined or not with different peripheral nerve blocks, has better effects on postoperative rehabilitation, patient satisfaction, and overall outcome.

MATERIAL AND METHODS

The literature review was performed on standards of care, current therapeutic options, a pain management protocol, and innovative treatment options for patients undergoing total knee arthroplasty. The literature was reviewed through four electronic databases: PubMed, Cochrane Library, Google Scholar, and Embase.

RESULTS

The initial search yielded 694 articles. Fifty relevant articles were selected based on relevance, recentness, search quality, and citations. Six studies compared PAI to peripheral nerve block (PNB), and eight studies checked the effectiveness of adding PNB to PAI. Three studies compared iPACK to PNB, and ten reviewed the point of adding PNB to iPACK.

CONCLUSIONS

The literature review indicates that the best analgesic effect is obtained by combining PAI or iPACK with a peripheral nerve block, particularly with ACB, due to its analgesic, motor-sparing effect, and satisfactory analgesia.

Comparison of Different Concentrations of Ropivacaine Used for Ultrasound-Guided Adductor Canal Block + IPACK Block in Total Knee Arthroplasty

This study aimed to compare the analgesic efficacy of different concentrations of ropivacaine used for the combination of ultrasound-guided adductor canal block (ACB) and infiltration between the popliteal artery and capsule of the posterior knee (IPACK) block in total knee arthroplasty (TKA). Before general anesthesia, 90 patients undergoing TKA were randomized to receive ACB + IPACK block with ropivacaine 0.2, 0.25, or 0.3% (defined as group A, B, and C, respectively). Primary outcome was the reported visual analog scale (VAS) pain scores at rest 30 minutes following arrival to the postanesthesia care unit (PACU). Secondary outcomes were postoperative VAS pain scores, postoperative morphine consumption, the time to first rescue analgesia, functional recovery of knee (including the range of motion and quadriceps strength), and postoperative complications. Compared with group A, group B and group C had significantly lower VAS scores 30 minutes following arrival to the PACU (p < 0.001 and p < 0.001, respectively). These two groups also had significantly lower VAS pain scores at postoperative 2 hours (at rest: p = 0.037 and 0.002; during motion: p = 0.035 and 0.001, respectively) and 6 hour (at rest: p = 0.033 and 0.002; during motion: p < 0.001 and p < 0.001, respectively), lower postoperative morphine consumption (p = 0.001 and 0.002, respectively), longer time to first rescue analgesia (p = 0.010 and 0.009, respectively), and better range of knee motion on the day of surgery (p = 0.008 and 0.002, respectively). Group B and group C showed no significant differences in these outcomes between each other (p > 0.05). The three groups did not show a significant difference in postoperative quadriceps strength and complication rates (p > 0.05). Compared with ropivacaine 0.2%, ropivacaine 0.25 and 0.3% can provide early pain relief in the first 6 hours after surgery. Ropivacaine 0.25 and 0.3% may provide more clinical benefits for patients undergoing outpatient TKA.

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

BACKGROUND

The analgesic effectiveness of contemporary motor-sparing nerve blocks used in combination for analgesia in total knee arthroplasty is unclear. This network meta-analysis was conducted 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, after total knee arthroplasty.

METHODS

Randomized trials examining the addition of single-injection or continuous ACB with or without single-injection block at the iPACK to LIA for total knee arthroplasty were considered. The two primary outcomes were area-under-the-curve pain scores over 24 to 48 h and postoperative function at greater than 24 h. Secondary outcomes included rest pain scores at 0, 6, 12, and 24 h; opioid consumption (from 0 to 24 h and from 25 to 48 h); and incidence of nausea/vomiting. Network meta-analysis was conducted using a frequentist approach.

RESULTS

A total of 27 studies (2,317 patients) investigating the addition of (1) single-injection ACB, (2) continuous ACB, (3) single-injection ACB and single-injection block at the iPACK, and (4) continuous ACB and single-injection block at the iPACK to LIA, as compared to LIA alone, were included. For area-under-the-curve 24- to 48-h pain, the addition of continuous ACB with single-injection block at the iPACK displayed the highest P-score probability (89%) of being most effective for pain control. The addition of continuous ACB without single-injection block at the iPACK displayed the highest P-score probability (87%) of being most effective for postoperative function.

CONCLUSIONS

The results suggest that continuous ACB, but not single-injection ACB and/or single-injection block at the iPACK, provides statistically superior analgesia when added to LIA for total knee arthroplasty compared to LIA alone. However, the magnitude of these additional analgesic benefits is clinically questionable.

EDITOR’S PERSPECTIVE

Integrating IPACK (Interspace between the Popliteal Artery and Capsule of the Posterior Knee) Block in an Enhanced Recovery after Surgery Pathway for Total Knee Arthroplasty-A Prospective Triple-Blinded Randomized Controlled Trial

We explored the efficacy of an interspace between the popliteal artery and capsule of the posterior knee (IPACK) block when added to an established enhanced recovery after surgery (ERAS) pathway to assist with posterior knee analgesia and functional mobility after total knee arthroplasty (TKA). We recruited participants undergoing TKA in our prospective, randomized, triple-blinded controlled trial. All study patients participated in our ERAS pathway consisting of a primary spinal anesthetic, adductor canal nerve catheter, and periarticular joint infiltration. Patients were randomized to receive an IPACK block or no block. The primary outcome was total postoperative opioid consumption. Secondary outcomes included pain scores, recovery unit length of stay, time to first opioid use, the incidence of posterior knee pain, ambulation distance and activities of daily living on postoperative day 1, and hospital length of stay. A total of 96 patients were randomized to the control and IPACK groups. There were no statistical differences in primary or majority of secondary outcomes. There was a lower incidence of posterior knee pain (39%) in the IPACK group when compared with controls (8.7%), p < 0.01. In terms of opioid consumption and a majority of functional outcomes, our study demonstrates no overall benefits of adding an IPACK block in this ERAS pathway in TKA. Nevertheless, IPACK may have the potential of mitigating posterior knee pain after TKA.

LEVEL OF EVIDENCE

level 1.

CLINICAL TRIAL NUMBER AND REGISTRY URL

NCT03653416. www.

CLINICALTRIALS

gov.

Comparison of Analgesic Efficacies of the iPACK (Interspace Between the Popliteal Artery and Capsule of the Posterior Knee) and Genicular Nerve Blocks Used in Combination With the Continuous Adductor Canal Block After Total Knee Arthroplasty: A Randomized Clinical Trial

BACKGROUND

The interspace between the popliteal artery and capsule of the posterior knee (iPACK) block and the genicular nerve block (GNB) are motor-sparing nerve blocks used for knee pain relief. We compared the analgesic efficacies of ultrasound-guided iPACK block and GNB when combined with continuous adductor canal block after total knee arthroplasty.

METHODS

In this randomized control study, 132 total knee arthroplasty patients were assigned to the iPACK, GNB, and iPACK + GNB groups. All patients received combined spinal anesthesia and continuous adductor canal block. The primary outcome was the 8-hour postoperative pain score during movement. Secondary outcomes were pain scores, posterior knee pain, intravenous morphine consumption, and tibial and common peroneal nerve sensorimotor function. All included patients completed the study.

RESULTS

The 4-hour and 8-hour postoperative pain scores during movement were significantly lower in the iPACK + GNB group than that in the iPACK group (-2.5 [3.6, 1.3]; P < .001 and -2 [-3, -1]; P < .001, respectively). The differences in rating pain scores and posterior knee pain were not clinically relevant. The iPACK group demonstrated a significantly higher intravenous morphine consumption than did the GNB and iPACK + GNB groups during the first 48 hours postoperatively (P < .001) but were not clinically relevant. There was no incidence of complete sensorimotor blockade in any of the groups.

CONCLUSION

The iPACK-GNB combination relieved pain during movement better than the iPACK block alone during the 8 hours postoperatively after total knee arthroplasty in setting of multimodal analgesia such as adductor canal block.

Clinical effects of interspace between the popliteal artery and capsule of the posterior knee block with multimodal analgesia for total knee arthroplasty: a systematic review and meta-analysis

PURPOSE

Combination of regional anaesthesia technique that is most effective in analgesia and postoperative functional outcome with the fewest complications needs investigation. Interspace between the popliteal artery and the capsule of the posterior knee block (IPACK) has been introduced clinically. We evaluated the efficacy of IPACK in combination with other nerve blocks after total knee arthroplasty.

METHODS

Data were obtained from PubMed, Cochrane Library, Web of Science, and Sciencedirect. Studies that compared outcomes using IPACK combined with other regional nerve blocks after total knee arthroplasty with other analgesic modalities and those which used pain scores or opioid consumption as primary or secondary outcomes were included.

RESULTS

Seventeen articles (20 trials, 1652 patients) were included. IPACK supplementation significantly reduced rest pain scores after total knee arthroplasty at postoperative hours 8-12(95%CI - 0.85 [- 1.36, - 0.34], I2 = 94%, p = 0.001), postoperative day 1 (95% CI - 0.49 [- 0.85, - 0.14], I2 = 87%, p = 0.006), and postoperative day 2 (95% CI - 0.28 [- 0.51, -0.05], I2 = 72%, p = 0.02); there was no significant difference at postoperative day 3 or discharge (95% CI - 0.14 [- 0.33, 0.05], I2 = 0%, p = 0.14). Combination treatment resulted in reduced dynamic pain scores at postoperative hours 8-12 (95%CI - 0.52 [- 0.92, - 0.12], I2 = 86%, p = 0.01) and postoperative day 1(95% CI - 0.49 [- 0.87, - 0.11], I2 = 88%, p = 0.01). There was no difference between postoperative day 2(95% CI - 0.29 [- 0.63, 0.05], I2 = 80%, p = 0.09), postoperative day 3 or discharge (95% CI - 0.45 [- 0.92, 0.02], I2 = 83%, p = 0.06). In addition, it strongly reduced postoperative opioid consumption within 24 H (95% CI - 0.76 [- 1.13, - 0.39], I2 = 85%, p < 0.00001), 24-48 H (95% CI - 0.43 [- 0.85, - 0.01], I2 = 83%, p = 0.04), and total opioid use (95% CI - 0.64 [- 1.07, - 0.22], I2 = 86%, p = 0.003). Although IPACK supplementation improved timed up and go test and walking distance at postoperative day 2, there was no statistically significant difference at other time periods or obvious improvement in knee range of motion and quadriceps strength. IPACK block supplementation could shorten the length of stay (LOS) (95% CI - 0.40 [- 0.64, - 0.15], I2 = 70%, p = 0.001) and improve patient satisfaction (95% CI 0.43 [0.01, 0.84], I2 = 87%, p = 0.04).

CONCLUSION

Based on these results, IPACK supplementation, in addition to standard postoperative analgesia, can be used effectively and safely to relieve early postoperative pain after total knee arthroplasty.

Does the Addition of iPACK Block to Adductor Canal Block Provide Improved Analgesic Effect in Total Knee Arthroplasty? A Systematic Review and Meta-Analysis

The interspace between popliteal artery and the capsule of posterior knee (iPACK) block was proposed in recent years to relieve posterior knee pain. Since adductor canal block (ACB) and iPACK involve different branches of the sensory nerves, it is theoretically feasible to combine iPACK block and ACB to relief pain after total knee arthroplasty (TKA). We aim to validate the efficacy of adding iPACK block to ACB in the setting of a multimodal pain management protocol following TKA. A comprehensive literature review on Web of Science, Embase, the Cochrane Library, and PubMed was performed. Eight studies (N = 1,056) that compared the efficacy of iPACK block + ACB with ACB alone were included. Primary outcomes consisted of Visual Analogue Scale (VAS) score at rest or during activity at various time points. Secondary outcomes include opioids consumption, walking distance, and length of hospital stay (LOS). Compared to ACB alone, VAS scores at rest (standardized mean difference [SMD]: -1.18; 95% confidence interval [CI]: -2.05 to -0.30) and during activity (SMD: -0.26; 95% CI: -0.49 to -0.03) on the day of surgery were lower in the iPACK block + ACB group. However, the difference did not reach the minimal clinically important difference. Opioids consumption at postoperative 24 hours was lower in the iPACK + ACB group (SMD: -0.295; 95% CI: -0.543 to -0.048). VAS score on postoperative day (POD) 1 and POD2, opioids consumption from 24 to 48 hours, walking distance, and LOS were not different. In conclusion, the addition of iPACK block to ACB in a multimodal pain management protocol can effectively reduce opioids consumption in the early postoperative period. This is a level III, meta-analysis study.

Minimum effective volume of ropivacaine for ultrasound-guided adductor canal + IPACK block in total knee arthroplasty: A double-blind, randomized dose-finding trial

BACKGROUND

Our previous study reported that when a respective 20 mL of ropivacaine was used for adductor canal block (ACB) combined with infiltration between the popliteal artery and capsule of the posterior knee (IPACK) block for patients undergoing total knee arthroplasty (TKA), the minimum concentration of 0.275% could provide successful block in almost all patients. Based on the results, the primary objective of this study was to investigate the minimum effective volume (MEV₉₀, defined as the volume which can provide successful block in 90% of patients) of ACB + IPACK block.

METHODS

This double-blind, randomized dose-finding trial was based on a biased coin up-and-down sequential design, where the volume of ropivacaine administered to a given patient depended on the previous patient's response. The first patient received 15 mL of 0.275% ropivacaine for ACB and again for IPACK. If the block failed, the next subject received a 1 mL higher volume for ACB and IPACK, respectively; otherwise, the next subject received either a 1 mL lower volume (probability of 0.11) or the same volume (probability of 0.89). The primary outcome was whether the block was successful. Block success was defined as the patient did not suffer significant pain and did not receive rescue analgesia within 6 h after surgery. Then the MEV₉₀ was estimated by isotonic regression.

RESULTS

Based on analysis of 53 patients, the MEV₉₀ was 17.99 mL (95% CI 17.47-18.61 mL), MEV₉₅ was 18.48 mL (95% CI 17.45-18.98 mL) and MEV₉₉ was 18.90 mL (95% CI 17.38-19.07 mL). Patients whose blocks succeeded had significantly lower NRS pain scores, lower morphine consumption, and shorter hospitalization.

CONCLUSION

0.275% ropivacaine in 17.99 mL respectively can provide successful ACB + IPACK block in 90% of patients undergoing TKA. The minimum effective volume (MEV₉₀) of ACB + IPACK block was 17.99 mL.

Adductor Canal Block Combined with Interspace between the Popliteal Artery and Capsule of the Knee (iPACK) versus Periarticular Injection for Total Knee Arthroplasty

BACKGROUND

The combination of the adductor canal block (ACB) and the infiltration of anesthetic solution into the interspace between the popliteal artery and capsule of the knee (iPACK) has become increasingly used to augment rapid recovery protocols in total knee arthroplasty (TKA). However, its efficacy in comparison with periarticular anesthetic injection (PAI) alone has yet to be evaluated. Hence, we conducted a retrospective study to compare PAI and ACB + iPACK for controlling pain after TKA.

METHODS

Propensity scores, incorporating American Society of Anesthesiologists scores, body mass index, age, and sex, were used to match the ACB + iPACK group with the PAI group. All patients received the identical surgical technique and postoperative care. Outcome measures were visual analog scale (VAS) for pain, morphine consumption, knee flexion angle, straight leg raising (SLR), postoperative nausea vomiting (PONV), and length of stay (LOS) after the surgery.

RESULTS

After matching by propensity score, there were 49 patients with comparable demographic data in each group. The VAS and morphine requirements of the PAI and ACB + iPACK groups were not different during the first 48 hours after TKA. At 72 hours postoperatively, the VAS of the ACB + iPACK was 0.97 higher than that of the PAI group (p = 0.020). Knee flexion angle, SLR, PONV, and LOS were not significantly different between groups. No procedure-related complications were identified in either group.

CONCLUSIONS

The anesthesiologist-administered ACB + iPACK was as effective as surgeon-administered PAI in controlling pain in the first 48 hours after TKA. However, the ACB + iPACK group had higher intensity of pain than did the PAI group at 72 hours after TKA.

Analgesic efficacy of adding the IPACK block to multimodal analgesia protocol for primary total knee arthroplasty: a meta-analysis of randomized controlled trials

BACKGROUND

Total knee arthroplasty (TKA) is a standard treatment for end-stage degenerative knee disease. Most patients will experience moderate-to-severe postoperative knee pain, significantly affecting rehabilitation. However, controversy remains regarding the efficacy of adding the interspace between the popliteal artery and capsule of the knee (IPACK) into multimodal analgesia protocol.

METHODS

PubMed, Medline, Embase, Cochrane Library, and other databases were searched from inception to February 1, 2021. Studies comparing patients receiving IPACK to patients not receiving IPACK were included. The primary outcome was the ambulation pain score on a visual analogue scale (VAS) of 0-10. Secondary outcomes included pain score at rest, morphine usage, functional recovery, clinical outcomes, and complications.

RESULTS

Thirteen RCTs involving 1347 knees were included. IPACK was associated with lower ambulation pain scores (weight mean difference [WMD] - 0.49, 95% confidence interval [CI] - 0.72 to - 0.26). The benefits were observed from 2 to 4 h, 6 to 12 h, and beyond one week. IPACK also significantly reduced rest pain scores (WMD - 0.49, 95% CI - 0.74 to - 0.24), and the benefits were observed from 6 to 12 h and beyond one week. IPACK reduced the overall morphine consumption (WMD - 2.56, 95% CI - 4.63 to - 0.49). Subgroup analysis found reduced oral morphine consumption from 24 to 48 h (WMD - 2.98, 95% CI - 5.71 to - 0.24) and reduced rate of morphine requirement from 12 to 24 h (relative risk [RR] = 0.51, 95% CI 0.31 to 0.83). Functional recovery outcomes regarding ambulation distances (on the second postoperative day [POD2]) (WMD = 1.74, 95% CI 0.34 to 3.15) and quadriceps muscle strength (at 0 degree) (WMD = 0.41, 95% CI 0.04 to 0.77) favored IPACK. And IPACK reduced the rate of sleep disturbance (on POD 1) (RR = 0.39, 95% CI 0.19 to 0.81). There was no significant difference in the other outcomes.

CONCLUSIONS

Moderate-level evidence confirmed that IPACK was related to better results in pain scores, morphine usage, and functional recovery without increasing the risk of complications.

REGISTRATION

CRD42021252156.

Development of Enhanced Recovery After Surgery (ERAS) protocols in veterinary medicine through a one-health approach: the role of anesthesia and locoregional techniques

Enhanced Recovery After Surgery (ERAS) is a new and emerging concept in human medicine that involves rethinking the preoperative, intraoperative, and postoperative periods. The ultimate, overarching aim is to improve patient outcome following surgery and, thus, return to a normal daily routine as soon as possible. The development and implementation of locoregional anesthetic techniques in humans is one of the key elements driving these protocols. In veterinary medicine, we are no exception: the rapidly growing interest, development, and refinement of these techniques in our veterinary species is changing the way we think of anesthesia and analgesia. The potential real benefits are yet to be determined, as this concept is implemented into our veterinary hospitals in general, and our surgical patients in particular, in a more systematic and routine way. In this article, we will introduce the reader to the concept of ERAS protocols and the role of regional anesthesia in some common surgical procedures.

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.

Minimum effective concentration of ropivacaine for ultrasound-guided adductor canal + IPACK block in total knee arthroplasty

OBJECTIVE

This study aimed to investigate the minimum effective concentration (MEC_90, defined as effective in 90% of patients) of ropivacaine during the combined procedure of adductor canal block (ACB) and infiltration between the popliteal artery and capsule of the posterior knee (IPACK) block for patients undergoing total knee arthroplasty.

METHODS

This double-blind, randomized dose-finding trial was based on a biased coin up-and-down sequential design, where the concentration of ropivacaine administered to a given patient depended on the previous patient's response. Before surgery, the first patient received 20 mL of 0.2% ropivacaine for ACB and again for IPACK. If the block failed, the next subject received a 0.025% higher ropivacaine concentration; otherwise, the next subject received either a 0.025% smaller dose (probability of 0.11) or the same dose (probability of 0.89). The primary outcome was whether the block was successful. Block success was defined as the patient did not suffer significant pain and did not receive rescue analgesia within 6 h after surgery. MEC₉₀ was estimated by isotonic regression, and the 95% confidence interval (CI) was calculated by bootstrapping. Secondary outcomes were numerical rating scale (NRS) pain scores at postoperative 24 h and 48 h, postoperative morphine consumption, and time to hospital discharge. Secondary outcomes were compared between patients whose blocks succeeded with those which failed.

RESULTS

Based on analysis of 52 patients, the MEC₉₀ was 0.247% (95% CI 0.227-0.271%), MEC₉₅ was 0.260% (95% CI 0.244-0.282%) and MEC₉₉ was 0.272% (95% CI 0.260-0.291%). In contrast, four of nine trials in a recent systematic review reported ropivacaine concentrations below 0.247%. Patients whose blocks succeeded (n = 45) had significantly lower NRS pain scores, lower morphine consumption, and shorter hospitalization than patients whose blocks failed (n = 7).

CONCLUSIONS

Our small trial suggests that 0.247% ropivacaine in 20 mL respectively can provide successful ACB + IPACK block in 90% of patients. However, given that many published trials have used lower concentrations, our findings should be verified in larger studies.

iPACK block (local anesthetic infiltration of the interspace between the popliteal artery and the posterior knee capsule) added to the adductor canal blocks versus the adductor canal blocks in the pain management after total knee arthroplasty: a systematic review and meta-analysis

Background

Several studies have suggested that the addition of iPACK block (the popliteal artery and the posterior knee capsule have been given interspace local anesthetic infiltration) might get better analgesia than adductor canal block (ACB) only after total knee arthroplasty (TKA). This paper compiles all available evidence on the effect of two analgesia regimens (ACB and iPACK + ACB) involving all sides.

Methods

We searched in eight major databases for all clinical trials discussing the effect of two analgesia regimens after TKA. Statistical analyses were conducted by Stata and RevMan Software. In addition, we performed GOSH analysis, subgroup analysis, meta-regression analysis to study the source of heterogeneity. Publication bias was checked using Egger’s test. Trim-and-fill analysis was applied in terms of sensitivity analysis of the results.

Results

There are fourteen eligible studies for our meta-analysis. There are significant differences between the two groups in VAS score at rest and with activity, and the VAS scores were lower in the ACB + iPACK Group (VAS scores at rest: 95%CI [− 0.96, − 0.53], P < 0.00001. VAS scores with activity: 95%CI [− 0.79, − 0.43], P < 0.00001). A differential was discovered to support the ACB + iPACK Group when comparing the two groups on postoperative cumulative morphine consumption (95%CI: [− 0.52, − 0.14], P: 0.0007). The patients in the group of ACB + iPACK performed better in the postoperative range of knee movement (95%CI: [5.18, 10.21], P < 0.00001) and walking distance (95%CI: [0.15, 0.41], P < 0.00001). There were significant differences between the patients in the ACB + iPACK Group and ACB Group on the TUG test of POD1 and POD2. We found that patients' hospital stays in the ACB + iPACK Group were significantly shorter than in the ACB Group (95%CI: [− 0.78, − 0.16], P: 0.003). No difference was found between the patients in the ACB + iPACK Group and ACB Group on postoperative quadriceps muscle strength and the incidence of PONV.

Conclusion

The addition of iPACK lowers postoperative VAS scores, cumulative morphine consumption, and hospital stays. Meanwhile, the addition of iPACK improves postoperative patients’ activity performance without extra side effects. iPACK combined with ACB proves to be a suitable pain management technique after TKA.

No Benefits of Adding Dexmedetomidine, Ketamine, Dexamethasone and Nerve Blocks to an Established Multimodal Analgesic Regimen after Total Knee Arthroplasty

BACKGROUND.

An optimal opioid-sparing multimodal analgesic regimen to treat severe pain can enhance recovery after total knee arthroplasty. We hypothesized that adding 5 recently described IV and regional interventions to multimodal analgesic regimen can further reduce opioid consumption.

METHODS.

In a double-blinded fashion, seventy-eight patients undergoing elective total knee arthroplasty were randomized to either (1) a control group (n=39) that received spinal anesthesia with intrathecal morphine, periarticular local anesthesia infiltration, IV dexamethasone and a single injection adductor canal block or (2) a study group (n=39) that received the same set of analgesic treatments plus 5 additional interventions - local anesthetic infiltration between the popliteal artery and capsule of the posterior knee, intraoperative IV dexmedetomidine and ketamine, and postoperatively, 1 additional IV dexamethasone bolus, and 2 additional adductor canal block injections. The primary outcome measure was 24-hour cumulative opioid consumption after surgery and secondary outcomes were other analgesic, patient recovery and functional outcomes and adverse events.

RESULTS.

Opioid consumption was not different between groups at 24 hours (oral morphine equivalents, mean ± SD), study: 23.7 ± 18.0 mg vs. control: 29.3 ± 18.7 mg; mean difference [95% CI], -5.6 mg [-2.7, 13.9]; P = 0.189) and all other time points after surgery. There were no major differences in pain scores, quality of recovery, or time to reach rehabilitation milestones. Hypotensive episodes occurred more frequently in the study group (25/39 (64.1%) vs. 13/39 (33.3%), p= 0.010).

CONCLUSIONS.

In the presence of periarticular local anesthesia infiltration, intrathecal morphine, single shot adductor canal block and dexamethasone, the addition of 5 analgesic interventions - local anesthetic infiltration between the popliteal artery and capsule of the posterior knee, IV dexmedetomidine, IV ketamine, an additional IV dexamethasone dose and repeated adductor canal block injections - failed to further reduce opioid consumption, pain scores or improve functional outcomes after total knee arthroplasty.

The effect of continuous adductor canal block combined with distal interspace between the popliteal artery and capsule of the posterior knee block for total knee arthroplasty: a randomized, double-blind, controlled trial

BACKGROUND

The optimal analgesia for total knee arthroplasty (TKA) requires excellent analgesia while preserving muscle strength. This study aimed to determine the hypothesis that continuous adductor canal block (CACB) combined with the distal interspace between the popliteal artery and the posterior capsule of the knee (IPACK) block could effectively alleviate the pain of the posterior knee, decrease opioids consumption, and promote early recovery and discharge.

METHODS

Patients undergoing unilateral, primary TKA were allocated into group CACB+SHAM (receiving CACB plus sham block) or group CACB+IPACK (receiving CACB plus IPACK block). The primary outcome was cumulative opioid consumption. Secondary outcomes included the incidence of postoperative pain originated from the posterior knee, visual analogue scale (VAS) score, range of motion, ambulation distance, and satisfaction for pain management.

RESULTS

The incidence of moderate-severe pain of the posterior knee was lower in group CACB+IPACK than that of the group CACB+SHAM at 4 hours (17.1% vs. 42.8%; p = 0.019), 8 hours (11.4% vs. 45.7%; p = 0.001), and 24 hours (11.4% vs. 34.3%; p = 0.046) after TKA. The VAS scores of the posterior knee were lower in group CACB+IPACK than that of the group CACB+SHAM at 4 hours [2 (2) vs. 3 (2-4); p = 0.000], 8 hours [1 (1, 2) vs. 3 (2-4); p = 0.001], and 24 hours [1(0-2) vs. 2 (1-4); p = 0.002] after TKA. The overall VAS scores were lower in group CACB+IPACK than that of the group CACB+SHAM at 4 hours [3 (2, 3) vs. 3 (3, 4); p = 0.013] and 8 hours [2 (2, 3) vs. 3 (2-4); p = 0.032] at rest and 4 hours [3 (3, 4) vs. 4 (4, 5); p = 0.001], 8 hours [3 (2-4) vs. 4 (3-5); p = 0.000], 24 hours [2 (2, 3) vs. 3 (2-4); p = 0.001] during active flexion after TKA. The range of motion (59.11 ± 3.90 vs. 53.83 ± 5.86; p = 0.000) and ambulation distance (44.60 ± 4.87 vs. 40.83 ± 6.65; p = 0.009) were superior in group CACB+IPACK than that of the group CACB+SHAM in postoperative day 1. The satisfaction for pain management was higher in group CACB+IPACK than that of the group CACB+SHAM [9 (8, 9) vs. 8 (7-9); p = 0.024]. There was no difference in term of cumulative opioids consumption between group CACB+IPACK and group CACB+SHAM [120(84-135) vs. 120(75-135); p = 0.835].

CONCLUSION

The combination of CACB and distal IPACK block could decrease the incidences of moderate-severe posterior knee pain, improve the postoperative pain over the first 24 hours after TKA, as well as promoting recovery of motor function. However, the opioids consumption was not decreased by adding distal IPACK to CACB.

TRIAL REGISTRATION

This study was registered at Chinese Clinical Trial Registry ( ChiCTR2200059139 ; registration date: 26/04/2022; enrollment date: 16/11/2020; http://www.chictr.org.cn ).

Adductor Canal Blocks With Bupivacaine and Magnesium After Same-day Discharge Total Knee Arthroplasty Improve Postoperative Pain Relief and Decrease Opioid Consumption: A Prospective Randomized Controlled Trial

OBJECTIVES

Adequate pain management is a critical component of facilitating same-day discharge for total knee arthroplasty (TKA). Adductor canal blocks (ACB) have been shown to be an effective technique for managing pain after TKA. The objective of this study was to investigate the impact of adding magnesium to local anesthetic in ACB on postoperative pain, opioid consumption, nausea, and overall patient satisfaction.

MATERIALS AND METHODS

A sample of 119 adults undergoing elective unilateral TKA were included. Patients were randomly assigned to receive ACB with magnesium and bupivacaine (n=56) or with bupivacaine only (n=63). Primary outcomes were total opioid consumption in the first 48 hours after surgery and pain scores. Secondary outcomes were the incidence of nausea in the first 48 hours after surgery and total overall satisfaction.

RESULTS

Opioid consumption decreased significantly in the Mg group compared with the no-Mg group over the first 24 hours (33.2±3.0 vs. 21.3±2.4, P=0.003), the second 24 hours (35.4±2.7 vs. 27.3±2.3, P=0.026), and the first 48 hours total after surgery (68.6±5.1 vs. 48.6±4.3, P=0.004). Pain scores were reduced in the Mg group (24 h: 5.1±2.3 vs. 3.5±2.0, P=0.000; 48 h: 5.1±1.6 vs. 3.9±1.6, P=0.000). Secondary outcomes showed no difference in the incidence of nausea over the first 48 hours and overall satisfaction.

CONCLUSION

The addition of magnesium to local anesthetic in ACB decreases pain scores and opioid consumption, without increasing nausea, when compared with ACB with local anesthetic alone.

Peripheral Nerve Blockade for Medial Patellofemoral Ligament Reconstruction in Pediatric Patients: The Addition of a Proximal Single-Injection Sciatic Nerve Block Provides Improved Analgesia

Purpose

We tested the hypothesis that the addition of a single-injection proximal sciatic nerve block to an adductor canal block would significantly reduce pain scores and opioid requirements compared to a group of patients that received only an adductor canal or femoral nerve block for medial patellofemoral ligament reconstruction in pediatric patients. The primary end-point is the number of patients achieving a Patient Acceptable Symptom State (PASS) (pain score less than four) for the entire 24-hour postoperative period in patients with and without a proximal sciatic block.

Patients and Methods

This is a retrospective cohort study of 144 consecutive pediatric patients, ages 10 to 18 years, undergoing medial patellofemoral ligament reconstruction with peripheral nerve blockade for postoperative analgesia from 2016–2020 at a pediatric orthopedics children’s hospital. Patients were divided into 2 cohorts with and without a proximal sciatic nerve block: group A/F: adductor canal or femoral CPNB and group AS: adductor canal CPNB and a proximal single-injection sciatic nerve block.

Results

There was strong evidence for an increase in the number of patients who reported a pain score less than four for the entire 24-hour postoperative period in the group that received the additional proximal sciatic block. (PASS: A/F 13/62 (21%) vs AS 43/82 (52%), p<0.001) There was strong evidence for a reduction in mean and maximum pain scores and opioid requirements in the first 24-hours after surgery in the proximal sciatic group.

Conclusion

The addition of a proximal sciatic nerve block was associated with significantly reduced mean and maximum pain scores and opioid requirements after medial patellofemoral ligament reconstruction in pediatric patients and supports a randomized clinical trial to confirm these findings. Based on the results of this study we recommend the addition of a proximal sciatic nerve block, anterior or posterior, to an adductor canal block to provide improved analgesia and reduced opioid requirements in the 24-hours after MPFLR in pediatric patients.

Optimal location for continuous catheter analgesia among the femoral triangle, proximal, or distal adductor canal after total knee arthroplasty: a randomized double-blind controlled trial

Background

Pain management after total knee arthroplasty is essential to improve early mobilization, rehabilitation, and recovery. Continuous adductor canal (AC) block provides postoperative analgesia while preserving quadriceps strength. However, there have been inconsistencies regarding the optimal location for continuous catheter block. We compared continuous femoral triangle, proximal AC, and distal AC blocks for postoperative analgesia after total knee arthroplasty.

Methods

Patients undergoing unilateral total knee arthroplasty were randomly assigned to three groups: femoral triangle, proximal AC, or distal AC. The surgeon performed periarticular local anesthetic infiltration. After surgery, an ultrasound-guided perineural catheter insertion procedure was performed. The primary endpoint was pain scores at rest in the morning on the first postoperative day. Secondary endpoints included pain scores at rest and during activity at other time points, quadriceps strength, and opioid consumption.

Results

Ninety-five patients, 32 in the femoral triangle group, 31 in the proximal AC group, and 32 in the distal AC group, completed the study. Analysis of the primary outcome showed no significant difference in pain scores among groups. Secondary outcomes showed significantly lower pain scores at rest and during activity in the distal AC group than in the femoral triangle and proximal AC groups in the morning of the second postoperative day. Quadriceps strength and opioid consumption did not differ among groups.

Conclusions

Continuous femoral triangle, proximal AC, and distal AC blocks in the setting of periarticular local anesthetic infiltration provide comparable postoperative analgesia after total knee arthroplasty.

Trial registration number

NCT04206150.

Adductor Canal Block Combined With IPACK Block for Postoperative Analgesia and Function Recovery Following Total Knee Arthroplasty: A Prospective, Double-Blind, Randomized Controlled Study

BACKGROUND

This study aimed to explore the analgesic effect among adductor canal block (ACB) combined with infiltration between the popliteal artery and the capsule of the posterior knee (IPACK) block, ACB, and IPACK block following total knee arthroplasty (TKA).

METHODS

One hundred twenty patients were randomly allocated into 3 groups including group A (ACB + IPACK block), group B (ACB), and group C (IPACK block). The primary outcome was postoperative pain score. The secondary outcome was opioid consumption. Other outcomes included functional evaluation and postoperative complications.

RESULTS

Group A showed the lowest pain scores within 8 hours at rest and with knee maximum flexion (P < .001). From 12 to 24 hours, group C showed the highest pain scores, while no significant difference was found between group A and group B. No significant difference was found among the 3 groups 24 hours postoperatively. Group C showed the most opioid consumption within the first 24 hours and during the hospitalization, while no significant difference was found between group A and group B. No significant difference was found among the 3 groups including function evaluation and postoperative complications.

CONCLUSION

ACB + IPACK block can improve early analgesia when compared with ACB. However, the small statistical benefit to the addition of IPACK block to ACB may be unlikely to be clinically significant. Further studies may focus on patient selection and how to prolong the effect of IPACK block.

Role of regional anesthesia in Enhanced Recovery After Surgery (ERAS) protocols

PURPOSE OF REVIEW

Enhanced Recovery After Surgery (ERAS) protocols and interventional locoregional anesthesia (LRA) techniques continuously evolve. This review outlines the latest recommendations for the use of regional anesthesia in ERAS protocols and emerging interventional analgesia techniques.

RECENT FINDINGS

Research in ultrasound-guided regional anesthesia has led to a refinement of the traditional techniques and the introduction of a number of new approaches to complement ERAS strategies. The efficacy and versatility of LRA enable its use in an increasing number of ERAS indications.

SUMMARY

The implementation of ERAS protocols in different surgical procedures reduces overall complications and recovery time. Multimodal analgesia strategies with regional anesthesia techniques are some of the key interventions contributing to the improvement in postoperative outcomes.

Postoperative pain: a review of emerging therapeutic options

INTRODUCTION

Postoperative pain is often managed by opioid medications, even though they carry a risk of adverse effects such as vomiting, constipation, sedation, respiratory depression and physical dependence. Furthermore, opioid use in the healthcare setting has likely contributed to the epidemic. However, the mismanagement of postoperative pain can result in delayed recovery time, impaired physical function, increased risk of morbidity and mortality, chronic pain, and higher healthcare costs.

AREAS COVERED

This review explores emerging therapeutic options and strategies in the management of acute postoperative pain and focuses on opioid-sparing, multimodal analgesia. This includes regional anesthetic techniques, non opioid pharmacotherapy, novel opioids and non-pharmacologic therapy. We have also discussed examples of novel analgesics and formulations which have potential benefits in reducing postoperative pain and opioid use after surgery.

EXPERT OPINION

The development of novel regional anesthesia techniques allows for opioid minimization in increasing number of surgical procedures. This synergizes with the availability of novel non-opioid analgesic adjucts. In addition, several novel opioid drugs have been developed which may be pathway selective and associated with less adverse effect than conventional opioids.

Ultrasound-guided genicular nerve blocks following total knee arthroplasty: a randomized, double-blind, placebo-controlled trial

INTRODUCTION

Local anesthetic blockade of the genicular nerves, known targets of radiofrequency ablative techniques for knee pain, has not previously been studied in a randomized controlled trial evaluating acute pain after knee arthroplasty. We hypothesized that genicular nerve blockade added to an existing block regimen in total knee arthroplasty would result in a reduction in 24 hours opioid consumption.

METHODS

Patients (American Society of Anesthesiologists 1-3, aged 18-85 years) undergoing primary total knee arthroplasty were randomized to receive single-injection nerve blocks of the superolateral, superomedial, and inferomedial genicular nerves with injectate (15 mL 0.25% bupivacaine and 2 mg dexamethasone or 15 mL saline placebo). All subjects received a standard oral analgesic regimen, spinal anesthetic with 12.5 mg isobaric bupivacaine, infiltration between the popliteal artery and capsule of the knee with 0.2% ropivacaine, and postoperative adductor canal perineural infusion with 0.2% ropivacaine. The primary outcome was 24 hours opioid consumption (measured in morphine milliequivalents).

RESULTS

Forty (40) subjects were enrolled. Opioid consumption at 24 hours was significantly lower in the BLOCK group compared with the SHAM group (23±20 vs 58±35, p<0.001), and this difference remained significant at 48 hours (50±40 vs 98±56, p=0.004). Pain scores were reduced in the BLOCK group at time 6 hours (2.6±1.9 vs 4.3±2.2, p=0.012), but were otherwise similar at remaining time points. Patient satisfaction at 24 hours and 20 m walk test times were similar between groups.

DISCUSSION

Genicular nerve blockade was associated with a reduction in opioid consumption at 24 hours in primary total knee arthroplasty patients.

TRIAL REGISTRATION NUMBER

NCT03706313.

Analgesia effects of IPACK block added to multimodal analgesia regiments after total knee replacement: A systematic review of the literature and meta-analysis of 5 randomized controlled trials

BACKGROUND

Currently, no meta-analysis exists elucidate the analgesic effect of adding IPACK block to our current multimodal analgesia regimen after total knee replacement (TKR). The purpose of this study is to systematically review the level I evidence in the literature to ascertain whether IPACK block can bring additional analgesic benefits to existing multimodal analgesia regimens.

METHODS

The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Only level I randomized controlled trials (RCTs) were included in our study. The primary outcome was the pain scores with rest and activity. Secondary outcomes included cumulative opioid consumption, cumulative distance ambulated, and length of stay (LOS).

RESULTS

Five RCTs with a total of 467 patients were included. The most important finding in our study was that although IPACK block supplementation improved pain scores at 12 hours with rest or activity after surgery, no such benefit was observed at subsequent time points during the postoperative period. Interestingly, IPACK supplementation did not reduce opioid consumption, especially in the first 24 hours after surgery. Furthermore, other postoperative outcomes, including cumulative distance ambulated and LOS, were also not improved by the addition of an IPACK.

CONCLUSIONS

The addition of an IPACK block to multimodal analgesia regiments does not reduce the postoperative opioid consumption nor improve functional performance. However, it may be an appropriate method to improve immediate analgesic effects after TKR.

Combination of femoral triangle block and infiltration between the popliteal artery and the capsule of the posterior knee (iPACK) versus local infiltration analgesia for analgesia after anterior cruciate ligament reconstruction: a randomized controlled triple-blinded trial

BACKGROUND AND OBJECTIVES

Femoral triangle block and local infiltration analgesia are two effective analgesic techniques after anterior cruciate ligament reconstruction. Recently, the iPACK block (infiltration between the popliteal artery and the capsule of the posterior knee) has been described to relieve posterior knee pain. This randomized controlled triple-blinded trial tested the hypothesis that the combination of femoral triangle block and iPACK provides superior analgesia to local infiltration analgesia after anterior cruciate ligament reconstruction.

METHODS

Sixty patients undergoing anterior cruciate ligament reconstruction received general anesthesia and were randomly allocated to two groups: femoral triangle block and iPACK under ultrasound guidance or local infiltration analgesia. For each group, a total of 160 mg of ropivacaine was injected. Postoperative pain treatment followed a predefined protocol with intravenous morphine patient-controlled analgesia, acetaminophen, and ibuprofen. The primary outcome was cumulative intravenous morphine consumption at 24 hours postoperatively. Secondary pain-related outcomes included pain scores (Numeric Rating Scale out of 10) measured at 2 and 24 hours postoperatively. Functional outcomes, such as range of motion and quadriceps strength, were also recorded at 24 postoperative hours, and at 4 and 8 postoperative months.

RESULTS

Cumulative intravenous morphine consumption at 24 hours postoperatively was significantly reduced in the femoral triangle block and iPACK group (femoral triangle block and iPACK: 9.7 mg (95% CI: 6.7 to 12.7); local infiltration analgesia: 17.0 mg (95% CI: 11.1 to 23.0), p=0.03). Other pain-related and functional-related outcomes were similar between groups.

CONCLUSIONS

The combination of femoral triangle block and iPACK reduces intravenous morphine consumption during the first 24 hours after anterior cruciate ligament reconstruction, when compared with local infiltration analgesia, without effect on other pain-related, early, or late functional-related outcomes.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT03680716).

Infiltration between the popliteal artery and the capsule of the knee (IPACK) block in knee surgery: a narrative review

BACKGROUND

The infiltration between the popliteal artery and the capsule of the knee (IPACK) block has been described as an alternative analgesic strategy for knee pain.

OBJECTIVE

Our aim was to perform a narrative review to examine the place and value that the IPACK block has in comparison to and in conjunction with other regional anesthesia modalities.

EVIDENCE REVIEW

Following an extensive search of electronic databases, we included anatomical studies, letters, comparative observational studies, and non-randomized and randomized controlled trials that examined the IPACK block in relation to surgery on the knee under general or neuraxial anesthesia.

FINDINGS

In all, 35 articles were included. Cadaveric studies demonstrated the potential for injected dye to spread to the nerves responsible for the innervation of the posterior as well as anteromedial and anterolateral aspects of the knee. Of the comparative observational studies (n=15) and non-randomized (n=1) and randomized controlled trials (n=13), 2 and 27 were conducted in the context of anterior cruciate ligament reconstruction and knee replacement surgery, respectively. The role of the IPACK block with each different permutation of regional anesthesia techniques was investigated by a small number of studies. Clinical studies, in the setting of knee replacement surgery, revealed variation in the manner in which the IPACK block was performed, and indicated the possible superiority of distal injection at the level of the femoral condyles for the management of posterior knee pain. Evidence suggested the following: the IPACK block in combination with single shot adductor canal block (ACB) may be beneficial for analgesic and functional outcomes; in conjunction with single shot or continuous ACB, the IPACK block might be superior to local infiltration analgesia (LIA); and functional outcomes may be improved with the supplementation of continuous ACB and LIA with the IPACK block. The IPACK block did not commonly result in the occurrence of foot drop. Relative to tibial nerve block (TNB), the IPACK block reduced the occurrence of foot drop and increased the proportion of patients who were able to be discharged on the third postoperative day.

CONCLUSIONS

The IPACK block was potentially complementary to the ACB and might be preferable to the TNB as a motor-sparing regional anesthesia technique in knee surgery. Definitive recommendations were not reached in the presence of the heterogeneous and limited evidence base.

Does the addition of iPACK to adductor canal block in the presence or absence of periarticular local anesthetic infiltration improve analgesic and functional outcomes following total knee arthroplasty? A systematic review and meta-analysis

BACKGROUND

When combined with adductor canal block (ACB), local anesthetic infiltration between popliteal artery and capsule of knee (iPACK) is purported to improve pain following total knee arthroplasty (TKA). However, the analgesic benefits of adding iPACK to ACB in the setting of surgeon-administered periarticular local infiltration analgesia (LIA) are unclear.

OBJECTIVES

To evaluate the analgesic benefits of adding iPACK to ACB, compared with ACB alone, in the setting of LIA following TKA.

EVIDENCE REVIEW

We conducted a meta-analysis of randomized trials comparing the effects of adding iPACK block to ACB versus ACB alone on pain severity at 6 hours postoperatively in adult patients undergoing TKA. We a priori planned to stratify analysis for use of LIA. Opioid consumption at 24 hours, functional recovery, and iPACK-related complications were secondary outcomes.

FINDINGS

Fourteen trials (1044 patients) were analyzed. For the primary outcome comparison in the presence of LIA (four trials, 273 patients), adding iPACK to ACB did not improve postoperative pain at 6 hours. However, in the absence of LIA (eight trials, 631 patients), adding iPACK to ACB reduced pain by a weighted mean difference (WMD) (95% CI) of -1.33 cm (-1.57 to -1.09) (p<0.00001). For the secondary outcome comparisons in the presence of LIA, adding iPACK to ACB did not improve postoperative pain at all other time points, opioid consumption or functional recovery. In contrast, in the absence of LIA, adding iPACK to ACB reduced pain at 12 hours, and 24 hours by a WMD (95% CI) of -0.98 (-1.79 to -0.17) (p=0.02) and -0.69 (-1.18 to -0.20) (p=0.006), respectively, when compared with ACB alone, but did not reduce opioid consumption. Functional recovery was also improved by a log(odds ratio) (95% CI) of 1.28 (0.45 to 2.11) (p=0.003). No iPACK-related complications were reported.

CONCLUSION

Adding iPACK to ACB in the setting of periarticular LIA does not improve analgesic outcomes following TKA. In the absence of LIA, adding iPACK to ACB reduces pain up to 24 hours and enhances functional recovery. Our findings do not support the addition of iPACK to ACB when LIA is routinely administered.

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

Posterior knee pain after total knee arthroplasty (TKA) is common despite multimodal analgesia and regional anesthesia use. This review included randomized controlled trials (RCTs) comparing analgesic outcomes after inclusion of local anesthetic infiltration between the popliteal artery and capsule of the knee (iPACK) block versus pathways without iPACK. Electronic databases (MEDLINE, Cochrane Library, Web of Science, Scopus) were searched from inception to 10/11/2020. Eligible studies evaluated iPACK use on primary outcomes: opioid consumption and pain scores with movement. Secondary outcomes included rest pain, patient satisfaction, length of stay (LOS), gait distance, knee range of motion (ROM), and complications. Bias and quality were appraised using the Cochrane Risk of Bias tool and Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) guidelines. Eight RCTs (777 patients) were included. iPACK block use demonstrated similar opioid consumption in the PACU (4/7 RCTs) and 24 hours after TKA (5/7 RCTs) compared to without iPACK (moderate-quality GRADE evidence). Additionally, iPACK block use demonstrated lower movement pain scores in PACU (3/5 RCTs) but similar or higher pain scores after 24 hours (5/7 RCTs; low-quality GRADE evidence). Studies consistently reported no difference in gait distance (4/4 RCTs) or complications (7/7 RCTs) between treatment arms (high-quality GRADE evidence), although differing effect estimates were observed with resting pain, satisfaction, LOS, and knee ROM. This review provides a foundation of knowledge on iPACK efficacy. While evidence does not currently support widespread inclusion of iPACK within enhanced recovery pathways for TKA, limitations suggest further study is warranted.

The analgesic efficacy of iPACK after knee surgery: A systematic review and meta-analysis with trial sequential analysis

STUDY OBJECTIVE

The novel infiltration between the popliteal artery and the capsule of the posterior knee (iPACK) has been described to relieve posterior knee pain after knee surgery. The study objective is to determine whether iPACK provides analgesia after knee surgery when compared with a control group.

DESIGN

Systematic review, meta-analysis and trial sequential analysis.

SETTING

Operating room, postoperative recovery area and ward, up to 24 postoperative hours.

PATIENTS

Patients scheduled for knee surgery under general or spinal anaesthesia.

INTERVENTIONS

We searched five electronic databases for randomized controlled trials comparing iPACK with a control group.

MEASUREMENTS

The primary outcome was rest pain score scores on a visual analogue scale (VAS) of 0-10 at 12 h postoperatively, analysed according to the nature of surgery (total knee arthroplasty vs. anterior cruciate ligament reconstruction) and the use of multimodal analgesia. Secondary outcomes included rest and dynamic pain scores, intravenous morphine-equivalent consumption at 2 h and 24 h, and functional outcomes including ambulation distance and range of motion at discharge.

MAIN RESULTS

Six trials involving 687 patients were included, all of which received total knee arthroplasty only. When compared with a control group, iPACK significantly reduced rest pain scores at 12 h, with a mean difference (95% CI) of -1.0 (-1.5 to -0.5), I² = 93%, p = 0.0003, without subgroup differences for postoperative multimodal analgesia (p = 0.15). Secondary pain outcomes were inconsistently improved with iPACK. Functional outcomes were either similar between groups or had clinically unimportant differences. The overall quality of evidence was moderate.

CONCLUSIONS

There is moderate level evidence that iPACK might provide analgesia for posterior pain after total knee arthroplasty when compared with a control group at 12 h, but was not associated with any other meaningful benefits. Based on these results, there is currently limited evidence supporting the use of iPACK as a complement to adductor canal block for analgesia after total knee arthroplasty.