Efficacy of Adductor Canal Block Combined With Additional Analgesic Methods for Postoperative Analgesia in Total Knee Arthroplasty: A Prospective, Double-Blind, Randomized Controlled Study

Efficacy of adductor canal and popliteal plexus block combined with local anesthetic injection in the interspace between the popliteal artery and posterior capsule of the knee and local infiltrative analgesia for postoperative pain and functional outcome after total knee arthroplasty: A randomized controlled study

BACKGROUND

Adductor canal block and periarticular infiltration analgesia (PIA) have been shown to relieve pain in total knee arthroplasty (TKA) effectively. However, their analgesic effectiveness has some limitations. Thus, we considered a novel blocking site that could achieve analgesia without affecting the muscle strength of the lower limbs.

METHODS

Seventy-two patients undergoing primary unilateral total knee arthroplasty were randomized into two groups. One group was treated with adductor canal and popliteal plexus (APB) combined with interspace between the popliteal artery and posterior capsule of the knee (iPACK) and local infiltration anesthesia (LIA) and the other was treated with PIA. The primary outcomes included postoperative pain, as assessed by the visual analog scale (VAS), and the consumption of oral tramadol. Secondary outcomes included functional recovery and daily ambulation distance. Tertiary outcomes included postoperative adverse effects.

RESULTS

The APB group had lower VAS scores after surgery at rest and during motion. Compared with the PIA group, the walking distance of the APB group on the second day was greater. The muscle strength of the APB group was lower than that of the PIA group at the early stage. Patients in the APB group also consumed less tramadol than those in the PIA group. There was no difference in the incidence of adverse events between the two groups.

CONCLUSIONS

APB combined with iPACK and LIA is a novel block for TKA, and it can reduce postoperative pain sooner after TKA without affecting postoperative functional recovery or increasing complications.

Comparing Different Multimodal Analgesia Protocols for Primary Total Knee Arthroplasty-A Retrospective Cohort Analysis

Background: Several local regional anesthesia regimes have been described in the literature to reduce post-surgical pain following total knee arthroplasty (TKA), but it is unclear which regime has the best analgetic effect combined with the best motor function. The aim of this study was to determine if patients with infiltration between the popliteal artery and capsule of the posterior knee (IPACK) combined with an adductor canal block (SACB) had less pain, better motor function, and less opioid consumption after TKA than patients with a femoral nerve block (FNB) combined with a popliteal sciatic nerve block (PSB). Methods: In a retrospective cohort analysis, 342 patients following primary TKA were examined; 175 patients were treated with an IPACK combined with a SACB, and 167 patients with a femoral FNB combined with a PSB. The outcome parameters postoperative pain (visual analogue scale (VAS) for mobilization and at rest, functional recovery, opioid consumption, hospital discharge, and complications were analyzed and compared between both groups. Results: The IPACK/SACB group had a higher postoperative need for opioids despite higher doses of ropivacaine compared to the FNB/PSB group, accompanied by higher VAS scores. Patients' satisfaction was equal between the groups. Both groups showed comparable mobilization rates and walking distances following TKA. Conclusions: IPACK/SACB showed equal results compared to FNB/PSB for mobilization rates and patients' satisfaction following TKA without a reduction in opioid consumption.

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.

Characterizing patient factors, perioperative interventions, and outcomes associated with inpatients falls after total knee arthroplasty

INTRODUCTION

Mechanical falls represent a potential adverse event after total knee arthroplasty (TKA) and may introduce further injury and delay postoperative recovery. This study aimed to identify patient characteristics associated with inpatient falls, to determine the impact of inpatient falls on surgical outcomes following TKA, and to describe the relationship between tourniquet and/or adductor canal block (ACB) use and fall rates.

METHODS

Patients undergoing primary, elective TKA at a single institution between 2018 and 2022 were retrospectively analyzed. Patients were stratified into groups based on whether they sustained a postoperative inpatient fall or not. Perioperative characteristics, lengths of stay (LOS), rates of 90-day readmissions, and revisions were compared, and fall characteristics were described. Subanalysis was conducted comparing fall incidence based on tourniquet and/or ACB use.

RESULTS

In total 6472 patients were included with 39 (0.6%) sustaining falls. Falls most commonly occurred on postoperative days one (43.6%) and two (30.8%), and were most commonly due to loss of balance (41.9%) or buckling (35.5%). Six (15.4%) fall patients sustained minor injuries, and one (2.6%) sustained major injury (malleolar fracture requiring non-operative orthopaedic management). The LOS (3.0 ± 1.5 vs 2.3 ± 1.5 days, p = 0.002) and all-cause revision rates at latest follow-up (10.3% vs. 2.0%, p = 0.008) were significantly higher in the fall group. Falls were comparable across subgroups based on tourniquet and/or ACB use (p = 0.429).

CONCLUSION

Patients who fell had a longer LOS and higher revision rate postoperatively. Rates of inpatient falls were comparable regardless of tourniquet and/or ACB use. Concern for inpatient falls should not influence surgeons when considering the use of tourniquets and/or ACBs, though well-designed, large-volume, prospective randomized studies are warranted to better understand this relationship.

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

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.

Effects of magnesium sulfate on periarticular infiltration analgesia in total knee arthroplasty: a prospective, double-blind, randomized controlled trial

BACKGROUND

To investigate whether adding magnesium sulfate to a periarticular infiltration analgesia (PIA) cocktail could improve pain control and functional outcomes in patients undergoing total knee arthroplasty (TKA).

METHODS

Ninety patients were randomly assigned to the magnesium sulfate and control groups, with 45 patients in each group. In the magnesium sulfate group, patients were given a periarticular infusion of a cocktail of analgesics consisting of epinephrine, ropivacaine, magnesium sulfate, and dexamethasone. The control group received no magnesium sulfate. The primary outcomes consisted of visual analogue scale (VAS) pain scores, postoperative morphine hydrochloride consumption for rescue analgesia, and time to first rescue analgesia. Secondary outcomes were postoperative inflammatory biomarkers (IL-6 and CRP), postoperative length of stay, and knee functional recovery (assessed by knee range of motion, quadriceps strength, daily mobilization distance, and time to first straight-leg raising). Tertiary outcomes included the postoperative swelling ratio and complication rates.

RESULTS

Within 24 h of surgery, patients in the magnesium sulfate group had markedly lower VAS pain scores during motion and at rest. After the addition of magnesium sulfate, the analgesic effect was dramatically prolonged, leading to a reduction in morphine dosage within 24 h and the total morphine dosage postoperatively. Postoperative inflammatory biomarker levels were significantly reduced in the magnesium sulfate group compared with the control. There were no considerable differences between the groups in terms of the postoperative length of stay and knee functional recovery. Both groups had similar postoperative swelling ratios and incidences of complications.

CONCLUSIONS

The addition of magnesium sulfate to the analgesic cocktail for PIA can prolong postoperative analgesia, decrease the consumption of opioids, and effectively alleviate early postoperative pain after TKA.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2200056549. Registered on 7 February 2022, https://www.chictr.org.cn/showproj.aspx?proj=151489 .

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.

Addition of infiltration between the popliteal artery and the capsule of the posterior knee (IPACK) to local infiltration analgesia for total knee arthroplasty: a prospective randomized controlled trial

BACKGROUND

Local infiltration analgesia (LIA) is a popular analgesic technique commonly administered during total knee arthroplasty (TKA). Recent studies have demonstrated that the infiltration between the popliteal artery and the capsule of the posterior knee (IPACK) can be complementary to analgesic modalities. However, the combined and relative efficacy of LIA and IPACK is unclear. We aimed to evaluate the analgesic and functional outcomes among LIA, IPACK, and LIA+IPACK.

MATERIALS AND METHODS

A total of 120 patients undergoing primary TKA were randomly allocated to 1 of 3 groups: LIA (50 mL of 0.25% ropivacaine and 2.0 μg/mL epinephrine); IPACK (20 mL of 0.25% ropivacaine and 2.0 μg/mL epinephrine); and LIA+IPACK. The primary outcome was the visual analog scale (VAS) pain score. Secondary outcomes were opioid use, knee range of motion (ROM), quadriceps muscle strength, mobilization distance, timed up and go (TUG) test, and postoperative complications.

RESULTS

The mean VAS pain scores were significantly higher after using IPACK alone than after using LIA+IPACK and LIA within 24 hours (all p＜0.05). LIA+IPACK had lower mean VAS pain scores than LIA when the knees were at rest (within 12 hours, p < 0.05) and flexion (within 8 hours, p＜0.05). Patients receiving LIA+IPACK and LIA had significantly lower morphine equivalents (ME) than those receiving IPACK alone within 24 hours (26.3, 28.9 versus 47.8, both p＜0.05) and during hospitalization (98, 101.6, versus 128.4 both p＜0.05). Both LIA+IPACK and LIA had higher ROM (within two days), higher level of muscle strength (within 12 hours), longer mobilization distances (within one day), and shorter TUG time (till discharge) compared with IPACK alone (all p＜0.05), while LIA+IPACK only had a higher knee ROM than LIA on the first postoperative day (p＜0.05). There was no significant difference in any other outcomes.

CONCLUSIONS

This randomized controlled trial demonstrated that there were significantly lower pain scores, less opioid consumption, and better functional results with LIA+IPACK and LIA when compared with IPACK alone, suggesting that IPACK alone was inferior for pain control.

Motor-Sparing Effect of Adductor Canal Block for Knee Analgesia: An Updated Review and a Subgroup Analysis of Randomized Controlled Trials Based on a Corrected Classification System

OBJECTIVE

Discrepancies in the definition of adductor canal block (ACB) lead to inconsistent results. To investigate the actual analgesic and motor-sparing effects of ACB by anatomically defining femoral triangle block (FTB), proximal ACB (p-ACB), and distal ACB (d-ACB), we re-classified the previously claimed ACB approaches according to the ultrasound findings or descriptions in the corresponding published articles. A meta-analysis with subsequent subgroup analyses based on these corrected results was performed to examine the true impact of ACB on its analgesic effect and motor function (quadriceps muscle strength or mobilization ability). An optimal ACB technique was also suggested based on an updated review of evidence and ultrasound anatomy.

MATERIALS AND METHODS

We systematically searched studies describing the use of ACB for knee surgery. Cochrane Library, PubMed, Web of Science, and Embase were searched with the exclusion of non-English articles from inception to 28 February 2022. The motor-sparing and analgesic aspects in true ACB were evaluated using meta-analyses with subsequent subgroup analyses according to the corrected classification system.

RESULTS

The meta-analysis includes 19 randomized controlled trials. Compared with the femoral nerve block group, the quadriceps muscle strength (standardized mean difference (SMD) = 0.33, 95%-CI [0.01; 0.65]) and mobilization ability (SMD = -22.44, 95%-CI [-35.37; -9.51]) are more preserved in the mixed ACB group at 24 h after knee surgery. Compared with the true ACB group, the FTB group (SMD = 5.59, 95%-CI [3.44; 8.46]) has a significantly decreased mobilization ability at 24 h after knee surgery.

CONCLUSION

By using the corrected classification system, we proved the motor-sparing effect of true ACB compared to FTB. According to the updated ultrasound anatomy, we suggested proximal ACB to be the analgesic technique of choice for knee surgery. Although a single-shot ACB is limited in duration, it remains the candidate of the analgesic standard for knee surgery on postoperative day 1 or 2 because it induces analgesia with less motor involvement in the era of multimodal analgesia. Furthermore, data from the corrected classification system may provide the basis for future research.

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.

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.

IPACK (Interspace between the Popliteal Artery and the Capsule of the Posterior Knee) Block Combined with SACB (Single Adductor Canal Block) Versus SACB for Analgesia after Total Knee Arthroplasty

OBJECTIVES

To evaluate the combination of the infiltration between the popliteal artery and the posterior capsule of the knee (iPACK) block and single adductor canal block (SACB) versus SACB for motor-sparing knee analgesia effects after total knee arthroplasty (TKA).

METHODS

PubMed, Ovid, Cochrane Library, and other databases were searched from the inception to January 2021. Randomized controlled trials (RCTs) comparing patients receiving iPACK plus SACB with patients receiving SACB after TKA were included. The included studies were assessed by two reviewers according to the Cochrane risk of bias criteria. Meta-analysis was performed with STATA 13.0 software, the risk ratios (RR) and mean differences (MD) were used to compare dichotomous and continuous variables. The primary outcome was ambulation pain and secondary outcomes were rest pain, opioid consumption, function ability, clinical outcomes, and complications.

RESULTS

Seven RCTs (304 knees in iPACK + SACB group; 305 knees in SACB group) were included. The follow-up periods ranged from 2 days to 3 months. Pooled data indicated lower pain scores at ambulation (p < 0.0001) for iPACK + SACB. When comparing the pain scores of subgroups analyzed at specific periods, lower scores in subgroups within 12 h (at rest and ambulation) and after 48 h (at ambulation) were observed in the iPACK + SACB group. Analysis demonstrated greater reduction in morphine consumption (p = 0.007) in the iPACK + SACB group. The iPACK + SACB group is also superior to the SACB group regarding function ability, which included range of motion (ROM) (p = 0.001), time up to go (TUG) test (p = 0.030), and ambulation distance (p < 0.0001). No difference was found in clinical outcomes or complications.

CONCLUSIONS

With the iPACK added to SACB, pain scores, morphine consumption, functional ability were improved. Additional high-quality studies are required to further address this topic.

Comparison Between Periarticular Analgesia Versus Intraarticular Injection for Effectiveness and Safety After Total Knee Arthroplasty

PURPOSE

In most studies, local infiltration analgesia (LIA) can provide better analgesic effect in the early postoperative period, but the optimal technique is unknown. Our study was designed to evaluated the early clinical efficacy and safety of periarticular analgesia versus intraarticular injection in Total knee arthroplasty (TKA).

DESIGN

A prospective study was conducted on 100 patients admitted for TKA. Subjects were divided into two groups: 50 in group A, 50 in Group B.

METHODS

Patients in group A received periarticular analgesia with ropivacaine 300 mg and morphine 5 mg (the drugs were diluted with saline to 50 ml) in the periosteal borders, posterior capsule and extensor apparatus and subcutaneous tissues during surgery. After stitching of joint capsule, tranexamic acid (TXA) 2 g (20 ml) was injected into the articular cavity. Group B patients had all of the 70 mL mixture (ropivacaine 300 mg, morphine 5 mg and TXA 2 g) injected intraarticularly after stitching of the joint capsule. We assessed postoperative length of stay (LOS), knee functional outcome, pain, and complications after surgery.

FINDINGS

There was no statistical difference in visual analog scale (VAS) scores for knee pain between the two groups on postoperative day (POD)1, 3, or 30 (P > .05). Mean postoperative LOS was 7.40 ± 1.98 days in Group A, compared to 8.02 ± 2.09 days in Group B (P > .05). No significant differences between groups were seen in the mean swelling ratio (P > .05), and no significant differences were found in the Hospital for Special Surgery (HSS) knee score and range of motion (ROM) at 30 days follow-up (P > .05). There was also no statistical difference in the incidence of complications (such as superficial wound infection, deep vein thrombosis (DVT) and nausea and vomiting) between the Group A and the Group B.

CONCLUSIONS

In conclusion, it seems that intraarticular injection had a similar analgesic effect compared with periarticular injection when adopting a multi-modal analgesia regimen. Our results suggest that there is no obvious advantage with the use of periarticular injections compared to intraarticular injection. The authors believe that intraarticular injection may be a better technique compared with periarticular injections in the absence of a drainage tube because intraarticular injection can reduce the number of surgical steps and have similar postoperative outcomes.

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.

Liposomal Bupivacaine in Adductor Canal Blocks Before Total Knee Arthroplasty Leads to Improved Postoperative Outcomes: A Randomized Controlled Trial

BACKGROUND

This study compares the use of liposomal bupivacaine (Exparel) versus ropivacaine in adductor canal blocks (ACB) before total knee arthroplasties (TKAs).

METHODS

From the months of April 2020 to September 2021, 147 patients undergoing unilateral primary TKA were asked to participate in this prospective, double-blinded randomized controlled trial. Each patient received an iPACK block utilizing ropivacaine and was additionally randomized to receive an ACB with Exparel or Ropivacaine. For each patient, demographic information, inpatient hospital information, postoperative opioid use, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire scores were collected.

RESULTS

Overall, 100 patients were included (50 in each cohort). The Exparel group had a lower hospital length of stay compared to the Control group (36.3 vs 49.7 hours, P < .01). Patients in the Exparel group reported an increased amount of Numerical Rating Scale pain score improvement at all postoperative timepoints. These patients also used a lower amount of inpatient opioids (40.9 vs 47.3 MME/d, P = .04) but a similar amount of outpatient opioids (33.4 vs 32.1 MME/d, P = .351). Finally, the Exparel group had increased improvements in all WOMAC subscores and total scores at most timepoints compared to the Control group (P < .05).

CONCLUSION

Exparel peripheral regional nerve blocks lead to decreases in pain levels, shorter hospital lengths of stay, inpatient opioid usage, and improved WOMAC scores. Exparel can be safely used in ACB blocks before TKA to help in controlling postoperative pain and decrease length of stay.

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 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.

Regional anesthesia for orthopedic procedures: What orthopedic surgeons need to know

Regional anesthesia is an integral component of successful orthopedic surgery. Neuraxial anesthesia is commonly used for surgical anesthesia while peripheral nerve blocks are often used for postoperative analgesia. Patient evaluation for regional anesthesia should include neurological, pulmonary, cardiovascular, and hematological assessments. Neuraxial blocks include spinal, epidural, and combined spinal epidural. Upper extremity peripheral nerve blocks include interscalene, supraclavicular, infraclavicular, and axillary. Lower extremity peripheral nerve blocks include femoral nerve block, saphenous nerve block, sciatic nerve block, iPACK block, ankle block and lumbar plexus block. The choice of regional anesthesia is a unanimous decision made by the surgeon, the anesthesiologist, and the patient based on a risk-benefit assessment. The choice of the regional block depends on patient cooperation, patient positing, operative structures, operative manipulation, tourniquet use and the impact of post-operative motor blockade on initiation of physical therapy. Regional anesthesia is safe but has an inherent risk of failure and a relatively low incidence of complications such as local anesthetic systemic toxicity (LAST), nerve injury, falls, hematoma, infection and allergic reactions. Ultrasound should be used for regional anesthesia procedures to improve the efficacy and minimize complications. LAST treatment guidelines and rescue medications (intralipid) should be readily available during the regional anesthesia administration.

Additional nerve blocks are not superior to multiple-site infiltration analgesia in total knee arthroplasty under adductor canal block

Background

Adductor canal block (ACB) with additional nerve blocks (ANBs) is reported to provide adequate analgesia and enhanced functional rehabilitation in total knee arthroplasty (TKA). The present study aims to evaluate whether ANBs are superior to multiple-site infiltration analgesia (MIA) in patients undergoing TKA under ACB.

Methods

We enrolled 530 patients undergoing primary TKA from 2015 to 2019 at our institution in this retrospective cohort study. Patients were divided into two groups: Group A was treated with ANBs + ACB; Group B was treated with MIA + ACB. Primary outcomes were pain scores and morphine consumption. Functional recovery was the secondary outcome. Other outcomes included satisfaction score, cost-effectiveness, adverse events, and length of hospital stay (LOS).

Results

Pain scores at rest and morphine consumption were slightly lower in the ANBs + ACB group than in the MIA + ACB group. No significant difference was found in functional recovery, post-operative complications or LOS between the groups. Meanwhile, the cost of analgesic intervention in the MIA + ACB group was less than that in the ANBs + ACB group.

Conclusion

The present study suggests that ANBs do not provide superior pain relief compared to MIA for patients undergoing TKA under ACB.

Trial registration

Chinese Clinical Trial Registry, ChiCTR2100043227. Registered 9 February 2021, https://www.chictr.org.cn/showproj.aspx?proj=121745.

Efficacy of Two Unique Combinations of Nerve Blocks on Postoperative Pain and Functional Outcome After Total Knee Arthroplasty: A Prospective, Double-Blind, Randomized Controlled Study

BACKGROUND

This study aimed to explore the efficacy of two unique combinations of nerve blocks on postoperative pain and functional outcome after total knee arthroplasty (TKA).

METHODS

Patients scheduled for TKA were randomized to receive a combination of adductor canal block (ACB) + infiltration between the popliteal artery and capsule of the posterior knee block (IPACK) + sham obturator nerve block (ONB) + sham lateral femoral cutaneous nerve block (LFCNB) (control group), or a combination of ACB + IPACK + ONB + sham LFCNB (triple nerve block group), or a combination of ACB + IPACK + ONB + LFCNB (quadruple nerve block group). All patients received local infiltration analgesia. Primary outcome was postoperative morphine consumption. Secondary outcomes were the time until first rescue analgesia, postoperative pain assessed on the visual analog scale (VAS), QoR-15 score, functional recovery of knee, and postoperative complications.

RESULTS

Compared with the control group, the triple and quadruple nerve block groups showed significantly lower postoperative morphine consumption (17.2 ± 9.7 mg vs. 11.2 ± 7.0 mg vs. 11.4 ± 6.4 mg, P = .001). These two groups also showed significantly longer time until first rescue analgesia (P = .007 and .010, respectively, analyzed with Kaplan-Meier method), significantly lower VAS scores on postoperative day 1 (P < .01), significantly better QoR-15 scores on postoperative days 1 and 2 (P < .001), and significantly better functional recovery of knee including range of motion (P = .002 and .001 on postoperative days 1 and 2), and daily ambulation distance (P < .001 and P = .004 on postoperative days 1 and 2). However, the absolute change in morphine consumption, VAS scores, and QoR-15 scores did not exceed the reported minimal clinically important differences (MCIDs) (morphine consumption: 10 mg; VAS scores: 1.5 at rest and 1.8 during movement; QoR-15 scores: 8.0). The MCIDs of other outcomes have not been reported in literature. The triple and quadruple nerve block groups showed no significant differences in these outcomes between each other. The three groups did not show a significant difference in complication rates.

CONCLUSION

Adding ONB or ONB + LFCNB to ACB + IPACK can statistically reduce morphine consumption, improve early pain relief, and functional recovery. However, the absolute change in morphine consumption, VAS scores, and QoR-15 scores did not exceed the MCIDs. Based on our findings and considering the sample size of this study, there is not enough clinical evidence to support the triple or quadruple nerve block use within a multimodal analgesic pathway after TKA.

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.

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.

Comparison of Intravenous and Topical Dexamethasone for Total Knee Arthroplasty: A Randomized Double-Blinded Controlled Study of Effects on Dexamethasone Administration Route and Enhanced Recovery

BACKGROUND

The optimal route for dexamethasone (DEX) administration regimen for patients undergoing primary TKA has not been investigated. This study aims to determine whether intravenous and topical DEX provide different clinical effects in patients with TKA.

METHODS

In this double-blinded, placebo-controlled trial, 90 patients undergoing primary TKA were randomized to intravenous DEX group (n = 45) or topical DEX group (n = 45, DEX applied in anesthetic cocktail for periarticular injection). The primary outcome was postoperative VAS pain score and morphine consumption. Secondary outcomes were included knee swelling, knee flexion, and extension angle, Knee Society Score (KSS), and postoperative hospital stays. Tertiary outcomes assessed the blood-related metrics, including inflammatory biomarkers and fibrinolysis parameters. Finally, nausea and vomiting and other adverse events were compared.

RESULTS

The topical administration of DEX provide lower pain score at 2h, 8h, 12h at rest (P < .05) and 12h, 24h with activity (P < .05), and less knee swelling in the first postoperative day (P < .05), while intravenous DEX was more effective in decreasing blood inflammatory biomarkers, including C-reactive protein (CRP) at postoperative 24h (P < .05) and interleukin-6 (IL-6) at postoperative 24h, 48h (P < .05), and reducing postoperative nausea (P < .05) for patients receiving TKA. However, there was no significant difference in knee flexion and extension angle, KSS, postoperative hospital stays, and complications occurrence (P > .05) between intravenous and topical DEX after TKA.

CONCLUSION

Topical administration of DEX provided better clinical outcomes on postoperative pain management and knee swelling early after TKA, while intravenous DEX was more effective in decreasing blood inflammatory biomarkers and preventing postoperative nausea.

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.