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

Continuous adductor canal block versus continuous femoral nerve block for postoperative pain in patients undergoing knee arthroplasty: An updated meta-analysis of randomized controlled trials

Continuous adductor canal block (CACB) is almost a pure sensory nerve block and can provide effective analgesia without blocking the motor branch of the femoral nerve. Thus, the objective of this study was to systematically evaluate the efficacy of CACB versus continuous femoral nerve block (CFNB) on analgesia and functional activities in patients undergoing knee arthroplasty. PubMed, Embase and the Cochrane Central Register of Controlled Trials (from inception to 3 October 2023) were searched for randomized controlled trials (RCTs) that compared CACB with CFNB in patients undergoing knee arthroplasty. Registration in the PROSPERO International prospective register of the meta-analysis was completed, prior to initiation of the study (registration number: CRD42022363756). Two independent reviewers selected the studies, extracted data and evaluated risk of bias by quality assessment. Revman 5.4 software was used for meta-analysis and the summary effect measure were calculated by mean differences and 95% confidence intervals. Eleven studies with a total of 748 patients were finally included. Pooled analysis suggested that both CACB and CFNB showed the same degree of pain relief at rest and at motion at 12 h, 24 h and 48 h in patients undergoing knee arthroplasty. Compared with CFNB, CACB preserved the quadriceps muscle strength better (P<0.05) and significantly shortened the discharge readiness time (P<0.05). In addition, there was no significant difference in opioid consumption, knee extension and flexion, timed up and go (TUG) test, or risk of falls between the two groups. Thus, Compared with CFNB, CACB has similar effects on pain relief both at rest and at motion and opioid consumption for patients undergoing knee arthroplasty, while CACB is better than CFNB in preserving quadriceps muscle strength and shortening the discharge readiness time.

Addition of Surgeon-Administered Adductor Canal Infiltration to the Periarticular Infiltration in Total Knee Arthroplasty: Effect on Pain and Early Outcomes

BACKGROUND

Our aim was to study the additive effect of surgeon-administered adductor canal infiltration (SACI) over routine periarticular infiltration (PAI) on pain control [morphine consumption and pain score by the visual analog scale (VAS)] and early function [flexion and Timed Up and Go (TUG) test] post-total knee arthroplasty (TKA).

METHODS

We prospectively randomized 60 patients into 2 groups. Group I patients received the standard PAI, whereas in Group II, the patients received a SACI in addition to the PAI. The total volume of the injected drug and the postoperative pain management protocol were the same for all. The number of doses of patient-controlled analgesia (PCA) used for breakthrough pain was recorded as PCA consumption. For early function, flexion and the TUG test were used. The VAS score and PCA consumption were compared between the 2 groups by using analyses of variance with post hoc tests as indicated. The TUG test and flexion were compared using Student t tests. The level of significance was set at 0.05.

RESULTS

The PCA consumption in the first 6 hours was significantly higher in Group I (P = .04). The VAS at 6 hours was significantly lower in Group II (P = .042). The TUG test was comparable between the 2 groups preoperatively (P = .72) at 24 hours (P = .60) and 48 hours (P = .60) post-TKA. The flexion was comparable between the 2 groups preoperatively (P = .85) at 24 hours (P = .48) and 48 hours (P = .79) post-TKA.

CONCLUSIONS

Adding a SACI to PAI provides improved pain relief and reduces opioid consumption without affecting early function post-TKA. A SACI avoids the need for an anesthesiologist or specialized equipment with no added operating time and minimal added cost. We recommend routine use of SACI for all patients undergoing TKA.

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

BACKGROUND

The analgesic effectiveness of contemporary motor-sparing nerve blocks used in combination for analgesia in total knee arthroplasty is unclear. This network meta-analysis was conducted to evaluate the analgesic effectiveness of adding single-injection or continuous adductor canal block (ACB) with or without infiltration of the interspace between the popliteal artery and the capsule of the posterior knee (iPACK) to intraoperative local infiltration analgesia (LIA), compared to LIA alone, after total knee arthroplasty.

METHODS

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

RESULTS

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

CONCLUSIONS

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

EDITOR’S PERSPECTIVE

Predictive Ability of Perfusion Index for Determining the Success of Adductor Canal Nerve Block for Postoperative Analgesia in Patients Undergoing Unilateral Total Knee Arthroplasty

BACKGROUND

The perfusion index (PI) is an objective method used to determine a successful nerve block. This study aimed to investigate the prognostic ability of the PI for a successful adductor canal nerve block (ACB) and suggest the optimal PI cut-off value for predicting a block.

METHODS

This study was a prospective observational study and enrolled a total of 39 patients. The patients were dichotomized into successful and inappropriate ACB groups according to the results of the sensation tests. The PI value, Pleth variability index (PVi) value, and heart rate were recorded one minute before the block, at the time of the block, and one to 30 min after the block at one-minute intervals. Delta (dPI), which was defined as the difference in PI value from the baseline (the value one minute before the block), was the primary outcome. The area under the receiver operating characteristic curve (AUROC) was calculated to determine the dPI prognostic accuracy and optimal cut-off value.

RESULTS

Successful ACB was achieved in 33 patients, while ACB was inappropriate in six patients. The dPI showed significant differences between the two groups under the time interval measured (p = 0.001). The dPI at 5 and 20 min showed good prognostic ability for a successful block, with optimal cut-off values of 0.33 (AUROC: 0.725, 95% CI 0.499-0.951) and 0.64 (AUROC: 0.813, 95% CI 0.599-1.000), respectively.

CONCLUSIONS

The dPI is an effective predictor of successful ACB. The suggested dPI cut-off values at 5 and 20 min were below 0.33 and 0.64, respectively.

Total joint replacement in ambulatory surgery

Total joint arthroplasty is one of the most commonly performed surgical procedures in the United States, and projected numbers are expected to double in the next ten years. From 2018 to 2020, total hip and knee arthroplasty were removed from the United States' Center for Medicare and Medicaid Services "inpatient-only" list, accelerating this migration to the ambulatory setting. Appropriate patient selection, including age, body mass index, comorbidities, and adequate social support, is critical for successful ambulatory total joint arthroplasty. General anesthesia and neuraxial anesthesia are both safe and effective anesthetic choices, and recent studies in this population have found no difference in outcomes. Multimodal analgesia, including acetaminophen, nonsteroidal anti-inflammatory drugs, local infiltration analgesia, and peripheral nerve blocks, is the foundation for adequate pain control. Common reasons for "failure to launch" include postoperative urinary retention, postoperative nausea and vomiting, inadequate analgesia, and hypotension.

Early versus delayed postoperative adductor canal block in total knee arthroplasty

Background

We hypothesized that patients who received an adductor canal block (ACB) in the operating room following unilateral total knee arthroplasty would have a lower oral morphine milligram equivalent (MME) consumption during the postanesthesia care unit (PACU) phase 1 recovery period compared to patients who received an ACB in the PACU.

Methods

This was a retrospective cohort study of patients who underwent robotic-assisted unilateral total knee arthroplasty under general anesthesia between March 1, 2020, and February 28, 2021, and received postoperative ACB either in the operating room or the PACU.

Results

A total of 36 and 178 patients received postoperative ACB in the operating room and PACU, respectively, and had median and interquartile range MME consumption in the PACU of 22.5 (20-40) mg and 30.0 (20-40) mg (P = 0.76), respectively. Patients who had an ACB performed in the operating room and PACU had median and interquartile ranges of time spent in the PACU of 101 (75-178) minutes and 186 (125-272) minutes (P < 0.01), respectively.

Conclusion

Patients who received an ACB in the operating room did not have a lower OME consumption than patients who received an ACB in the PACU but did have a shorter PACU length of stay.

Effects of a Continuous Adductor Canal Block After Total Knee Arthroplasty

This retrospective cohort study analyzed the short-term outcomes of patients undergoing total knee arthroplasty receiving periarticular anesthetic injections (PAIs) with and without continuous adductor canal blocks (CACBs) regarding early postoperative narcotic use, pain scores, and range of motion with otherwise similar postoperative regimens. Two hundred ninety-four patients were included: 120 received PAIs with CACBs, and 174 received PAIs only. Matched analysis was performed for type of anesthesia. There were substantial decreases in early inpatient narcotic use with the addition of CACBs to PAIs with general and spinal anesthesia without an adverse effect on pain, knee range of motion, or length of stay. [Orthopedics. 2023;46(3):185-191.].

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Adductor Canal Blocks Are Not Associated With Improved Early Postoperative Outcomes in Patients Undergoing Total Knee Arthroplasty

Background: As length of stay after total knee arthroplasty (TKA) continues to shorten, interventions that may reduce early postoperative pain and complications must be studied. Peripheral nerve block is being explored as a potential means of improving pain management. The purpose of this study was to evaluate the impact of adductor canal block (ACB) on postoperative outcomes for patients undergoing TKA. Methods: We conducted a retrospective review of 565 patients who received unilateral TKA under spinal anesthesia with a periarticular anesthetic injection. Patients were divided by ACB status. Univariate comparisons and multivariate regression were used to compare outcomes for patients receiving ACBs vs those who did not. Results: Of the 565 patients, 167 received an ACB, and 398 did not. Patients who received an ACB were less likely to require nausea medication during the immediate postoperative period. Length of stay, narcotic consumption, rate of discharge to home, postanesthesia care unit recovery time, urinary retention, ability to complete physical therapy, and 30-day readmission rate did not differ significantly between groups. After risk adjustment, the only significant finding was decreased likelihood of nausea in patients receiving an ACB. Conclusion: ACBs appear to have little to no significant impact on early clinical outcomes in patients having TKA under spinal anesthesia with a periarticular anesthetic injection. Further study of larger patient cohorts is required to validate these findings.

Efficacy and Side Effect Profile of Intrathecal Morphine versus Distal Femoral Triangle Nerve Block for Analgesia following Total Knee Arthroplasty: A Randomized Trial

(1) Background: The management of postoperative pain after knee replacement is an important clinical problem. The best results in the treatment of postoperative pain are obtained using multimodal therapy principles. Intrathecal morphine (ITM) and single-shot femoral nerve block (SSFNB) are practiced in the treatment of postoperative pain after knee replacement, with the most optimal methods still under debate. The aim of this study was to compare the analgesic efficacy with special consideration of selected side effects of both methods. (2) Materials and methods: Fifty-two consecutive patients undergoing knee arthroplasty surgery at the Department of Orthopedics and Traumatology of the Medical University of Warsaw were included in the study. Patients were randomly allocated to one of two groups. In the ITM group, 100 micrograms of intrathecal morphine were used, and in the SSFNB group, a femoral nerve block in the distal femoral triangle was used as postoperative analgesia. The other elements of anesthesia and surgery did not differ between the groups. (3) Results: The total dose of morphine administered in the postoperative period and the effectiveness of pain management did not differ significantly between the groups (cumulative median morphine dose in 24 h in the ITM group 31 mg vs. SSFNB group 29 mg). The incidence of nausea and pruritus in the postoperative period differed significantly in favor of patients treated with a femoral nerve block. (4) Conclusions: Although intrathecal administration of morphine is similarly effective in the treatment of pain after knee replacement surgery as a single femoral triangle nerve block, it is associated with a higher incidence of cumbersome side effects, primarily nausea and pruritus.

The Ramifications of Opioid Utilization and Outcomes of Alternative Pain Control Strategies for Total Knee Arthroplasties

Morbidity and mortality related to opioid use has generated a public health crisis in the United States. Total knee arthroplasty (TKA) is an increasingly common procedure and is often accompanied by post-operative opioid utilization. Unfortunately, post-operative opioid usage after TKA has been shown to lead to higher rates of complications, longer hospital stays, increased costs, and more frequent need for revision surgery. Pre-operative opioid utilization has been shown to be one of the most important predictors of post-operative opioid usage. Additional risk factors for continued post-operative opioid utilization after TKA include pre-operative substance and tobacco use as well as higher post-operative prescription dosages, younger age, female gender, and Medicaid insurance. One method for mitigating excessive post-operative opioid utilization are Enhanced Recovery After Surgery (ERAS) protocols, which include a multidisciplinary approach that focuses on perioperative factors to optimize patient recovery and function after surgery. Additional strategies include multimodal pain regimens with epidural anesthetics, extended duration local anesthetics and adjuvants, and ultrasound guided peripheral nerve blocks. In recent years, opioid prescribing duration limitations have also been put into place by state and federal government, hospital systems, and ambulatory surgery centers making effective acute pain management imperative for all stakeholders. In this regard, as rates of TKA continue to increase across the United States, multidisciplinary efforts by all stakeholders are needed to ensure adequate pain control while preventing the negative sequalae of opioid medications.

Adductor canal block versus femoral nerve block for pain control after total knee arthroplasty: A systematic review and Meta-analysis

BACKGROUND

Femoral nerve block is a widely accepted nerve block method with evident reduction in consumption of opioid painkiller and minimization of the duration of hospital stay but may cause weakness of quadriceps muscle strength. Adductor canal block is another nerve block technique that attracts the attention of scientific community nowadays because of its possible superiority over Femoral nerve block regarding mobility and muscle strength.

METHODS

This is a systematic review and meta-analysis of 33 studies, aiming to compare femoral nerve block with adductor canal block following total knee arthroplasty regarding pain control and mobilization.

RESULTS

Adductor canal block showed better preservation of quadriceps muscle strength (MD = 0.28, 95% CI [0.11, 0.46], P = .002), and better mobilization up to 2 days postoperatively. However, no significant difference was found between the 2 interventions regarding pain control (MD = 0.06, 95% CI [-0.06, 0.17], P = .33) or opioid consumption (SMD = 0.08, 95% CI [-0.06, 0.22], P = .28) up to 2 days postoperatively. The better mobilization results of adductor canal block did not translate into a significant difference in the risk of falls or patients' satisfaction; however, adductor canal block patients had less mean length of hospital stay than the patients with femoral nerve block.

CONCLUSION

Both femoral nerve block and adductor canal block provide similar results regarding pain control and opioid consumption, however adductor canal block provides better preservation of quadriceps strength and mobilization, giving it more advantage over femoral nerve block.

Review on Nerve Blocks Utilized for Perioperative Total Knee Arthroplasty Analgesia

Total Knee Arthroplasty (TKA) is an increasingly common procedure performed for advanced osteoarthritis. Optimal perioperative pain management strategies are critical for early mobilization and shorter hospital stays in TKA. Peripheral nerve blocks commonly used in TKA perioperative analgesia including individual and combined femoral, obturator, sciatic, lumbar plexus, and adductor canal nerve blocks. Overall, the safety profile varies depending on which block is utilized, but the current evidence suggests when optimally chosen and delivered, peripheral nerve blocks may provide a safe, effective option for perioperative analgesia. Determining optimal analgesic regimens for total knee arthroplasty is critical to improve postoperative pain, patient satisfaction, decreasing opioid usage, recovery times and functional outcomes, and as such, peripheral nerve blocks may represent a viable option to supplement analgesic requirements in the perioperative period.

Decrease in Residual Neurological Symptoms After Institutional Changes in Peripheral Nerve Block Use for Pediatric Knee Surgery

BACKGROUND

Peripheral nerve blocks (PNBs) have recently been associated with a higher incidence of complications than previously thought. We compared: (1) incidence of PNB-related residual neurological symptoms and (2) patient selection, operative practices, and anesthesia practices for pediatric knee surgery patients before and after changes in PNB administration at our institution.

METHODS

We compared data from pediatric patients who underwent knee surgery with PNBs from 2014 to 2016 (cohort 1; 100 patients) or 2017 to 2019 (cohort 2; 104 patients). Cohort 2 was treated after PNB administration was limited to a dedicated anesthesia block team at our institution. We used t tests and χ2 tests, with an α level of 0.05.

RESULTS

The incidence of PNB-related neurological complications was lower in cohort 2 (0.96%;) than cohort 1 (6%) (P=0.045). The 1 complication in cohort 2 was numbness proximal to the knee. Cohort 1 had 5 cases of numbness proximal to the knee and 1 case of neuropathic pain upon palpation of the PNB site. The proportion of female patients was greater in cohort 2 (57%) than cohort 1 (36%) (P=0.01); age and body mass index did not differ between cohorts. In cohort 2, the mean operating time was longer, and tourniquets were used more frequently (both, P<0.01). A greater proportion of PNBs were performed by fellows in cohort 2 (67%) versus cohort 1 (55%) (P=0.01). A smaller proportion of PNBs were performed by residents in cohort 2 (6.9%) versus cohort 1 (16%) (P=0.01). The most common anatomic site for PNBs was the femoral nerve (51%) in cohort 1 and the saphenous nerve (51%) in cohort 2 (P<0.01).

CONCLUSIONS

The incidence of PNB-related complications after pediatric knee surgery decreased significantly after institutional changes in the regulation of PNB use. This decrease may be explained by shifts toward more experienced providers administering PNBs and preference for more distal anatomic sites, suggesting ways other institutions may lower their PNB complication rates.

LEVEL OF EVIDENCE

Level III-retrospective prognostic study.

An Update on Multimodal Pain Management After Total Joint Arthroplasty

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Multimodal analgesia has become the standard of care for total joint arthroplasty as it provides superior analgesia with fewer side effects than opioid-only protocols.

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Systemic medications, including nonsteroidal anti-inflammatory drugs, acetaminophen, corticosteroids, and gabapentinoids, and local anesthetics via local infiltration analgesia and peripheral nerve blocks, are the foundation of multimodal analgesia in total joint arthroplasty.

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Ideally, multimodal analgesia should begin preoperatively and continue throughout the perioperative period and beyond discharge.

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There is insufficient evidence to support the routine use of intravenous acetaminophen or liposomal bupivacaine as part of multimodal analgesia protocols.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Trends in Pediatric Pain: Thinking Beyond Opioids

Trends in pediatric pain management are moving toward thinking beyond opioids. Regional anesthetic techniques, such as quadratus lumborum and erector spinae plane blocks, demonstrate efficacy and safety in pediatric populations. Extremity blocks with motor-sparing characteristics also are used. Adjuvants may be added to pediatric peripheral nerve blocks to increase duration of action and improve block efficacy. For medical management, pediatric pain management frequently uses nonopioid medications. These opioid-sparing medications and regional techniques are used to facilitate enhanced recovery after surgery in pediatric surgical patients. Virtual reality is a field where technology can aid in managing acute pain in pediatric patients.

Postoperative Pain Management in Total Knee Arthroplasty

Total knee arthroplasty (TKA) is one of the most common surgeries performed to relieve joint pain in patients with end‐stage osteoarthritis or rheumatic arthritis of the knee. However, TKA is followed by moderate to severe postoperative pain that affects postoperative rehabilitation, patient satisfaction, and overall outcomes. Historically, opioids have been widely used for perioperative pain management of TKA. However, opioids are associated with undesirable adverse effects, such as nausea, respiratory depression, and retention of urine, which limit their application in daily clinical practice. The aim of this review was to discuss the current postoperative pain management regimens for TKA. Our review of the literature demonstrated that multimodal analgesia is considered the optimal regimen for perioperative pain management of TKA and improves clinical outcomes and patient satisfaction, through a combination of several types of medications and delivery routes, including preemptive analgesia, neuraxial anesthesia, peripheral nerve blockade, patient‐controlled analgesia and local infiltration analgesia, and oral opioid/nonopioid medications. Multimodal analgesia provides superior pain relief, promotes recovery of the knee, and reduces opioid consumption and related adverse effects in patients undergoing TKA.

Regional Catheters for Postoperative Pain Control: Review and Observational Data

Context

Perioperative analgesia is an essential but frequently underrated component of medical care. The purpose of this work is to describe the actual situation of surgical patients focusing on effective pain control by discarding prejudice against ‘aggressive’ measures.

Evidence Acquisition

This is a narrative review about continuous regional pain therapy with catheters in the postoperative period. Included are the most-relevant literature as well as own experiences.

Results

As evidenced by an abundance of studies, continuous regional/neuraxial blocks are the most effective approach for relief of severe postoperative pain. Catheters have to be placed in adequate anatomical positions and meticulously maintained as long as they remain in situ. Peripheral catheters in interscalene, femoral, and sciatic positions are effective in patients with surgery of upper and lower limbs. Epidural catheters are effective in abdominal and thoracic surgery, birth pain, and artery occlusive disease, whereas paravertebral analgesia may be beneficial in patients with unilateral approach of the truncus. However, failure rates are high, especially for epidural catheter analgesia. Unfortunately, many reports lack a comprehensive description of catheter application, management, failure rates and complications and thus cannot be compared with each other.

Conclusions

Effective control of postoperative pain is possible by the application of regional/neuraxial catheters, measures requiring dedication, skill, effort, and funds. Standard operating procedures contribute to minimizing complications and adverse side effects. Nevertheless, these methods are still not widely accepted by therapists, although more than 50% of postoperative patients suffer from ‘moderate, severe or worst’ pain.

Adductor canal block: Effect of volume of injectate on sciatic extension

Context:

Spread of local anesthetic within adductor canal to peroneal and tibial nerves is described in literature. This spread could be volume-dependent.

Aims:

In this study, we compared the diffusion of two volumes of 0.375% ropivacaine to popliteal fossa.

Settings and Design:

This was a prospective, randomized controlled, single-blind study conducted in Kassab Orthopaedic Institute of Tunis for 1 year (2018).

Materials and Methods:

A total of 42 patients, American Society of Anesthesiologists I/II scheduled for knee arthroscopy under spinal anesthesia scheduled to receive adductor canal block, were randomized into two groups: group N received 20 mL of ropivacaine 0.375% and group H received 40 mL. We evaluated sensory motor blocks of both peroneal and tibial nerves at 30 and 60 min.

Statistical Analysis Used:

Chi-square or Fisher's exact test was used to compare the number and percentage. P <0.05 was significant.

Results:

At 60 min, complete sensory block of the peroneal nerve was obtained for 16 patients in group H versus 15 patients in group N with no statistically significant difference (P = 0.60). The difference was also not significant (P = 0.27) for the tibial nerve: 14 patients for group H versus 16 for group N. Motor blockade was rare in the two nerve territories.

Conclusion:

Spread of 0.375% ropivacaine to popliteal fossa resulted in high rate of complete sensory blockade of both peroneal and tibial nerves. Diffusion of local anesthetic was not volume-dependent.