Adductor Canal Block Combined With iPACK (Interspace Between the Popliteal Artery and the Capsule of the Posterior Knee) Block vs Periarticular Injection for Analgesia After Total Knee Arthroplasty: A Randomized Noninferiority Trial

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.

The Efficacy of Preoperative Video-Based Opioid Counseling on Postoperative Opioid Consumption After Total Knee Arthroplasty: A Prospective Randomized Controlled Trial

BACKGROUND

There are myriad strategies to reduce opioid consumption after total knee arthroplasty (TKA). Recent studies have suggested that preoperative counseling may reduce opioid use after a variety of orthopedic procedures. The purpose of this study was to investigate whether preoperative video-based patient education regarding opioid use and abuse reduces opioid consumption after TKA.

METHODS

In this prospective randomized controlled trial, patients were randomized before TKA to either receive preoperative video-based counseling or not. Counseling involved a pretaped 5-minute video that educated patients on statistics regarding the "opioid epidemic" and discussed safe use and alternatives to opioids after TKA. There were no significant differences in baseline patient demographics between groups. All patients received a similar multimodal perioperative pain management protocol and completed a daily diary for 2 weeks postoperatively. Diary records measured pain levels using a visual analog score, opioid consumption, side effects experienced, and patient opinion and satisfaction regarding their pain control.

RESULTS

Patients in the counseling group consumed significantly less morphine milligram equivalents on postoperative days 0 to 3 (78.8 versus 106.1, P = .020) and in week one postoperatively (129.9 versus 180.7, P = .028), with a trend of less consumption over 2 weeks postoperatively (186.9 versus 239.1, P = .194). There were no significant differences in the number of patients requiring refills, side effects, or daily pain levels between the 2 groups.

CONCLUSIONS

This study found significantly decreased opioid consumption within the first week after TKA in patients who received preoperative video counseling.

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

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

Intraoperative Surgeon-Performed versus Conventional Anesthesiologist-Performed Continuous Adductor Canal Block in Total Knee Arthroplasty: A Randomized Controlled Trial

A continuous adductor canal block (cACB) for pain control in total knee arthroplasty (TKA) is always performed by an anesthesiologist. A surgeon-performed cACB during surgery is somewhat questionable in terms of feasibility, reproducibility, and efficacy. This study was divided into two phases. In Phase 1 study, an experimental dissection of 16 cadaveric knees to expose the saphenous nerve and related muscles around the adductor canal was conducted. The extent of dye after injection via a catheter inserted into the adductor canal at the time of TKA was evaluated. In Phase II, a randomized controlled trial study comparing clinical outcomes between surgeon-performed (Group 1) and anesthesiologist-performed cACB (Group 2) during TKA in 63 patients was evaluated. The visual analogue scale (VAS) at rest and during movement at several time points and functional outcomes during hospitalization were compared. The Phase I study demonstrated surgeon-performed cACB during surgery feasible and reproducible with consistent dye extension into the adductor canal after injection via a catheter. In the Phase II study, 29 patients of Group 1 and 30 patients of Group 2 completed the evaluation with no differences in baseline parameters. The VAS during movement at 24 and 36 hours, quadriceps strength, time up and go test, and knee motion at different time points, and total morphine consumption showed no differences between both groups. There were no procedure-related complications. The surgeon-performed cACB during surgery was feasible and reproducible with similar VAS scores and functional outcomes during hospitalization to anesthesiologist cACB. Level of evidence is Level I, prospective randomized trial.

Combined Single-Shot Infiltration Between the Popliteal Artery and Capsule of the Knee and Adductor Canal Block With Bupivacaine, Dexmedetomidine, and Dexamethasone for Total Knee Arthroplasty: A Propensity-Matched Analysis

Background

To investigate if combined single-shot adductor canal blockade (ACB) and infiltration between the popliteal artery and capsule of the knee (IPACK) provide better postoperative pain management compared to ACB alone for patients undergoing unilateral total knee arthroplasty (TKA).

Methods

This retrospective cohort study included adult patients who underwent primary, unilateral TKA. Patients were separated into 2 cohorts: single-shot ACB alone (performed with bupivacaine 0.25%) and combined single-shot ACB + IPACK (performed with bupivacaine 0.25%, dexmedetomidine 1 mg/kg, and dexamethasone 4 mg). Patients were propensity-matched 1:1. The primary study outcome was total opioid consumption converted to morphine milligram equivalents (MME) per eight-hour interval and postoperative day. Secondary outcomes included pain scores, length of stay, ambulation distance, return to emergency department, hospital readmission, and 30-day adverse events.

Results

One hundred eighty patients were identified, of which propensity matching used 71% to yield 64 patients receiving ACB alone and 64 receiving combined ACB + IPACK. Combined ACB + IPACK had significantly lower total summative MME throughout the entire postoperative stay (P = .002) and cumulatively after the first 24 hours (P < .001). Combined ACB + IPACK also had lower mean pain scores for 0-8 hours (P = .005) and 8-16 hours (P = .009) postoperatively. There were no significant differences in secondary outcomes.

Conclusions

Combined single-shot ACB + IPACK block was associated with lower total narcotic intake and mean pain scores during most of the immediate postoperative period following primary, unilateral TKA compared to ACB alone. Implementing longer-acting, single-shot ACB + IPACK for TKA can balance effective and more selective pain management with early rehabilitation.

Posteromedial Periarticular Injection in Total Knee Arthroplasty: A Cadaveric Study

Achieving optimal pain control in total knee arthroplasty has improved with the use of regional anesthesia and periarticular injections (PAIs). When performing a PAI, the relative location of the anesthetic spread is not well defined in comparison with an adductor canal block (ACB). In this study, our aim was to evaluate the location of posteromedial PAI spread compared with a surgeon administered ACB. One PAI and one surgeon-administered ACB were performed in the contralateral limbs of four human cadavers. The injectate was composed of methylene blue dye to visually inspect the dye spread from the tip of the needle. Dissections were performed on each cadaver to quantify the dye spread from the tip of the needle and compare the location of the dye spread. Dye spread location was characterized as either entering the adductor canal or including the posterior capsule. The mean distance of dye spread from the needle tip to the proximal most aspect of the dyed tissue was 10.125 cm in the ACB group compared with 6.5 cm in the posteromedial PAI group. In the ACB group, 4 of 4 injections were present in the adductor canal block group compared with 3 of 4 in the posteromedial PAI group. The posteromedial PAI group also had 3 of 4 injections involve the area around the posterior capsule compared with 0 of 4 in the ACB group. Posteromedial PAI appears to provide local delivery to both the adductor canal and the posterior capsule. Intraoperative, surgeon-administered ACB reliably delivers injectate to the adductor canal only but may allow for more proximal dye spread. Posteromedial PAI may provide a benefit in delivering injectate to the posterior capsule in addition to the ACB. Additional clinical studies are necessary to determine the clinical effects of this finding.

Ultrasound-guided dexmedetomidine combination with modified high fascia iliaca compartment block for arthroscopic knee surgery: what is the optimal dose of dexmedetomidine?

BACKGROUND

Total knee arthroplasty (TKA) is a common orthopedic procedure for end-stage knee osteoarthritis. Although effective in relieving pain and improving function, postoperative pain is still a common and distressing problem for many patients. This study aims to investigate efficacy of combined administration of dexmedetomidine and modified high fascia iliaca compartment block (H-FICB) in managing acute and chronic pain after TKA, as well as to identify the optimal dosage of dexmedetomidine.

METHODS

A double-blind, randomized controlled trial was conducted to evaluate the effects of dexmedetomidine in patients undergoing TKA. A total of 96 patients undergoing TKA were randomly assigned to one of three groups, were treated with different doses of dexmedetomidine All groups received H-FIB. Pain scores, opioid consumption, side effects, and quality of life were recorded 48 h postoperatively.

RESULTS

The intraoperative consumption of remifentanil and propofol in Group Db was significantly reduced compared with that in Group D0 and Da (P < 0.05). Compared with D0 and Da group, Db group had the lowest number of rescue analgesia, analgesia time and morphine accumulative dosage 48 h after operation (P < 0.05). The Db group had the lowest scores on the numerical rating scale at rest (P < 0.05) and during movement (P < 0.01), followed by the Da group and then the D0 group. Additionally, the incidence of nausea and vomiting was significantly reduced in the Db group (P < 0.05). Furthermore, the Db group had the lowest incidence of chronic pain (P < 0.05).

DISCUSSION

In comparison to the other two groups, the administration of combined dexmedetomidine and H-FIB resulted in a significant reduction in pain scores, opioid consumption, and side effects. The optimal dosage of dexmedetomidine was determined to be 1 μg/kg, which provided the most favorable pain relief with minimal adverse effects.

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.

Intraoperative landmark-based genicular nerve block versus periarticular infiltration for postoperative analgesia in total knee arthroplasty: a randomized non-inferiority trial

INTRODUCTION

Genicular nerve blocks (GNBs) are an emerging technique that have been used as a part of multimodal analgesia for total knee arthroplasty. The efficacy of intraoperative landmark-based GNBs, a recently introduced technique, has been established. We hypothesized that it would provide non-inferior postoperative analgesia compared with periarticular infiltration (PAI) when combined with continuous adductor canal block.

METHODS

This study randomized 140 patients undergoing total knee arthroplasty to receive either intraoperative landmark-based GNB (GNB group) or PAI (PAI group), with 139 completing the study. The primary outcomes were the pain scores at rest and during movement at 12 hours postoperatively on an 11-point Numerical Rating Scale; the non-inferiority margin was 1. Pain scores at additional time points, intravenous morphine consumption, time to first rescue analgesia, functional performance and muscle strength tests, and sleep disturbance were also assessed.

RESULTS

At 12 hours postoperatively, the PAI and GNB groups had median resting pain scores of 0 (0-2) and 0 (0-2), respectively. The median difference was 0 (95% CI -0.4 to 0.4, p=1), with the 95% CI upper limit below the prespecified non-inferiority margin. The median pain score during movement was 1.5 (0-2.3) and 2 (1-3.1) in the PAI and GNB groups, respectively. The median difference was 0.9 (95% CI 0.3 to 1.6, p=0.004), failing to demonstrate non-inferiority. The GNB group had higher intravenous morphine consumption at 12 hours postoperatively and a shorter time to first rescue analgesia.

CONCLUSIONS

GNB compared with PAI provides non-inferior resting pain relief. Non-inferiority was not established for pain during movement.

TRIAL REGISTRATION NUMBER

TCTR20220406001 (www.thaiclinicaltrials.org).

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.

Retrospective Analysis of Surgeon-Placed Nerve Block and Indwelling Catheter in the Adductor Canal in Total Knee Arthroplasty

INTRODUCTION

 Total knee arthroplasty (TKA) is now being performed in the outpatient setting, and often the postoperative pain is managed with opioid analgesics. Non-opioid pain management modalities are in crucial demand, and we propose a surgical technique that can potentially result in less pain and the decrease in the use of opioid analgesia following TKA. The purpose of this study was to investigate the safety and efficacy of a novel peripheral nerve block (PNB) that includes a single injection and catheter placement for a continuous regional nerve block in total knee arthroplasty.

METHODS

 Fifty-six patients underwent TKA by a single surgeon utilizing the novel method. Patient-reported outcomes were entered into an outcomes database and compared to an aggregate of over 3,500 comparative TKA patients. A visual analog scale (VAS) evaluated perioperative pain. Patient perioperative opioid usage, expectations of pain control, the incidence of common side effects, and the average hospital length of stay (LOS) were collected.

RESULTS

 Compared to the aggregate of patients in the database, the patients who received the novel surgeon-placed adductor canal block (ACB) and catheter placement reported findings that suggest this technique can possibly lead to a decrease in the severity of pain in addition to a reduction in side effects and the need for opioid analgesia. LOS for these patients was short, and patient satisfaction scores were excellent for the surgeon performing this technique.

CONCLUSIONS

Using the placement technique described, surgeons can reproducibly perform a single injection of PNB and place an indwelling catheter in the adductor canal through direct visualization of the muscles that make up the borders of the adductor canal. This technique offers potential advantages over pain management modalities that can be elucidated in further studies. The power of this study is limited due to these findings having not been analyzed for statistical significance.

Effect of Adding Perineural Methylprednisolone to Peripheral Nerve Blocks Combined With Intravenous Dexamethasone for Prolonged Postdischarge Analgesia After Fast-track Total Knee Arthroplasty: A Randomized Controlled Trial

OBJECTIVES

Patients undergoing total knee arthroplasty (TKA) may experience moderate-to-severe subacute pain after hospital discharge that may be undermanaged. We aimed to evaluate the effect of methylprednisolone added to ultrasound-guided peripheral nerve blocks (PNBs) combined with multimodal analgesia including intravenous dexamethasone for prolonged analgesia after early discharge.

MATERIALS AND METHODS

We randomized 80 patients who underwent fast-track TKA into 2 groups. All patients received a periarticular injection, PNBs, and multiple doses of intravenous dexamethasone. The methylprednisolone group received 140 mg methylprednisolone in PNBs, while the nonmethylprednisolone group did not. The primary outcome was the incidence of moderate-to-severe pain (Numerical Rating Scale ≥4) during the first 12 postdischarge days. The secondary outcomes included pain scores until 3 postoperative months, incidence of rebound pain, functional performances, patient satisfaction, and adverse events.

RESULTS

No significant between-group differences were noted in the incidence of moderate-to-severe pain during the first 12 postdischarge days (nonmethylprednisolone vs. methylprednisolone groups: 70% vs. 69.2%, P=0.941). However, this incidence was significantly higher in the methylprednisolone group between 2 weeks and 1 month (P=0.015) and between 1 and 3 months (P=0.004) postoperatively. No between-group differences in the Numerical Rating Scale scores at the postdischarge time points, incidence of rebound pain, and functional performance results were noted.

DISCUSSION

Adding perineural methylprednisolone to ultrasound-guided PNBs for multimodal analgesia with intravenous dexamethasone did not prolong analgesia and improved the functional ability after fast-track TKA within 12 postdischarge days. However, the incidence moderate-to-severe pain may increase between the 2-week and 3-month follow-up.

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.

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.

Surgeon-Performed Intraoperative Peripheral Nerve Blocks and Periarticular Infiltration During Total Hip and Knee Arthroplasty: A Critical Analysis Review

➢

Surgeon-performed intraoperative peripheral nerve blocks may improve operating room efficiency and reduce hospital resource utilization and, ultimately, costs. Additionally, these blocks can be safely performed intraoperatively by most orthopaedic surgeons, while only specifically trained physicians are able to perform ultrasound-guided peripheral nerve blocks.

➢

IPACK (infiltration between the popliteal artery and capsule of the knee) blocks are at least noninferior to periarticular infiltration when combined with an adductor canal block for analgesia following total knee arthroplasty.

➢

Surgeon-performed intraoperative adductor canal blocks are technically feasible and offer reliable anesthesia comparable with ultrasound-guided blocks performed by anesthesiologists. While clinical studies have shown promising results, additional Level-I studies are required.

➢

A surgeon-performed intraoperative psoas compartment block has been described as a readily available and safe technique, although there is some concern for femoral nerve analgesia, and temporary sensory changes have been reported.

Synergistic effects of robotic surgery and IPACK nerve block on reduction of opioid consumption in total knee arthroplasty

Background

There are numerous strategies to combat postoperative analgesia and expedite recovery after total knee arthroplasty (TKA). The purpose of this study was to determine opioid consumption, length of stay, and functional outcomes after robotic versus standard TKA in the setting of various regional pain modalities.

Methods

A consecutive series of patients treated with unilateral primary robotic or standard TKA from January 2018-February 2021 were retrospectively identified. Regional pain modalities included peri-articular injection (PAI), adductor canal block (ACB), and infiltration between popliteal artery and capsule of knee (IPACK). Patient demographics, operative/perioperative variables, and postoperative function were recorded. Daily opiate consumption was calculated as morphine milligram equivalents (MME). Multivariate regression was performed to control for age, sex, and race.

Results

After review, 283 patients (177 Females; 106 Males) were included. Robotic TKA patients received IPACK + ACB (36), while standard TKA patients received either ACB (45), IPACK + ACB (167), or PAI (35). Daily inpatient opioid consumption in the standard IPACK + ACB (p = 0.02) and robotic IPACK + ACB groups (p = 0.0001) was significantly lower compared to standard ACB. When combined with IPACK block, robotic procedures synergistically lowered opiate consumption (p = 0.004) compared to standard procedures and led to earlier discharge (p = 0.003). The robotic IPACK + ACB cohort also demonstrated improved early ambulation compared to standard ACB, (p = 0.05), whereas the same benefit was not seen for patients who received IPACK during standard TKA.

Conclusions

The utilization of IPACK block decreases inpatient postoperative opioid requirements following TKA. Robotic TKA and IPACK block appeared to have a synergistic effect on opioid consumption and postoperative recovery.

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.

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.

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.

Comparison of iPACK and periarticular block with adductor block alone after total knee arthroplasty: a randomized clinical trial

PURPOSE

The infiltration between the popliteal artery and the capsule of the posterior knee (iPACK) has been described to provide analgesia without loss of muscle strength and is effective in functional recovery. This study compared iPACK + ACB (adductor canal block) with PAI (periarticular infiltration) + ACB and ACB alone in terms of postoperative analgesia and functional improvement.

METHODS

This double-blinded randomized controlled trial included 105 patients undergoing unilateral total knee arthroplasty. Patients received ACB, iPACK + ACB, and PAI + ACB along with spinal anesthesia. The primary outcome was the area under the curve (AUC) numeric rating scale (NRS) at 48 h. Secondary outcomes were cumulative postoperative analgesic consumption within 48 h, timed up-and-go test, range of motion, length of hospital stay, patient satisfaction, and adverse events.

RESULTS

The 48-h AUC movement NRS score in the iPACK + ACB group was significantly lower than in the PAI + ACB and ACB groups (p < 0.05). At the postoperative 48th h, the opioid consumption of the iPACK + ACB group was lower than those of the ACB and PAI + ACB groups (p < 0.001). The patients in the iPACK + ACB group had significantly shorter discharge and mobilization days than the ACB and PAI + ACB groups (p < 0.001).

CONCLUSIONS

The adding of an iPACK block to the ACB improves postoperative analgesia and reduces opioid consumption. In addition, this approach improves functional performance and reduces hospital stay.

Additional Peripheral Nerve Block to Periarticular Injection Has No Benefit for Patients Undergoing TKA: A Factorial Propensity Score-Matched Analysis Comparing Four Multimodal Analgesic Techniques

BACKGROUND

Controversy remains over what and how many analgesic techniques are required as the most effective multimodal pain regimen in total knee arthroplasty (TKA). This study aimed to evaluate the effect of additional analgesic methods combined with periarticular injection (PAI) analgesia for TKA.

METHODS

Using retrospective cohort data, patients undergoing TKA with spinal anesthesia and PAI were divided into 4 groups. Group A (control) comprised 66 patients; group B (73 patients) had additional adductor canal block; group C (70 patients) obtained additional femoral nerve block, and group D (73 patients) received additional adductor canal block and intrathecal morphine. Propensity score matching was applied to compare visual analog scale (VAS) for pain intensity, cumulative morphine use (CMU), knee flexion angle, straight leg raise, length of hospital stay, and postoperative nausea and vomiting.

RESULTS

There was no significant difference regarding VAS and morphine use, when either group B or C was compared with group A. Group D had significantly lower VAS than groups A, B, and C during the first 24 hours after surgery and required significantly less CMU than groups A and B. However, the pain score of group D increased afterward, with significantly longer length of hospital stay than groups A and B. There was no difference in straight leg raise among the groups.

CONCLUSION

Additional peripheral nerve block to PAI provides no benefit for patients undergoing TKA. Adjuvant intrathecal morphine could significantly reduce the VAS and CMU in the acute postoperative period; however, rebound pain with prolonged hospital stays was observed.

Effect of ultrasound-guided selective sensory nerve blockade of the knee on pain management compared with periarticular injection for patients undergoing total knee arthroplasty: A prospective randomized controlled trial

BACKGROUND

Ultrasound-guided selective sensory nerve blockade (SSNB) of the knee, including an adductor canal block (ACB), anterior femoral cutaneous nerve block, and infiltration between the popliteal artery and posterior capsule of the knee may provide effective motor-sparing knee analgesia for total knee arthroplasty (TKA). We hypothesized that the SSNB would manage pain better on ambulation 24 hours postoperatively compared to periarticular infiltration (PAI), when combined with postoperative continuous ACB.

METHODS

Seventy-two patients undergoing elective TKA under spinal anesthesia were randomly assigned to either SSNB (SSNB group) or intraoperative PAI (PAI group). All patients received postoperative multimodal analgesia, including continuous ACB. The primary outcome was pain on ambulation 24 hours postoperatively. Secondary outcomes included rest and dynamic numerical rating scale pain score, intravenous morphine requirement, functional performance measures, adverse events, satisfaction, and length of stay.

RESULTS

There was no difference in pain score during movement between the groups (mean difference -0.48 [-1.38 to 0.42], p = 0.3) and other immediate overall pain scores 24 hours postoperatively. Patients in the SSNB group had significantly lower intravenous morphine requirement than the PAI group for 48 hours postoperatively (0 [0, 0] vs. 0 [0, 2]; p = 0.008). There was no intergroup difference in the performance-based measures, satisfaction, and length of stay.

CONCLUSIONS

The SSNB did not provide superior postoperative analgesia, or improvement in immediate functional performance. However, it may result in lower opioid consumption postoperatively when compared with the intraoperative PAI.

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.

Anesthesia for knee arthroscopy: which nerves should be blocked?

Nowadays knee arthroscopy is the most common orthopedic procedure. It is used to diagnose and treat various pathological conditions. Usually knee arthroscopy can be performed using spinal anesthesia. The article presents a successful experience of using a combined technique, which consist in a unilateral subarachnoid anesthesia with additional adductor canal block and blocks of the articular branches of the sciatic and obturator nerves.

The analgesic efficacy of anterior femoral cutaneous nerve block in combination with femoral triangle block in total knee arthroplasty: a randomized control trial

Background

Ultrasound-guided femoral triangle block (FTB) can provide motor-sparing anterior knee analgesia. However, it may not completely anesthetize the anterior femoral cutaneous nerve (AFCN). We hypothesized that an AFCN block (AFCNB) in combination with a FTB would decrease pain during movement in the immediate 12-hour postoperative compared with a FTB alone.

Methods

Eighty patients scheduled to undergo total knee arthroplasty (TKA) were randomized to receive either FTB alone (FTB group) or AFCNB with FTB (AFCNB + FTB group) as a part of the multimodal analgesic regimen. The primary outcome was pain during movement 12 hours postoperatively. Secondary outcomes included numeric rating scale (NRS) pain scores, incidence of surgical incision site pain, intravenous morphine consumption, immediate functional performance, patient satisfaction, and length of hospital stay.

Results

The NRS pain scores on movement 12 hours postoperatively were significantly lower in patients of AFCNB + FTB group compared to those in patients of FTB group (mean difference, -2.02 [95% confidence interval: -3.14, -0.89], P < 0.001). Incidence of pain at the site of surgical incision in 24 hours postoperatively and morphine consumption in 48 hours postoperatively were significantly lower (P < 0.001) and quadriceps muscle strength at 0 degree immediately after the surgery was significantly greater in patients of AFCNB + FTB group (P = 0.04).

Conclusions

The addition of ultrasound-guided AFCNB to FTB provided more effective analgesia and decreased opioid requirement compared to FTB alone after TKA and may enhance immediate functional performance on the day of surgery.

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.