A randomized comparison of proximal and distal ultrasound-guided adductor canal catheter insertion sites for knee arthroplasty

Does Proximal Adductor Canal Block Provide Better Analgesic Efficacy than Distal Adductor Canal Block in Patients Undergoing Knee Arthroplasty: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

To compare the analgesic efficacy and adverse events of proximal versus distal ACB for adults undergoing knee arthroplasty, we searched PubMed, Cochrane, Web of Science, and Embase to identify all eligible randomized controlled trials (RCTs). The study quality of the RCTs was evaluated using the Cochrane risk of bias assessment tool. Heterogeneity among studies was examined by Cochrane Q test. Our primary outcomes were pain intensity at rest/during movement and morphine consumption. Statistical analyses were conducted by RevMan Software. Seven eligible studies involving 400 subjects were included in this meta-analysis with 202 participants in the proximal ACB group and 198 participants in the distal ACB group. The results demonstrated that proximal ACB provided significantly better pain relief at rest at 2 h (SMD -0.27, 95% CI -0.54 to -0.01, four trials, 222 participants, I2 = 0, p = 0.04) and 24 h (SMD -0.28, 95% CI -0.48 to -0.08, seven trials, 400 participants, I2 = 0, p = 0.006) following the surgery. We found no evidence of a difference in postoperative pain intensity at other timepoints. Furthermore, we noted no evidence of a difference in cumulative morphine consumption and occurrence of adverse events. Proximal ACB provides better pain relief and comparable adverse effects profile compared with distal ACB. The analgesic benefit offered by proximal ACB, however, did not appear to extend beyond the first 24 h. The overall evidence level was mostly low or very low, which requires more well-organized multicenter randomized trials in the future.

Proximal versus distal adductor canal catheters for total knee arthroplasty: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Total knee arthroplasty (TKA) is associated with severe postoperative pain. Continuous adductor canal blockade provides analgesia while preserving quadriceps muscle strength. Nevertheless, uncertainty still exists as to the optimal adductor canal catheter placement approach. We sought to conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing the analgesic effects of proximal vs distal adductor canal catheters in patients undergoing TKA.

SOURCE

We systematically searched PubMed, EMBASE, and Cochrane for RCTs comparing distal and proximal adductor canal catheters for TKA regarding critical clinical outcomes in adult patients. Statistical analysis was performed using R version 4.1.2 (R Foundation for Statistical Computing, Vienna, Austria). Heterogeneity was assessed using the Cochran Q test and I2 statistics. Trial sequential analysis (TSA) was performed to evaluate the risk of random errors and the uncertainty of our results. The risk of bias was appraised according to the RoB-2 tool.

PRINCIPAL FINDINGS

Six RCTs and 352 patients were included, of whom 151 (42.9%) were male, and 175 (49.7%) were randomized to undergo proximal adductor canal catheter placement. Due to the randomized nature of the studies, baseline characteristics were similar between groups. There were no statistical differences between proximal and distal adductor canal catheters regarding cumulative opioid consumption in the first 24 hr (mean difference [MD], -4.86; 95% confidence interval [CI], -15.19 to 5.47; P = 0.36; four RCTs; 240 patients); pain scores at rest (MD, 0.41; 95% CI, -1.23 to 0.40; P = 0.32; six RCTs; 350 patients); and pain scores with movement for the first 24 hr (MD, -0.25; 95% CI, -0.85 to 0.35; P = 0.42; four RCTs; 246 patients). In the TSA, the required information size was not reached, and the Z-curve did not cross the monitoring boundaries in any of the endpoints.

CONCLUSION

These findings suggest that proximal vs distal adductor canal catheter placement in patients undergoing TKA may be equally effective for the outcomes of opioid consumption in the first 24 hr, pain scores at rest, and pain scores with movement in the first 24 hr. Nevertheless, TSA findings suggest insufficient power to definitively conclude no differences between the two techniques.

STUDY REGISTRATION

PROSPERO (CRD42022353576); registered 25 August 2022.

Pro and Con: How Important Is the Exact Location of Adductor Canal and Femoral Triangle Blocks?

In this Pro-Con commentary article, we debate the importance of anterior thigh block locations for analgesia following total knee arthroplasty. The debate is based on the current literature, our understanding of the relevant anatomy, and a clinical perspective. We review the anatomy of the different fascial compartments, the course of different nerves with respect to the fascia, and the anatomy of the nerve supply to the knee joint. The Pro side of the debate supports the view that more distal block locations in the anterior thigh increase the risk of excluding the medial and intermediate cutaneous nerves of the thigh and the nerve to the vastus medialis, while increasing the risk of spread to the popliteal fossa, making distal femoral triangle block the preferred location. The Con side of the debate adopts the view that while the exact location of local anesthetic injection appears anatomically important, it has not been proven to be clinically relevant.

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.

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

Background

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

Methods

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

Results

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

Conclusions

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

Trial registration number

NCT04206150.

Fascial plane blocks: a narrative review of the literature

Fascial plane blocks (FPBs) are increasingly numerous and are often touted as effective solutions to many perioperative challenges facing anesthesiologists. As 'new' FPBs are being described, questions regarding their effectiveness remain unanswered as appropriate studies are lacking and publications are often limited to case discussions or technical reports. It is often unclear if newly named FPBs truly represent a novel intervention with new indications, or if these new publications describe mere ultrasound facilitated modifications of existing techniques. Here, we present broad concepts and potential mechanisms of FPB. In addition, we discuss major FPBs of (1) the extremities (2) the posterior torso and (3) the anterior torso. The characteristics, indications and a brief summary of the literature on these blocks is included. Finally, we provide an estimate of the overall level of evidence currently supporting individual approaches as FPBs continue to rapidly evolve.

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.

Is the proximal adductor canal block a better choice than the distal adductor canal block for primary total knee arthroplasty?: A meta-analysis of randomized controlled trials

BACKGROUND

Total knee arthroplasty is accompanied by moderate to severe postoperative pain. Postoperative pain hampers the functional recovery and lowers patient satisfaction with the surgery. Recently, the adductor canal block (ACB) has been widely used in total knee arthroplasty. However, there is no definite answer as to the location of a continuous block within the ACBs.

METHOD

Randomized controlled trials about relevant studies were searched in PubMed (1996 to Oct 2019), Embase (1996 to Oct 2019), and Cochrane Library (CENTRAL, Oct 2019).

RESULTS

Five studies involving 348 patients met the inclusion criteria. Pooled data indicated that the proximal ACB was as effective as the distal ACB in terms of total opioid consumption (P = .54), average visual analog scale (VAS) score (P = .35), worst VAS score (P = .19), block success rate (P = .86), and time of catheter insertion (P = .54).

CONCLUSIONS

Compared with the distal ACB, the proximal ACB showed similar analgesic efficacy for total opioid consumption, average VAS score, worst VAS score, block success rate, and time of catheter insertion. However, because of the limited number of involved studies, more high-quality studies are needed to further identify the optimal location of the ACB.

Continuous block at the proximal end of the adductor canal provides better analgesia compared to that at the middle of the canal after total knee arthroplasty: a randomized, double-blind, controlled trial

Background

The optimal position for continuous adductor canal block (ACB) for analgesia after total knee anthroplasty (TKA) remians controversial, mainly due to high variability in the localization of the the adductor canal (AC). Latest neuroanatomy studies show that the nerve to vastus medialis plays an important role in innervating the anteromedial aspect of the knee and dives outside of the exact AC at the proximal end of the AC. Therefore, we hypothesized that continuous ACB at the proximal end of the exact AC could provide a better analgesic effect after TKA compared with that at the middle of the AC (which appeared to only block the saphenous nerve).

Methods

Sixty-two adult patients who were scheduled for a unilateral TKA were randomized to receive continuous ACB at the proximal end or middle of the AC. All patients received patient-controlled intravenous analgesia with sufentanil postoperatively. The primary outcome measure was cumulative sufentanil consumption within 24 h after the surgery, which was analyzed using Mann-Whitney U tests. P-values < 0.05 (two-sided) were considered statistically significant. The secondary outcomes included postoperative sufentanil consumption at other time points, pain at rest and during passive knee flexion, quadriceps motor strength, and other recovery related paramaters.

Results

Sixty patients eventually completed the study (30/group). The 24-h sufentanil consumption was 0.22 μg/kg (interquartile range [IQR]: 0.15–0.40 μg/kg) and 0.39 μg/kg (IQR: 0.23–0.52 μg/kg) in the proximal end and middle groups (P = 0.026), respectively. There were no significant inter-group differences in sufentanil consumption at other time points, pain at rest and during passive knee flexion, quadriceps motor strength, and other recovery related paramaters.

Conclusions

Continuous ACB at the proximal end of the AC has a better opioid-sparing effect without a significant influence on quadriceps motor strength compared to that at the middle of the AC after TKA. These findings indicates that a true ACB may not produce the effective analgesia, instead, the proximal end AC might be a more suitable block to alleviate pain after TKA.

Trial registration

This study was registered at ClinicalTrials.gov (NCT03942133; registration date: May 06, 2019; enrollment date: May 11, 2019).

The feasibility of direct adductor canal block (DACB) as a part of periarticular injection in total knee arthroplasty

BACKGROUND

Adductor canal block (ACB) is one of the preferred methods of analgesia in total knee arthroplasty (TKA). However, conventionally its use is time-consuming, requires ultrasound guidance, a trained anaesthesia team and adherence to strict asepsis by members of the allied teams. This study was done to assess the feasibility and safety of direct adductor canal block (DACB) as a part of surgeon-administered periarticular infiltration.

MATERIALS AND METHODS

Thirty computed tomography (CT) angiography films of the patients were retrospectively reviewed. The trajectory of the needle placement for a DACB in relation to the target region of the adductor block was determined. Fourteen knees in seven cadavers, were dissected through a medial parapatellar approach to perform TKA. After administering the DACB using the technique based on CT data, dissection was carried out to ascertain the correct placement of the dye by visualising the stained areas.

RESULTS

The angle of approach in the coronal plane from the entry point to the medial high point and to the adductor hiatus was 10.2° (8-14°) and 6° (3.8-11°), respectively. The angle of approach in the sagittal plane from the entry point to the medial high point and to the adductor hiatus was 7° (5-10.5°) and 29° (19-43°), respectively. In all the 14 cadaveric knees, we confirmed the correct placement of the methylene blue dye as demonstrated by the staining of the adductor canal.

CONCLUSION

The study demonstrates the feasibility of the DACB. This surgeon-driven technique is likely to reduce the cost of the procedure, reduce operating room time and also eliminate the risks of surgical-site contamination.

Proximal versus distal adductor canal blocks for total knee arthroplasty: A protocol for randomized controlled trial

BACKGROUND

Currently, there remains a paucity of literature about the efficiency of proximal adductor canal block (PACB) versus distal adductor canal block (DACB) for pain management after total knee arthroplasty (TKA). The purpose of this study is to perform a randomized controlled trial to compare the efficiency of PACB versus DACB for early postoperative pain treatment after TKA.

METHODS

This study is a 2-arm, parallel-group, randomized controlled trial that is conducted at a single university hospital in China. Subjects presenting for unilateral TKA are randomized in a 1:1 ratio to either a PACB or DACB group. The primary outcome of this noninferiority study is opioid consumption within the first 24 hours following surgery. Secondary outcomes include quadriceps strength, pain scores, distance ambulated, and patient satisfaction. Continuous variables are compared using Student t test.

RESULTS

This clinical trial is expected to provide evidence of whether the PACB and DACB provide similar analgesia after TKA.

TRIAL REGISTRATION

This study protocol was registered in Research Registry (researchregistry5440).

Five-year follow-up to assess long-term sustainability of changing clinical practice regarding anesthesia and regional analgesia for lower extremity arthroplasty

Background

Long-term and sustainable clinical practice changes in anesthesia procedures have not previously been reported. Therefore, we performed a 5-year audit following implementation of a clinical pathway change favoring spinal anesthesia for total knee arthroplasty (TKA). We similarly evaluated a parallel cohort of patients undergoing total hip arthroplasty (THA), who did not undergo a clinical pathway change, and studied utilization rates of continuous peripheral nerve block (CPNB).

Methods

We identified all primary unilateral TKA and THA cases completed from January 2013 through December 2018, thereby including clinical pathway change data from one-year pre-implementation to 5-years post-implementation. Our primary outcome was the overall application rate of spinal anesthesia. Secondary outcomes included CPNB utilization rate, 30-day postoperative complications, and resource utilization variables such as hospital readmission, emergency department visits, and blood transfusions.

Results

The sample included 1,859 cases, consisting of 1,250 TKAs and 609 THAs. During the initial year post-implementation, 174/221 (78.7%) TKAs received spinal anesthesia compared to 23/186 (12.4%) cases the year before implementation (P < 0.001). During the following 4-year period, 647/843 (77.2%) TKAs received spinal anesthesia (P = 0.532 vs. year 1). The number of THA cases receiving spinal anesthesia the year after implementation was 78/124 (62.9%), compared to 48/116 (41.4%) pre-implementation (P = 0.001); however, the rate decreased over the following 4-year period to 193/369 (52.3%) (P = 0.040 vs. year 1). CPNB use was high in both TKA and THA patient groups, and there were no differences in 30-day postoperative complications, hospital readmission, emergency department visits, or blood transfusions between patients who underwent spinal and general anesthesia in both TKA and THA groups.

Conclusions

A clinical pathway change promoting spinal anesthesia for TKA can be effectively implemented and sustained over a 5-year period.

Anesthesia of the anterior femoral cutaneous nerves for total knee arthroplasty incision: randomized volunteer trial

BACKGROUND AND OBJECTIVES

For pain relief after total knee arthroplasty (TKA), an injection at the midthigh level may produce analgesia inferior to that of a femoral nerve block as the anterior femoral cutaneous nerves (intermediate femoral cutaneous nerve (IFCN) and medial femoral cutaneous nerve (MFCN)) are not anesthetized. The IFCN can be selectively anesthetized in the subcutaneous tissue above the sartorius muscle and the MFCN by an injection in the proximal part of the femoral triangle (FT). The primary aim was to investigate the area of cutaneous anesthesia in relation to the surgical incision for TKA and anteromedial knee area after intermediate femoral cutaneous nerve blockade (IFCNB) in combination with an injection in the proximal or distal part of the FT (proximal vs distal femoral triangle block (FTB)).

METHODS

The study was carried out as two separate investigations: first, dissection of nine cadaver sides to verify a technique for IFCNB; second, a volunteer study with 40 healthy volunteers. The surgical midline incision for TKA was drawn bilaterally. All volunteers received an active distal FTB combined with a placebo proximal FTB on one side and vice versa on the other side. All volunteers were randomized to an active IFCNB on one side and placebo IFCNB on the contralateral side.

RESULTS

Identification of IFCN was successful in all cadaver sides. Fifteen out of 20 volunteers had complete anesthesia of the incision line after IFCNB combined with proximal FTB, which was significantly higher compared with proximal FTB alone and with distal FTB+IFCNB. A gap at the anteromedial knee area was present in 2/20 volunteers with proximal FTB compared with 17/20 with distal FTB when all volunteers had active IFCNB.

CONCLUSION

Ultrasound-guided blockade of the IFCN and MFCN anesthetize the surgical midline incision and the anteromedial area of the knee relevant for TKA. In contrast, an injection at the midthigh level produces insufficient cutaneous anesthesia not covering the areas of interest.

TRIAL REGISTRATION NUMBER

EudraCT: 2018-004986-15.

Opioid- and Motor-sparing with Proximal, Mid-, and Distal Locations for Adductor Canal Block in Anterior Cruciate Ligament Reconstruction

Editor’s Perspective

What We Already Know about This Topic

What This Article Tells Us That Is New

Background

The ideal location for single-injection adductor canal block that maximizes analgesia while minimizing quadriceps weakness after painful knee surgery is unclear. This triple-blind trial compares ultrasound-guided adductor canal block injection locations with the femoral artery positioned medial (proximal adductor canal), inferior (mid-adductor canal), and lateral (distal adductor canal) to the sartorius muscle to determine the location that optimizes postoperative analgesia and motor function. The hypothesis was that distal adductor block has (1) a superior opioid-sparing effect and (2) preserved quadriceps strength, compared with proximal and mid-locations for anterior cruciate ligament reconstruction.

Methods

For the study, 108 patients were randomized to proximal, mid-, or distal adductor canal injection locations for adductor canal block. Cumulative 24-h oral morphine equivalent consumption and percentage quadriceps strength decrease (maximum voluntary isometric contraction) at 30 min postinjection were coprimary outcomes. The time to first analgesic request, pain scores, postoperative nausea/vomiting at least once within the first 24 h, and block-related complications at 2 weeks were also evaluated.

Results

All patients completed the study. Contrary to the hypothesis, proximal adductor canal block decreased 24-h morphine consumption to a mean ± SD of 34.3 ± 19.1 mg, (P &lt; 0.0001) compared to 64.0 ± 33.6 and 65.7 ± 22.9 mg for the mid- and distal locations, respectively, with differences [95% CI] of 29.7 mg [17.2, 42.2] and 31.4 mg [21.5, 41.3], respectively, mostly in the postanesthesia care unit. Quadriceps strength was similar, with 16.7%:13.4%:15.3% decreases for proximal:mid:distal adductor canal blocks. The nausea/vomiting risk was also lower with proximal adductor canal block (10 of 34, 29.4%) compared to distal location (23 of 36, 63.9%; P = 0.005). The time to first analgesic request was longer, and postoperative pain was improved up to 6 h for proximal adductor canal block, compared to mid- and distal locations.

Conclusions

A proximal adductor canal injection location decreases opioid consumption and opioid-related side effects without compromising quadriceps strength compared to mid- and distal locations for adductor canal block in patients undergoing anterior cruciate ligament reconstruction.

Is continuous proximal adductor canal analgesia with a periarticular injection comparable to continuous epidural analgesia for postoperative pain after Total Knee Arthroplasty? A retrospective study

Background

The classic adductor canal block (ACB) is a regional technique that aims to introduce local anesthetic to the saphenous nerve as it traverses the adductor canal. It offers the benefit of preserved quadriceps strength, and is ideal for rehabilitation. Proximal ACB (PACB) allows the operator to place the block away from the surgical site, permitting preoperative placement. Our primary outcome was total opioid consumption; secondary outcomes included the highest numerical rating scale scores and total gait distance at the indicated time intervals.

Questions/purposes

We asked: 1) Does a Continuous Proximal ACB block with Periarticular knee injection (PACB) provide better analgesia than a Continuous Epidural (CSE)?; 2) Do PACB catheter patients do better with physical therapy compared to CSE patients?; 3) Are PACB patients discharged earlier than CSE patients?

Methods

With IRB approval we performed a retrospective chart review of patients who had underwent primary total knee arthroplasty between October 2015 and September 2016. The selected patients (n = 151) were divided into two groups: CSE group, 72 patients who received a continuous epidural catheter and the PACB group, 79 patients who received at PACB with Periarticular injection. The CSE group received a single-segment combined spinal epidural (CSE) in the operating room. The epidural catheter infusion was started with 0.1% ropivacaine at 8 mL/hour to 14 mL/hour during the post-operative period. The PACB group received a proximal adductor canal catheter with 20 ml of 0.5 % ropivacaine and maintained with ropivacaine 0.2% at 8 ml to 14 ml post operatively. Total opioid consumption, highest numeric rating scores and total gait distance travelled were recorded upon discharge from the PACU and completion of postoperative day (POD) 0, 1, and 2.

Results

We found that the median cumulative morphine consumption was significantly higher in the CSE group compared to the PACB group (194 (0-498) versus 126 (0-354) mg, p = 0.012), a difference that was most notable on POD 1 (84 (16-243) versus 60 (5-370) mg, p = 0.0001). Mean hospital length of stay was also shorter in the PACB group (2.6 ± 0.67 versus 3.0 ± 1.08 days, p = 0.01).

Conclusion

PACB group used significantly lower morphine consumption compared to the CSE group; they were better participants during physical therapy and achieved longer gait distances. The mean hospital length of stay was also shorter in the PACB group.

Implementation of the IPACK (Infiltration between the Popliteal Artery and Capsule of the Knee) block into a multimodal analgesic pathway for total knee replacement

Background

The Infiltration between the Popliteal Artery and Capsule of the Knee (IPACK) block is a new anesthesiologist- administered analgesic technique for controlling posterior knee pain that has not yet been well studied in total knee arthroplasty (TKA) patients. We compared pain outcomes in TKA patients before and after implementation of the IPACK with the hypothesis that patients receiving IPACK blocks will report lower pain scores on postoperative day (POD) 0 than non-IPACK patients.

Methods

With Institutional Review Board approval, we retrospectively reviewed data for consecutive TKA patients by a single surgeon 4 months before (PRE) and after (POST) IPACK implementation. All TKA patients received adductor canal catheters and peri-operative multimodal analgesia. The primary outcome was pain on POD 0. Other outcomes were daily pain scores, opioid consumption, ambulation distance, length of stay, and adverse events within 30 days.

Results

Post-implementation, 48/50 (96%) of TKA patients received an IPACK block, and they were compared with 32 patients in the PRE group. On POD 0, the lowest pain score (median [10th–90th percentiles]) was significantly lower for the POST group compared to the PRE group (0 [0–4.3] vs. 2.5 [0–7]; P = 0.003). The highest patient-reported pain scores on any POD were similar between groups with no differences in other outcomes.

Conclusions

Within a multimodal analgesic protocol, addition of IPACK blocks decreased the lowest pain scores on POD 0. Although other outcomes were unchanged, there may be a role for new opioid-sparing analgesic techniques, and changing clinical practice change can occur rapidly.

Lower extremity regional anesthesia: essentials of our current understanding

The advent of ultrasound guidance has led to a renewed interest in regional anesthesia of the lower limb. In keeping with the American Society of Regional Anesthesia and Pain Medicine's ongoing commitment to provide intensive evidence-based education, this article presents a complete update of the 2005 comprehensive review on lower extremity peripheral nerve blocks. The current review article strives to (1) summarize the pertinent anatomy of the lumbar and sacral plexuses, (2) discuss the optimal approaches and techniques for lower limb regional anesthesia, (3) present evidence to guide the selection of pharmacological agents and adjuvants, (4) describe potential complications associated with lower extremity nerve blocks, and (5) identify informational gaps pertaining to outcomes, which warrant further investigation.

The analgesic efficacy of the continuous adductor canal block compared to continuous intravenous fentanyl infusion with a single-shot adductor canal block in total knee arthroplasty: a randomized controlled trial

Background

The adductor canal block (ACB) is an effective intervention for postoperative analgesia following total knee arthroplasty (TKA). However, the ideal ACB regimen has not yet been established. We compared the analgesic effects between a continuous ACB group and fentanyl-based intravenous patient-controlled analgesia (IV-PCA) with a single-shot ACB group.

Methods

Patients who underwent TKA were randomly allocated to either a continuous ACB group (Group CACB) or IV-PCA with a single-shot ACB group (Group IVACB). Before the surgery, ultrasound guided ACB with 0.5% ropivacaine 20 cc was provided to all patients. Before skin incision, the infusion system (0.2% ropivacaine through an adductor canal catheter in group CACB vs. intravenous fentanyl in group IVACB) was connected. The postoperative pain severity; the side effects of local anesthetics and opioids; administration of rescue analgesics and anti-emetics; and sensorimotor deficits were measured.

Results

Postoperative pain severity was significantly higher in the IVACB group at 30 min, 4 h, 24 h, and 48 h after surgery. The averages and standard deviations (SD) of the NRS score of postoperative pain were 0.14 ± 0.37, 4.57 ± 2.37, 6.00 ± 1.63, and 4.28 ± 1.49, respectively in the IVACB group. Rescue analgesic requirements and quadriceps muscle strength were not statistically different between the groups throughout the postoperative period. Moreover, rescue antiemetic requirements were higher in group IVACB than group CACB.

Conclusions

In this study, the continuous ACB provided superior analgesia and fewer side effects without any significant motor deficit than the IV-PCA with a single-shot ACB.

A Randomized Comparison of Pain Control and Functional Mobility between Proximal and Distal Adductor Canal Blocks for Total Knee Replacement

Background:

Adductor canal blocks (ACBs) have become a popular technique for postoperative pain control in total knee arthroplasty patients. Proximal and distal ACB have been compared previously, but important postoperative outcomes have yet to be assessed.

Aims:

The primary objective of this study is to compare postoperative analgesia between proximal and distal ACB. Secondary outcomes include functional mobility, length of stay (LOS), and adverse events.

Settings and Design:

This study was a single-center, assessor-blinded, randomized trial.

Subjects and Methods:

Fifty-seven patients were randomly assigned to receive a proximal (n = 28) or distal (n = 29) ACB. A 20 mL bolus of 5 mg/mL ropivacaine was injected at the respective location followed by 2.0 mg/mL ropivacaine infusion for 24 h.

Statistical Analysis:

The primary outcome was intra- and postoperative 24-h opioid consumption in intravenous (IV) morphine equivalents. Secondary outcomes include percentage change in timed “Up and Go” (TUG) times, LOS, and average postoperative pain scores. Continuous variables were compared using Student's t-test.

Results:

The mean (±standard deviation) 24-h intra-and postoperative opioid consumption showed no difference between the proximal and distal groups (39.72 ± 23.6 and 41.28 ± 19.6 mg IV morphine equivalents, respectively, P = 0.793). There was also no significant difference in the median [minimum, maximum] percentage change in TUG times relative to preoperative performance comparing proximal and distal ACB (334.0 [131, 1084] %-change and 458.5 [169, 1696] %-change, respectively, P = 0.130). In addition, there were no differences in postoperative pain scores or LOS.

Conclusions:

ACB performed at either proximal or distal locations shows no difference in postoperative pain measured by opioid consumption or pain scores. Better TUG performance seen in the proximal group was not statistically significant but might represent a clinically important difference in functional mobility.

Durability of the Viabahn stent graft after axillary artery pseudoaneurysm exclusion

Pseudoaneurysm formation caused by iatrogenic arterial injury during a regional anesthetic block is a rare complication. We report a case of a 56-year-old male patient who developed an axillary artery pseudoaneurysm caused by brachial plexus block performed for an upper extremity dialysis access operation. Successful repair of this pseudoaneurysm was achieved with endovascular stent graft exclusion. The repaired axillary artery with the stent graft remained patent after 10 years of follow-up. The successful long-term patency of this treatment and a strategy to potentially avoid this complication are discussed.

Virtual reality distraction decreases routine intravenous sedation and procedure-related pain during preoperative adductor canal catheter insertion: a retrospective study

Background

Virtual reality (VR) distraction is a nonpharmacological method to prevent acute pain that has not yet been thoroughly explored for anesthesiology. We present our experience using VR distraction to decrease routine intravenous sedation for patients undergoing preoperative perineural catheter insertion.

Methods

This 1-month quality improvement project involved all elective unilateral primary total knee arthroplasty patients who received a preoperative adductor canal catheter. Clinical data were analyzed retrospectively. For the first half of the month, all patients received usual care; intravenous sedation was administered at the discretion of the regional anesthesiologist. For the second half of the month, patients were offered VR distraction with intravenous sedation upon request. The primary outcome was fentanyl dosage; other outcomes included midazolam dosage, procedure-related pain, procedural time, and blood pressure changes.

Results

Seven patients received usual care and seven used VR. In the VR group, 1/7 received intravenous sedation versus 6/7 who received usual care (P = 0.029). The fentanyl dose was lower (median [10th–90th percentiles]) in the VR group (0 [0–20] µg) versus the non-VR group (50 [30–100] µg; P = 0.008). Midazolam use was lower in the VR group (0 [0–0] mg) than in the non-VR group (1 [0–1] mg; P = 0.024). Procedure-related pain was lower in the VR group (1 [1–4] NRS) versus the non-VR group (3 [2–6] NRS; P = 0.032). There was no difference in other outcomes.

Conclusions

VR distraction may provide an effective nonpharmacological alternative to intravenous sedation for the ultrasound-guided placement of certain perineural catheters.

The Risk of Falls After Total Knee Arthroplasty with the Use of a Femoral Nerve Block Versus an Adductor Canal Block: A Double-Blinded Randomized Controlled Study

BACKGROUND

Adductor canal block (ACB) has emerged as an appealing alternative to femoral nerve block (FNB) that produces a predominantly sensory nerve block by anesthetizing the saphenous nerve. Studies have shown greater quadriceps strength preservation with ACB compared with FNB, but no advantage has yet been shown in terms of fall risk. The Tinetti scale is used by physical therapists to assess gait and balance, and total score can estimate a patient's fall risk. We designed this study to test the primary hypothesis that FNB results in a greater proportion of "high fall risk" patients postoperatively using the Tinetti score compared with ACB.

METHODS

After institutional review board approval, informed written consent to participate in the study was obtained. Patients undergoing primary unilateral total knee arthroplasty were eligible for enrollment in this double-blind, randomized trial. Patients received either an ACB or FNB (20 mL of 0.5% ropivacaine) with catheter placement (8 mL/h of 0.2% ropivacaine) in the setting of multimodal analgesia. Continuous infusion was stopped in the morning of postoperative day (POD)1 before starting physical therapy (PT). On POD1, PT assessed the primary outcome using the Tinetti score for gait and balance. Patients were considered to be at high risk of falling if they scored <19. Secondary outcomes included manual muscle testing of the quadriceps muscle strength, Timed Up and Go (TUG) test, and ambulation distance on POD1 and POD2. The quality of postoperative analgesia and the quality of recovery were assessed with American Pain Society Patient Outcome Questionnaire Revised and Quality of Recovery-9 questionnaire, respectively.

RESULTS

Sixty-two patients were enrolled in the study (31 ACB and 31 FNB). No difference was found in the proportion of "high fall risk" patients on POD1 (21/31 in the ACB group versus 24/31 in the FNB group [P = 0.7]; relative risk, 1.14 [95% confidence interval, 0.84-1.56]) or POD2 (7/31 in the ACB versus 14/31 in the FNB group [P = 0.06]; relative risk, 2.0 [95% confidence interval, 0.94-4.27]). The average distance of ambulation during PT and time to up and go were similar on POD1 and POD2. Manual muscle testing grades were significantly higher on POD1 in the ACB group when compared with that in the FNB (P = 0.001) (Wilcoxon-Mann-Whitney odds, 2.25 [95% confidence interval, 1.35-4.26]). There were no other differences in postoperative outcomes.

CONCLUSIONS

ACB results in greater preservation of quadriceps muscle strength. Although we did not detect a significant reduction in fall risk when compared with FNB, based on the upper limit of the relative risk, it may very well be present. Further study is needed with a larger sample size.

Adductor Canal Block Provides Noninferior Analgesia and Superior Quadriceps Strength Compared with Femoral Nerve Block in Anterior Cruciate Ligament Reconstruction

BACKGROUND

By targeting the distal branches of the femoral nerve in the mid-thigh, the adductor canal block (ACB) can preserve quadriceps muscle strength while providing analgesia similar to a conventional femoral nerve block (FNB) for inpatients undergoing major knee surgery. In this randomized, double-blind, noninferiority trial, the authors hypothesized that ACB provides postoperative analgesia that is at least as good as FNB while preserving quadriceps strength after outpatient anterior cruciate ligament reconstruction.

METHODS

A total of 100 patients were randomized to receive ACB or FNB with 20 ml ropivacaine 0.5% (with epinephrine). The authors sequentially tested the joint hypothesis that ACB is noninferior to FNB for cumulative oral morphine equivalent consumption and area under the curve for pain scores during the first 24 h postoperatively and also superior to FNB for postblock quadriceps maximal voluntary isometric contraction.

RESULTS

The authors analyzed 52 and 48 patients who received ACB and FNB, respectively. Compared with preset noninferiority margins, the ACB-FNB difference (95% CI) in morphine consumption and area under the curve for pain scores were -4.8 mg (-12.3 to 2.7) (P = 0.03) and -71 mm h (-148 to 6) (P < 0.00001), respectively, indicating noninferiority of ACB for both outcomes. The maximal voluntary isometric contraction for ACB and FNB at 45 min were 26.6 pound-force (24.7-28.6) and 10.6 pound-force (8.3-13.0) (P < 0.00001), respectively, indicating superiority of ACB.

CONCLUSION

Compared with FNB, the study findings suggest that ACB preserves quadriceps strength and provides noninferior postoperative analgesia for outpatients undergoing anterior cruciate ligament reconstruction.

Can bedside patient-reported numbness predict postoperative ambulation ability for total knee arthroplasty patients with nerve block catheters?

BACKGROUND

Adductor canal catheters offer advantages over femoral nerve catheters for knee replacement patients because they produce less quadriceps muscle weakness; however, applying adductor canal catheters in bedside clinical practice remains challenging. There is currently no patient-reported outcome that accurately predicts patients' physical function after knee replacement. The present study evaluates the validity of a relatively new patient-reported outcome, i.e., a numbness score obtained using a numeric rating scale, and assesses its predictive value on postoperative ambulation.

METHODS

We conducted a retrospective cohort study pooling data from two previously-published clinical trials using identical research methodologies. Both studies recruited patients undergoing knee replacement; one studied adductor canal catheters while the other studied femoral nerve catheters. Our primary outcome was patient-reported numbness scores on postoperative day 1. We also examined postoperative day 1 ambulation distance and its association with postoperative numbness using linear regression, adjusting for age, body mass index, and physical status.

RESULTS

Data from 94 subjects were included (femoral subjects, n = 46; adductor canal subjects, n = 48). Adductor canal patients reported decreased numbness (median [10(th)-90(th) percentiles]) compared to femoral patients (0 [0-5] vs. 4 [0-10], P = 0.001). Adductor canal patients also ambulated seven times further on postoperative day 1 relative to femoral patients. There was a significant association between postoperative day 1 total ambulation distance and numbness (Beta = -2.6; 95% CI: -4.5, -0.8, P = 0.01) with R(2) = 0.1.

CONCLUSIONS

Adductor canal catheters facilitate improved early ambulation and produce less patient-reported numbness after knee replacement, but the correlation between these two variables is weak.

Discharge Readiness after Tricompartment Knee Arthroplasty

Background:

The authors conducted a randomized, controlled, parallel-arm, superiority study to test the hypothesis that a continuous adductor canal block decreases the time to attain four discharge criteria compared with a continuous femoral nerve block after tricompartment knee arthroplasty.

Methods:

Subjects undergoing tricompartment knee arthroplasty were randomized using computer-generated lists to either an adductor canal or femoral perineural catheter (3-day ropivacaine 0.2% infusion) in an unmasked manner. The primary outcome was the time to attain four criteria: (1) adequate analgesia; (2) intravenous opioids independence; (3) ability to stand, walk 3 m, return, and sit down; and (4) ambulate 30 m.

Results:

Subjects with an adductor canal catheter (n = 39) reached all four criteria in a median of 55 h (interquartile, 42 to 63 h) compared with 61 h (49 to 69 h) for those with a femoral catheter (n = 41; 95% CI, −13 to 1 h; P = 0.12). The percentage of subjects who reached the two mobilization criteria on postoperative days 1 and 2 were 72 and 95% for those with an adductor canal catheter (n = 39), but only 27 and 76% in subjects with a femoral catheter (n = 41; both P &lt; 0.001). Differences in pain scores at rest and intravenous opioid requirements were minimal, but femoral infusion improved dynamic analgesia (P = 0.01 to 0.02).

Conclusion:

Compared with a continuous femoral nerve block, a continuous adductor canal block did not appreciably decrease the time to overall discharge readiness even though it did decrease the time until adequate mobilization, primarily because both groups experienced similar analgesia and intravenous opioid requirements that—in most cases—exceeded the time to mobilization.