Continuous Saphenous Nerve Block as Supplement to Single-Dose Local Infiltration Analgesia for Postoperative Pain Management After Total Knee Arthroplasty:

Defining the Location of the Adductor Canal Using Ultrasound

Background and Objectives

The precise location of the adductor canal remains controversial among anesthesiologists. In numerous studies of the analgesic effect of the so-called adductor canal block for total knee arthroplasty, the needle insertion point has been the midpoint of the thigh, determined as the midpoint between the anterior superior iliac spine and base of patella. “Adductor canal block” may be a misnomer for an approach that is actually an injection into the femoral triangle, a “femoral triangle block.” This block probably has a different analgesic effect compared with an injection into the adductor canal. We sought to determine the exact location of the adductor canal using ultrasound and relate it to the midpoint of the thigh.

Methods

Twenty-two volunteers were examined using ultrasound. The proximal end of the adductor canal was identified where the medial border of the sartorius muscle intersects the medial border of the adductor longus muscle. The distal end of the adductor canal is the adductor hiatus, which was also visualized ultrasonographically.

Results

The mean distance from the anterior superior iliac spine to the midpoint of the thigh was 22.9 cm (range, 20.3–24.9 cm). The mean distance from the anterior superior iliac spine to the proximal end of the adductor canal was 27.4 cm (range, 24.0–31.4 cm). Consequently, the mean distance from the midpoint of the thigh to the proximal end of the adductor canal was 4.6 cm (range, 2.3–7.0 cm).

Conclusions

In all volunteers, the midpoint of the thigh was proximal to the beginning of the adductor canal, suggesting that an injection performed at this level is in fact a femoral triangle block.

A Systematic Review of Postoperative Pain Outcome Measurements Utilised in Regional Anesthesia Randomized Controlled Trials

INTRODUCTION

Regional anesthesia is a rapidly growing subspecialty. There are few published meta-analyses exploring pain outcome measures utilised in regional anesthesia randomized controlled trials (RCTs), which may be due to heterogeneity in outcomes assessed. This systematic review explores postoperative pain outcomes utilised in regional anesthesia RCTs.

METHODS

A literature search was performed using three databases (Medline, Embase, and CINAHL). Regional anesthesia RCTs with postoperative pain as a primary outcome were included if written in English and published in one of the top 20 impact factor journals between 2005 and 2017. Study quality was assessed using the Cochrane Collaboration's tool for assessing risk of bias.

RESULTS

From the 31 included articles, 15 different outcome measures in total were used to assess postoperative pain. The most commonly (16/31) used outcome measures were verbal numerical grading of pain out of 10, total opioid consumption, and visual analogue scale 10 cm (VAS). The need for analgesia was used as an outcome measure where studies did not use a pain rating score. Ten studies reported pain scores on activity and 27/31 studies utilised ≥2 pain outcomes. Time of measurement of pain score also varied with a total of 51 different time points used in total.

CONCLUSION

Analysis of the articles demonstrated heterogeneity and inconsistency in choice of pain outcome and time of measurement within regional anesthesia studies. Identification of these pain outcomes utilised can help to create a definitive list of core outcomes, which may guide future researchers when designing such studies.

Adductor Canal Block Compared with Periarticular Bupivacaine Injection for Total Knee Arthroplasty: A Prospective Randomized Trial

BACKGROUND

In the last decade, the widespread use of regional anesthesia in total knee arthroplasty has led to improvements in pain control, more rapid functional recovery, and reductions in the length of the hospital stay. The aim of this study was to compare the efficacy of adductor canal blocks (ACB) and periarticular anesthetic injections (PAI), both with bupivacaine, for pain management in total knee arthroplasty.

METHODS

One hundred and fifty-five patients undergoing primary total knee arthroplasty under spinal anesthesia were randomized to 1 of 3 groups: ACB alone (15 mL of 0.5% bupivacaine), PAI alone (50 mL of 0.25% bupivacaine with epinephrine), and ACB+PAI. The primary outcome in this study was the visual analog scale (VAS) pain score in the immediate postoperative period. Secondary outcomes included postoperative opioid use, activity level during physical therapy, length of hospital stay, and knee range of motion.

RESULTS

The mean VAS pain score was significantly higher after use of ACB alone, compared with the score after use of ACB+PAI, on postoperative day 1 (POD1) (3.9 versus 3.0, p = 0.04) and POD3 (4.2 versus 2.0, p = 0.02). Total opioid consumption through POD3 was significantly higher when ACB alone had been used (131 morphine equivalents [ME]) compared with PAI alone (100 ME, p = 0.02) and ACB+PAI (98 ME, p = 0.02). Opioid consumption in the ACB-alone group was significantly higher than that in the ACB+PAI group on POD2 and POD3 and significantly higher than that in the PAI-alone group on POD2. There was no significant difference in opioid consumption between the patients treated with PAI alone and those who received ACB+PAI. The activity level during physical therapy on POD0 was significantly lower after use of ACB alone (26 steps) than after use of PAI alone (68 steps, p < 0.001) or ACB+PAI (65 steps, p < 0.001).

CONCLUSIONS

This randomized controlled clinical trial demonstrated significantly higher pain scores and opioid consumption after total knee arthroplasty done with an ACB and without PAI, suggesting that ACB alone is inferior for perioperative pain control. There were no significant differences between PAI alone and ACB+PAI with regard to pain or opioid consumption.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Postoperative continuous adductor canal block for total knee arthroplasty improves pain and functional recovery: A randomized controlled clinical trial

STUDY OBJECTIVE

Investigate the use of a postoperative continuous adductor canal block (cACB) after epidural analgesia to decreases opioid consumption and improve visual analog scale (VAS) scores compared to a sham catheter.

DESIGN

Double-blinded randomized placebo-controlled trial.

SETTING

Inpatient setting in tertiary care teaching hospital with outpatient follow-up.

PATIENTS

One-hundred and sixty-five subjects (cACB n = 82 and sham catheter n = 83) with end-stage degenerative joint disease undergoing elective unilateral total knee arthroplasty.

INTERVENTIONS

Patients were block randomized to receive a cACB or sham catheter. An epidural catheter was placed preoperatively and discontinued on postoperative day 1. Patients then received a cACB with bupivacaine or sham catheter which remained for the duration of the hospitalization.

MEASUREMENTS

Primary outcome was total opioid consumption. Secondary outcomes included VAS scores, knee range of motion (ROM), ambulation distance, and WOMAC scores.

MAIN RESULTS

Seventy patients completed the study (cACB n = 38 and sham catheter n = 32). Compared to sham catheter, in the first 20 h after placement of a cACB, patients used 22.5 mg less opioid (95% CI: -43.1 to -1.94 mg, P = 0.03). VAS score area under the curve decreased 7.8 mm (95% CI: -15.5 - -0.058 mm, P = 0.04) with a cACB. At 3-week follow-up, WOMAC scores were significantly improved with the cACB with a mean difference of 8.72 (95% CI: -17.3 to -0.11, P = 0.04). There were no statistically significant differences in secondary outcomes on postoperative day 2. Paired outcomes at 6 weeks compared to baseline ROM, showed significant improvement in knee ROM with a cACB (mean difference 11.77°, 95% CI: 3.1-20.5°, P = 0.01).

CONCLUSION

A postoperative cACB after total knee arthroplasty significantly reduces total opioid consumption and pain scores compared to sham catheter. Ambulatory ability was not affected and patients recovered function earlier. ClinicalTrials.govNCT02121392.

Does Adductor Canal Block Have a Synergistic Effect with Local Infiltration Analgesia for Enhancing Ambulation and Improving Analgesia after Total Knee Arthroplasty?

Purpose

We compared a single-injection adductor canal block (ACB) with or without local infiltration analgesia (LIA) for accelerating functional recovery and reducing postoperative pain after total knee arthroplasty (TKA).

Materials and Methods

Sixty-two patients undergoing TKA with simple spinal analgesia and ACB were randomized to receive either LIA (group A+L) or placebo LIA (group A). Postoperative visual analog scale (VAS) score for pain, Timed Up and Go (TUG) test and quadriceps strength, total dosage of rescue analgesia, time to first rescue analgesia, and adverse events were serially evaluated from postoperative day 1 to 3 months.

Results

There were no differences between both groups in pre- and postoperative VAS, TUG test, quadriceps strength 2 days, 3 days, 2 weeks, 6 weeks, and 3 months postoperatively. There were no differences in Knee Society clinical and function scores at 6 months and 1 year. However, group A+L had a significantly longer time for postoperative rescue analgesia (491 minutes vs. 143 minutes, p=0.04) with less patients requiring rescue analgesia during 6 hours after surgery (16.7% vs. 43.3%, p=0.024). Both groups had similarly high rates of patient satisfaction with low adverse event rates.

Conclusions

Combined ACB and LIA in TKA enhanced early ambulation with reduced and delayed rescue analgesia.

Comparison of Adductor Canal Block Versus Local Infiltration Analgesia on Postoperative Pain and Functional Outcome after Total Knee Arthroplasty: A Randomized Controlled Trial

Introduction: Total knee arthroplasty (TKA) is associated with intense postoperative pain for which effective analgesia is essential to facilitate early postoperative recovery. Adductor canal block (ACB) and local infiltration analgesia (LIA) have become increasingly involved in postoperative pain management after TKA. We aimed to compare their efficacy and outcomes in patients undergoing TKA.

Materials and Methods: Sixty patients undergoing unilateral TKA were randomized to receive either postoperative single-injection ACB (Group A) or LIA (Group L) during the operation. All patients received spinal anaesthesia. Primary outcome was total morphine consumption over postoperative 24 hours. Visual analog pain scale, time to first and total dosage of rescue analgesia, performance-based evaluations [timed-up and go (TUG) test, quadriceps strength], side-effects, length of hospital stay and patient satisfaction were measured.

Results: Fifty-seven patients were available for analysis. Median total morphine consumption over 24 and 48 postoperative hours of Group A were significantly less than Group L (6/10 mg vs 13/25 mg, p, 0.008 and 0.001, respectively). Similarly, Group A had significantly lower VAS at postoperative 6, 12 and 18 hours, VAS at ambulation on postoperative (POD) 1-3, better TUG tests on POD 2 and during POD 3 than those of Group L. However, quadriceps strength and patient satisfaction were not different between both groups.

Conclusion: Patients undergoing TKA with single-injection ACB required less postoperative opioids than those with LIA. Furthermore, multimodal analgesia using ACB provided better postoperative analgesia, as well as performance-based activities, than those with LIA.

A comparative analysis of femoral nerve block with adductor canal block following total knee arthroplasty: A systematic literature review

Background:

Patients undergoing total knee arthroplasty suffer from moderate-to-severe postoperative pain resulting in immobility-related complications and prolonged hospitalization. Femoral nerve block is associated with reduction in the quadriceps strength and increasing incidence of falls. Adductor canal block has been shown to be as effective as femoral nerve block without causing quadriceps weakness.

Objectives:

To compare outcomes of studies comparing adductor canal block and femoral nerve block in patients undergoing primary total knee arthroplasty.

Data Sources:

Original articles, published between July 2013 and April 2017, comparing the above interventions.

Study Eligibility Criteria, Participants, and Interventions:

Comparison of outcome measures of all original articles shortlisted by the PUBMED and Google Scholar databases search using key words, “adductor canal block; femoral nerve block; total knee arthroplasty; total knee replacement.”

Study Appraisal and Synthesis Methods:

The primary outcome measures reviewed were: pain scores; interventional failure; post-operative opioid consumption; patient fall or near fall during postoperative rehabilitation; and length of stay.

Results:

The opioid consumption was found to be comparable with both the interventions on the first and second postoperative day. Patients administered adductor canal block had better quadriceps power, longer ambulation distance, and shorter length of hospital stay.

Limitations:

Of the studies reviewed five were retrospective and thus data quality amongst the studies may have been compromised.

Conclusions and Implications of Key Findings:

Mobilization and ambulation, which are both important for recovery after total knee arthroplasty are both inhibited less by adductor canal block.

Adductor Canal Block Versus Femoral Nerve Block for Analgesia After Total Knee Arthroplasty: A Systematic Review and Meta-analysis

OBJECTIVES

The efficacy and safety of adductor canal block (ACB) as compared with femoral nerve block (FNB) for postoperative pain management in total knee arthroplasty (TKA) remains controversial. We therefore performed a meta-analysis of randomized-controlled trials (RCTs) to compare ACB with FNB in TKA.

MATERIALS AND METHODS

Databases, including Pubmed, Medline, Embase, Web of Science, and Cochrane library were searched to identify RCTs comparing ACB with FNB for pain management in patients undergoing TKA. The primary outcomes included pain score with rest or activity and opioid consumption. Secondary outcomes were mobilization ability, quadriceps strength and grade, length of hospital stay, and complications (nausea or vomiting).

RESULTS

A total of 573 TKAs in 514 patients from 7 RCTs were included in the meta-analysis. Two studies with 155 TKAs reported the mobilization ability assessed by Timed Up and Go Test. The ACB patients performed significantly faster than the FNB patients in the early postoperative period (mean difference=-5.08; 95% confidence interval, -6.03 to -4.13; P<0.00001). The subgroup analysis showed that the outcomes of pain, morphine consumption, quadriceps strength, and length of hospital stay in single shot and continuous subgroups were not statistically different between the 2 groups (P>0.05).

DISCUSSION

ACB may achieve faster mobilization ability recovery for patients after TKA without a reduction in analgesia when compared with FNB in the early postoperative period. However, due to the variations in the included studies, additional studies are needed to validate these conclusions.

Ultrasound-guided genicular nerve block for pain control after total knee replacement: Preliminary case series and technical note

INTRODUCTION

Total knee arthroplasty (TKA) is an operation with moderate to severe postoperative pain. The Fast-Track models employ local infiltration techniques with anaesthetics at high volumes (100-150ml). We proposed a genicular nerve block with low volume of local anaesthetic. The aim of our study is to evaluate the periarticular distribution of these blocks in a fresh cadaver model and to describe the technique in a preliminary group of patients submitted to TKA.

MATERIALS AND METHODS

In the anatomical phase, 4 genicular nerves (superior medial, superior lateral, inferior medial and inferior lateral) were blocked with 4ml of local anaesthetic with iodinated contrast and methylene blue in each (16ml in total). It was performed on a fresh cadaver and the distribution of the injected medium was evaluated by means of a CT-scan and coronal anatomical sections on both knees. The clinical phase included 12 patients scheduled for TKA. Ultrasound-guided block of the 4 genicular nerves was performed preoperatively and their clinical efficacy evaluated by assessing pain after the reversal of the spinal block and at 12h after the block. Pain was measured using the numerical scale and the need for rescue analgesia was evaluated.

RESULTS

A wide periarticular distribution of contrast was observed by CT-scan, which was later evaluated in the coronal sections. The distribution followed the joint capsule without entering the joint, both in the femur and in the tibia. The pain after the reversal of the subarachnoid block was 2±1, requiring rescue analgesia in 42% of the patients. At 12h, the pain according to the numerical scale was 4±1, 33% required rescue analgesia.

CONCLUSION

The administration of 4ml of local anaesthetic at the level of the 4 genicular nerves of the knee produces a wide periarticular distribution. Our preliminary data in a series of 12 patients undergoing TKA seems to be clinically effective. Nevertheless, extensive case series and comparative studies with local infiltration techniques with anaesthetics are needed to support these encouraging results.

Continuous adductor canal block added to local infiltration analgesia (LIA) after total knee arthroplasty has no additional benefits on pain and ambulation on postoperative day 1 and 2 compared with LIA alone

Background and purpose - The additional effects of a continuous adductor canal block (ACB) compared with a single-dose local infiltration anesthesia (LIA) after total knee arthroplasty (TKA) has not been widely researched. Both methods have good effect individually. We hypothesized that a continuous ACB added to a single-dose LIA would lower pain scores while ambulating on postoperative day 1 (POD1) and postoperative day 2 (POD2). Patients and methods - 69 participants were included in this prospective, randomized, double-blind, placebo-controlled trial. The TKA was performed under spinal analgesia and every participant was given single-dose LIA intraoperatively. Patients were then randomized into 2 groups, treatment group receiving 0.2% ropivacaine and control group receiving normal saline. First a 20 mL bolus was given into the adductor canal and 4 hours later a continuous flow at 6 mL/h was initiated for 2 postoperative days through a catheter placed in the adductor canal. Results - Worst pain score during movement of the operated knee on POD1 and POD2 was similar between the groups. No other ambulation tests done on POD1 and POD2 showed any statistically significant difference. Morphine consumption on the day of surgery, POD1 and POD2 was similar between the groups. Interpretation - The results indicate no benefit of continuous infusion ACB added to a single-dose LIA compared with LIA alone on pain while ambulating on POD1 and POD2. Furthermore, the ACB showed no superiority in ambulation ability on the 2 postoperative days.

A Three-arm Randomized Clinical Trial Comparing Continuous Femoral Plus Single-injection Sciatic Peripheral Nerve Blocks versus Periarticular Injection with Ropivacaine or Liposomal Bupivacaine for Patients Undergoing Total Knee Arthroplasty

BACKGROUND

Multimodal analgesia is standard practice for total knee arthroplasty; however, the role of regional techniques in improved perioperative outcomes remains unknown. The authors hypothesized that peripheral nerve blockade would result in lower pain scores and opioid consumption than two competing periarticular injection solutions.

METHODS

This three-arm, nonblinded trial randomized 165 adults undergoing unilateral primary total knee arthroplasty to receive (1) femoral catheter plus sciatic nerve blocks, (2) ropivacaine-based periarticular injection, or (3) liposomal bupivacaine-based periarticular injection. Primary outcome was maximal pain during postoperative day 1 (0 to 10, numerical pain rating scale) in intention-to-treat analysis. Additional outcomes included pain scores and opioid consumption for postoperative days 0 to 2 and 3 months.

RESULTS

One hundred fifty-seven study patients received peripheral nerve block (n = 50), ropivacaine (n = 55), or liposomal bupivacaine (n = 52) and reported median maximal pain scores on postoperative day 1 of 3, 4, and 4.5 and on postoperative day 0 of 1, 4, and 5, respectively (average pain scores for postoperative day 0: 0.6, 1.7, and 2.4 and postoperative day 1: 2.5, 3.5, and 3.7). Postoperative day 1 median maximal pain scores were significantly lower for peripheral nerve blockade compared to liposomal bupivacaine-based periarticular injection (P = 0.016; Hodges-Lehmann median difference [95% CI] = -1 [-2 to 0]). After postanesthesia care unit discharge, postoperative day 0 median maximal and average pain scores were significantly lower for peripheral nerve block compared to both periarticular injections (ropivacaine: maximal -2 [-3 to -1]; P < 0.001; average -0.8 [-1.3 to -0.2]; P = 0.003; and liposomal bupivacaine: maximal -3 [-4 to -2]; P < 0.001; average -1.4 [-2.0 to -0.8]; P < 0.001).

CONCLUSIONS

Ropivacaine-based periarticular injections provide pain control comparable on postoperative days 1 and 2 to a femoral catheter and single-injection sciatic nerve block. This study did not demonstrate an advantage of liposomal bupivacaine over ropivacaine in periarticular injections for total knee arthroplasty.

Does Addition of Multimodal Periarticular Analgesia to Adductor Canal Block Improve Lengths of Stay, Pain, Discharge Status, and Opioid Use After Total Knee Arthroplasty?

BACKGROUND

Postoperative pain after total knee arthroplasty (TKA) can be burdensome. Multiple methods of pain control have been used, including adductor canal block (ACB) and multimodal periarticular analgesia (MPA). These two techniques have been studied have proven to be efficacious separately. The purpose of this study was to compare: (1) lengths of stay (LOS), (2) pain level, (3) discharge status, and (4) opioid use in TKA patients who received ACB alone vs patients who received ACB and MPA.

METHODS

A single surgeon database was reviewed for patients who had a TKA between January 2015 and April 2016. Patients who received ACB with or without MPA were included. This yielded 127 patients who had a mean age of 63 years. Patients were grouped into having received ACB alone (n = 52) and having received ACB and MPA (n = 75). Patient records were reviewed to obtain demographic and end point data (LOS, pain, discharge status, and opioid use). Student t test and chi-squared test were used to compare continuous and categorical variables respectively.

RESULTS

There were no significant difference in mean LOS (P = .934), pain level (P = .142), discharge status (P = .077), or total opioid use (P = .708) between the 2 groups.

CONCLUSION

There was no significant difference in LOS, pain levels, discharge status, and opiate requirements between the 2 groups. ACB alone may be as effective as combined ACB and MPA in TKA patients for postoperative pain control. Larger prospective studies are needed to verify these findings and to improve generalization.

Postoperative Analgesia in Patients Undergoing Primary or Revision Knee Arthroplasty with Adductor Canal Block

Background

Multimodal analgesia featuring peripheral nerve blocks decreases postoperative pain for patients undergoing primary total knee arthroplasty (TKA). Many anesthesiologists and surgeons advocate for the use of adductor canal blocks (ACBs) for analgesia, which result in less weakness compared to femoral nerve blocks. Few data exist to guide analgesic management in total knee revision (TKR), considered to be more painful than primary TKA. We hypothesized that TKR patients with a continuous ACB would use more opioids than primary TKA patients who received the same analgesic regimen.

Methods

A retrospective study of 58 TKA and TKR patients who received ACBs in a multimodal protocol was conducted from 1/2014 to 3/2016. Exclusion criteria included patients who took ≥ 20 mg of morphine daily preoperatively. The primary outcome was 48-hour opioid consumption. Secondary outcomes included pain ratings, catheter boluses, and catheter infusion rate changes over 48 hours.

Results

For the primary outcome of 48-hour opioid consumption, there was no significant difference between groups. Postoperative pain ratings were not significantly different during the overall 48-hour time period. There were also no significant differences in catheter boluses and infusion rate changes. Least squares regression analysis revealed a positive correlation between number of previous knee surgeries and postoperative pain level.

Conclusions

Patients who underwent TKR with continuous ACB experienced a similar postoperative analgesic course as primary TKA patients. Within the TKR cohort, the number of previous revisions was positively associated with pain level. Larger prospective studies with TKR are needed to confirm these findings.

Postoperative pain treatment after total knee arthroplasty: A systematic review

INTRODUCTION

The aim of this systematic review was to document efficacy, safety and quality of evidence of analgesic interventions after total knee arthroplasty (TKA).

METHODS

This PRISMA-compliant and PROSPERO-registered review includes all-language randomized controlled trials of medication-based analgesic interventions after TKA. Bias was evaluated according to Cochrane methodology. Outcomes were opioid consumption (primary), pain scores at rest and during mobilization, adverse events, and length of stay. Interventions investigated in three or more trials were meta-analysed. Outcomes were evaluated using forest plots, Grading of Recommendations Assessment, Development and Evaluation (GRADE), L'Abbe Plots and trial sequential analysis.

RESULTS

The included 113 trials, investigating 37 different analgesic interventions, were characterized by unclear/high risk of bias, low assay sensitivity and considerable differences in pain assessment tools, basic analgesic regimens, and reporting of adverse events. In meta-analyses single and continuous femoral nerve block (FNB), intrathecal morphine, local infiltration analgesia, intraarticular injection of local anaesthetics, non-steroidal anti-inflammatory drugs, and gabapentinoids demonstrated significant analgesic effects. The 24-hour morphine-sparing effects ranged from 4.2 mg (CI: 1.3, 7.2; intraarticular local anaesthetics), to 16.6 mg (CI: 11.2, 22; single FNB). Pain relieving effects at rest at 6 hours ranged from 4 mm (CI: -10, 2; gabapentinoids), to 19 mm (CI: 8, 31; single FNB), and at 24 hours from 3 mm (CI: -2, 8; gabapentinoids), to 16 mm (CI: 8, 23; continuous FNB). GRADE-rated quality of evidence was generally low.

CONCLUSION

A low quality of evidence, small sample sizes and heterogeneity of trial designs prohibit designation of an optimal procedure-specific analgesic regimen after TKA.

Novel Regional Techniques for Total Knee Arthroplasty Promote Reduced Hospital Length of Stay: An Analysis of 106 Patients

BACKGROUND

Novel regional techniques, including the adductor canal block (ACB) and the local anesthetic infiltration between the popliteal artery and capsule of the knee (IPACK) block, provide an alternative approach for controlling pain following total knee arthroplasty (TKA). This study compared 3 regional techniques (femoral nerve catheter [FNC] block alone, FNC block with IPACK, and ACB with IPACK) on pain scores, opioid consumption, performance during physical therapy, and hospital length of stay in patients undergoing TKA.

METHODS

All patients had a continuous perineural infusion, either FNC block or ACB. Patients in the IPACK block groups also received a single injection 30-mL IPACK block of 0.25% ropivacaine. Pain scores and opioid consumption were recorded at postanesthesia care unit discharge and again at 8-hour intervals for 48 hours. Physical therapy performance was measured on postoperative days (POD) 1 and 2, and hospital length of stay was recorded.

RESULTS

We found no significant differences in the 3 groups with regard to baseline patient demographics. Although we observed no differences in pain scores between the 3 groups, opioid consumption was significantly reduced in the FNC with IPACK group. Physical therapy performance was significantly better on POD 1 in the ACB with IPACK group compared to the other 2 groups. Hospital length of stay was significantly shorter in the ACB with IPACK group.

CONCLUSION

This study demonstrated that an IPACK block reduced opioid consumption by providing effective supplemental analgesia following TKA compared to the FNC-only technique. ACB with IPACK provided equivalent analgesia and improved physical therapy performance, allowing earlier hospital discharge.

Combined adductor canal block with periarticular infiltration versus periarticular infiltration for analgesia after total knee arthroplasty

BACKGROUND

Both adductor canal block (ACB) and periarticular infiltration (PI) have been shown to reduce pain after total knee arthroplasty (TKA) without the motor blockade. However, the efficacy and safety of combined ACB with PI (ACB + PI) as compared to PI alone for analgesia after TKA remains controversial. We therefore performed a meta-analysis to compare the effects of ACB + PI with PI alone on pain controll after TKA.

METHODS

PubMed, Medline, Embase, Web of Science, and the Cochrane Library were searched to identify studies comparing ACB + PI with PI alone for TKA patients. The primary outcomes included pain score with rest or activity and morphine consumption. Secondary outcomes were distance walked, length of hospital stay, and postoperative complications. Relevant data were analyzed using RevMan v5.3.

RESULTS

Three studies involving 337 patients were included. Combined ACB with PI was associated with longer distances walked than PI alone (MD = 7.27, 95% CI: 0.43-14.12, P = 0.04) on postoperative day 1. The outcomes of pain, morphine consumption, length of hospital stay, and postoperative complications were not statistically different between the 2 groups (P > 0.05).

CONCLUSION

Our meta-analysis suggests that combined ACB with PI may achieve earlier ambulation for patients after TKA without a reduction in analgesia when compared to PI alone in the early postoperative period. There were no significant differences in morphine consumption, length of hospital stay, and postoperative complications between the 2 groups. However, owing to the variation of included studies, no firm conclusions can be drawn.

Intraoperative Adductor Canal Block for Augmentation of Periarticular Injection in Total Knee Arthroplasty: A Cadaveric Study

BACKGROUND

Function is often sacrificed for pain control after total knee arthroplasty. Motor-sparing blocks, including adductor canal block (ACB) and periarticular injection (PAI), have gained interest to address this compromise. Our study evaluates the anatomic feasibility, accuracy, and safety of intraoperative ACB as an adjunct to PAI by analyzing 3 different injection orientations and needle configurations.

METHODS

Eleven cadaveric knees underwent a standard medial parapatellar arthrotomy. Blunt dissection through the suprapatellar recess was performed. Using a 10-mL syringe, various colors of dyed liquid gelatin were injected toward the proximal and distal adductor canal (AC) using 3 needle configurations. Medial dissection of the knee for each specimen was performed. The position of each needle and location of injected dye was identified and described relative to the AC.

RESULTS

Accuracy of each injection orientation and/or needle configuration was different: 86% for a blunt needle in the distal AC, 57% for blunt needle in the proximal AC, and 14% for a spinal needle in the proximal AC. Puncture of the femoral artery was observed with the spinal needle 43% of the time and had the closest average proximity to the femoral artery with a distance of 5.9 mm. There were no vascular punctures using blunt needles, and the average distance from the femoral artery with proximal and distal orientation was 10.2 mm and 15.4 mm, respectively.

CONCLUSION

Intraoperative ACB augmentation of PAI appears to be anatomically feasible and safe. There was decreased accuracy and increased risk of vascular puncture using a 3.5-inch spinal needle. A blunt 1.5-inch needle directed toward the distal AC had the highest accuracy while minimizing vascular injury.

Opioid consumption in total knee arthroplasty patients: a retrospective comparison of adductor canal and femoral nerve continuous infusions in the presence of a sciatic nerve catheter

OBJECTIVE

To compare opioid consumption among patients who receive a continuous adductor canal block (ACB) versus continuous femoral nerve block (FB) for total knee arthroplasty analgesia in the presence of an intermittent sciatic nerve catheter (iSB).

DESIGN

Matched cohort retrospective study.

SETTING

Mayo Clinic, Jacksonville, FL.

PATIENTS

Ninety patient charts were included in this study: 45 patients with continuous ACB/iSB and 45 with continuous FB/iSB. Patients were matched according to mean preoperative opioid consumption and pain scores, BMI, age, and gender.

MEASUREMENTS

The primary outcome of the study was postoperative on-demand opioid consumption on postoperative days 0 (POD 0), 1 (POD 1), and 2 (POD 2). Secondary outcomes included postoperative Visual Analog Scale (VAS) scores for anterior and posterior knee pain, incidence of nausea and pruritus, need for intravenous rescue opioid, and need for catheter bolus by a physician.

MAIN RESULTS

On POD 0, mean opioid consumption in milligrams of oral morphine equivalent [mean±SD (95% CI)] was 43.98mg±33.36 (33.96, 54) in the ACB/iSB group vs 38.45mg±30.99 (29.14, 47.76) in the FB/iSB group, respectively (P=.42); on POD 1, 74.96mg±37.23 (63.78, 86.14) vs 72.40mg±62.34 (53.67, 91.13) (P=.81); on POD 2, 28.19mg±17.69 (22.87, 33.51) vs 31.84mg±23.09 (24.90, 38.78) (P=.40). On POD 1, median anterior knee VAS scores at rest were equivalent in both the ACB/iSB and FB/iSB groups (1 vs 1, respectively, P=.46); however, patients in the ACB/iSB group were more likely to have higher anterior knee pain scores with movement (4 vs 1, P=.002).

CONCLUSION

In the first 2 days after a total knee arthroplasty, opioid consumption in patients with continuous ACB/iSB was not significantly different from patients receiving continuous FB/iSB. Continuous adductor canal block appears to provide adequate analgesia when compared to continuous femoral blockade.

Use of a perineural coiled catheter at the sciatic nerve in dogs after tibial plateau levelling osteotomy - preliminary observations

The analgesic effects of peripheral nerve blocks can be prolonged with the placement of perineural catheters allowing repeated injections of local anaesthetics in humans. The objectives of this study were to evaluate the clinical suitability of a perineural coiled catheter (PCC) at the sciatic nerve and to evaluate pain during the early post-operative period in dogs after tibial plateau levelling osteotomy. Pre-operatively, a combined block of the sciatic and the femoral nerves was performed under sonographic guidance (ropivacaine 0.5%; 0.3 mL kg^-1 per nerve). Thereafter, a PCC was placed near the sciatic nerve. Carprofen (4 mg kg^-1 intravenously) was administered at the end of anaesthesia. After surgery, all dogs were randomly assigned to receive four injections of ropivacaine (group R; 0.25%, 0.3 mL kg^-1) or NaCl 0.9% (group C; 0.3 mL kg^-1) every 6 h through the PCC. Pain was assessed by use of a visual analogue scale (VAS) and a multi-dimensional pain score (4Avet) before surgery (T-1), for 390 min (T0, T30, T60, T120, T180, T240, T300, T360 and T390) as well as 1 day after surgery (Day 1). Methadone (0.1 mg kg^-1) was administered each time the VAS was ≥40 mm or the 4Avet was ≥5. At T390 dogs received buprenorphine (0.02 mg kg^-1). Data were compared using Mann-Whitney rank sum tests and repeated measures analysis of variance. Regardless of group allocation, 55% of dogs required methadone. VAS was significantly lower at T390 (P = 0.003), and at Day 1 (P = 0.002) and so was 4Avet at Day 1 (P = 0.012) in group R than in group C. Bleeding occurred in one dog at PCC placement and PCC dislodged six times of 47 PCCs placed. Minor complications occurred with PCC but allowed four repeated administrations of ropivacaine or saline over 24 h in 91.5% of the cases.

A Comparison of Single Shot Adductor Canal Block Versus Femoral Nerve Catheter for Total Knee Arthroplasty

The aim of this study was to compare perioperative analgesia provided by single-injection adductor canal block (ACB) to continuous femoral nerve catheter (FNC) when used in a multimodal pain protocol for total knee arthroplasty (TKA). A retrospective cohort study compared outcome data for 148 patients receiving a single-injection ACB to 149 patients receiving an FNC. The mean length of stay (LOS) in the ACB group was 2.67 (±0.56) and 3.01 days (±0.57) in the FNC group (P<0.0001). The median ambulatory distances for the adductor group were further than the femoral group for postoperative days 1 (P<0.0001) and 2 (P=0.01). Single-injection ACB offered similar pain control and earlier discharge compared to continuous FNC in patients undergoing TKA.

Analgesia for total knee arthroplasty: a meta-analysis comparing local infiltration and femoral nerve block

Patients frequently experience postoperative pain after a total knee arthroplasty; such pain is always challenging to treat and may delay the patient's recovery. It is unclear whether local infiltration or a femoral nerve block offers a better analgesic effect after total knee arthroplasty.We performed a systematic review and meta-analysis of randomized controlled trials to compare local infiltration with a femoral nerve block in patients who underwent a primary unilateral total knee arthroplasty. We searched Pubmed, EMBASE, and the Cochrane Library through December 2014. Two reviewers scanned abstracts and extracted data. The data collected included numeric rating scale values for pain at rest and pain upon movement and opioid consumption in the first 24 hours. Mean differences with 95% confidence intervals were calculated for each end point. A sensitivity analysis was conducted to evaluate potential sources of heterogeneity.While the numeric rating scale values for pain upon movement (MD-0.62; 95%CI: -1.13 to -0.12; p=0.02) in the first 24 hours differed significantly between the patients who received local infiltration and those who received a femoral nerve block, there were no differences in the numeric rating scale results for pain at rest (MD-0.42; 95%CI:-1.32 to 0.47; p=0.35) or opioid consumption (MD 2.92; 95%CI:-1.32 to 7.16; p=0.18) in the first 24 hours.Local infiltration and femoral nerve block showed no significant differences in pain intensity at rest or opioid consumption after total knee arthroplasty, but the femoral nerve block was associated with reduced pain upon movement.

Regional analgesia for improvement of long-term functional outcome after elective large joint replacement

BACKGROUND

Regional analgesia is more effective than conventional analgesia for controlling pain and may facilitate rehabilitation after large joint replacement in the short term. It remains unclear if regional anaesthesia improves functional outcomes after joint replacement beyond three months after surgery.

OBJECTIVES

To assess the effects of regional anaesthesia and analgesia on long-term functional outcomes 3, 6 and 12 months after elective major joint (knee, shoulder and hip) replacement surgery.

SEARCH METHODS

We performed an electronic search of several databases (CENTRAL, MEDLINE, EMBASE, CINAHL), and handsearched reference lists and conference abstracts. We updated our search in June 2015.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing regional analgesia versus conventional analgesia in patients undergoing total shoulder, hip or knee replacement. We included studies that reported a functional outcome with a follow-up of at least three months after surgery.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We contacted study authors for additional information.

MAIN RESULTS

We included six studies with 350 participants followed for at least three months. All of these studies enrolled participants undergoing total knee replacement. Studies were at least partially blinded. Three studies had a high risk of performance bias and one a high risk of attrition bias, but the risk of bias was otherwise unclear or low.Only one study assessed joint function using a global score. Due to heterogeneity in outcome and reporting, we could only pool three out of six RCTs, with range of motion assessed at three months after surgery used as a surrogate for joint function. All studies had a high risk of detection bias. Using the random-effects model, there was no statistically significant difference between the experimental and control groups (mean difference 3.99 degrees, 95% confidence interval (CI) - 2.23 to 10.21; P value = 0.21, 3 studies, 140 participants, very low quality evidence).We did not perform further analyses because immediate adverse effects were not part of the explicit outcomes of any of these typically small studies, and long-term adverse events after regional anaesthesia are rare.None of the included studies elicited or reported long-term adverse effects like persistent nerve damage.

AUTHORS' CONCLUSIONS

More high-quality studies are needed to establish the effects of regional analgesia on function after major joint replacement, as well as on the risk of adverse events (falls).

Femoral nerve block versus adductor canal block for postoperative pain control after anterior cruciate ligament reconstruction: A randomized controlled double blind study

Background:

The objective of this study was to evaluate the reliability of the postoperative pain control using adductor canal block (ACB) compared that using the femoral nerve block (FNB) in patients with anterior cruciate ligament reconstructions (ACLR).

Materials and methods:

One hundred and twenty-eight patients who had been scheduled to patellar graft ACLR were included in this double blind study, and were randomly allocated into two groups; group ACB and group FNB (64 patients each). All patients received general anesthesia. At the end of the surgery, patients in group FNB received a FNB and those in group ACB received an ACB. The postoperative pain (visual analog scale [VAS]) and muscle weakness were assessed in the postoperative care unit and every 6 h thereafter for 24 h. The total morphine requirements were also recorded.

Results:

Patients in group ACB had significantly higher VAS (at 18 h and 24 h), higher morphine consumption, but significantly less quadriceps weakness than those in group FNB.

Conclusion:

In patients with patellar graft ACLR, the ACB can maintain a higher quadriceps power, but with lesser analgesia compared with the FNB.

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.

Laparoscopic-Assisted Transversus Abdominis Plane Block for Postoperative Pain Control in Laparoscopic Ventral Hernia Repair: A Randomized Controlled Trial

BACKGROUND

Laparoscopic ventral hernia repair (LVHR) is associated with considerable postoperative pain. Transversus abdominis plane (TAP) blocks have proven effective in controlling postoperative pain in a variety of laparoscopic abdominal operations. To date, no studies have focused on TAP blocks in LVHR. Our goal was to assess whether TAP blocks reduce opioid requirements and pain scores after LVHR.

STUDY DESIGN

Patients undergoing LVHR were randomly assigned to receive a TAP block or placebo injection. The primary end points were cumulative opioid use at 1, 3, 6, 12, 18, and 24 hours postoperatively and pain scores recorded at 1 and 24 hours postoperatively.

RESULTS

Patients in the experimental TAP group (n = 52) and control group (n = 48) were comparable with respect to patient demographics and clinical characteristics. In the postanesthesia care unit, the TAP group had significantly lower pain scores than the control group (p < 0.05). Patients in the TAP group used less opioids than the control group at each time point assessed after 6 hours postoperatively (p < 0.05). There was no significant difference in pain scores at 24 hours postoperatively (p > 0.05).

CONCLUSIONS

Transversus abdominis plane blocks given during LVHR significantly decrease both short-term postoperative opioid use and pain experienced by patients.

The spread of injectate during saphenous nerve block at the adductor canal: a cadaver study

BACKGROUND

The spread of injectate during a saphenous nerve block at the adductor canal has not been clearly described.

METHODS

We examined the spread of 15 ml dyed injectate during ultrasound-guided saphenous nerve blocks at the adductor canal in 15 unembalmed cadavers' lower limbs followed by comparative dissections of the same limbs.

RESULTS

The spread of the injectates was determined by the fascial limits and the muscles surrounding the adductor canal. The anteromedial limit of the adductor canal (the roof) was found to be a continuous fascia, with a thin proximal part and a thicker distal part (the vastoadductor membrane) covering the canal from the apex of the femoral triangle to the adductor hiatus. The fascial limits of the adductor canal formed a conduit around the femoral neurovascular bundle. The dyed aqueous injectate spread throughout the entire adductor canal to the femoral triangle and reached 1-2 cm into the popliteal fossa. Injections superficial to the adductor canal spread over the femoral artery within the subsartorial fat compartment resembling the injections within the canal but with ultrasonographic distinct features. These injections spread only half the length of the adductor canal. The only nerve observed within the adductor canal was the saphenous nerve.

CONCLUSIONS

Injection of 15 ml dye was sufficient to spread throughout the adductor canal and beyond both proximally and distally. Distinct ultrasonographic features could be identified separating a subsartorial injection from an injection within the adductor canal with consequent differences in the spread.