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

Adductor Canal Block Versus Femoral Nerve Block for Postoperative Pain Management in Anterior Cruciate Ligament Reconstruction: A Prospective Interventional Study

Background A common knee joint disorder is injury to the anterior cruciate ligament (ACL), which often requires surgery. Proper pain control after the surgery facilitates fast recovery and prevents chronic pain. To provide analgesia for knee procedures, the use of opioids, non-steroidal anti-inflammatory medications, and regional techniques are commonly employed. This study aims to evaluate the efficacy of adductor canal block (ACB) and femoral nerve block (FNB) for postoperative pain management after anterior cruciate ligament reconstructions (ACLRs). Methodology This prospective interventional study included 30 participants scheduled for patellar graft ACLR. They were assigned into groups, i.e., ACB and FNB, with 15 patients each. The evaluation occurred one day before the operation, and all surgical procedures were performed using spinal anesthesia. During the postoperative period, a 10-point visual analog scale (VAS) was utilized to quantify pain intensity at the end of the surgery and at various intervals after the surgery. Patients with a VAS score greater than 4 received either FNB or ACB using bupivacaine 0.125%. Duration of analgesia time, power of quadriceps muscle, and neurologic complications were documented. Results No statistically significant value was observed in the mean duration of analgesia between the patients in ACB (348.33 minutes) and the patients in FNB (363.06 minutes). No motor block was observed in 12 patients who received ACB, while only four patients had a motor-sparing effect among those who received FNB. No neurological adverse effects were observed in the study participants. Conclusions ACB provides an equal duration of analgesia similar to FNB, and ACB significantly spares motor strength and maintains higher quadriceps power than FNB.

The Effectiveness of Adductor Canal Block Compared to Femoral Nerve Block on Readiness for Discharge in Patients Undergoing Outpatient Anterior Cruciate Ligament Reconstruction: A Multi-Center Randomized Clinical Trial

This study evaluated the effect of adductor canal block (ACB) versus femoral nerve block (FNB) on readiness for discharge in patients undergoing outpatient anterior cruciate ligament (ACL) reconstruction. We hypothesized that ACB would provide sufficient pain relief while maintaining motor strength and safety, thus allowing for earlier discharge. This was a randomized, multi-center, superiority trial. From March 2014 to July 2017, patients undergoing ACL reconstruction were enrolled. The primary outcome was the difference in readiness for discharge, defined as Post-Anesthetic Discharge Scoring System score ≥ 9. Twenty-six patients were allocated to FNB and twenty-seven to ACB. No difference in readiness for discharge was found (FNB median 1.8 (95% CI 1.0 to 3.5) vs. ACB 2.9 (1.5 to 4.7) hours, p = 0.3). Motor blocks and (near) falls were more frequently reported in patients with FNB vs. ACB (20 (76.9%) vs. 1 (3.7%), p < 0.001, and 7 (29.2%) vs. 1 (4.0%), p = 0.023. However, less opioids were consumed in the post-anesthesia care unit for FNB (median 3 [0, 21] vs. 15 [12, 42.5] oral morphine milligram equivalents, p = 0.004) for ACB. Between patients with FNB or ACB, no difference concerning readiness for discharge was found. Despite a slight reduction in opioid consumption immediately after surgery, FNB demonstrates a less favorable safety profile compared to ACB, with more motor blocks and (near) falls.

Femoral Nerve Block and Local Instillation Analgesia Associated With More Reliable Efficacy in Regional Anesthesia Interventions Within 24 Hours Following Anterior Cruciate Ligament Reconstruction: A Network Meta-analysis

PURPOSE

To assess the relative effectiveness of different regional anesthetic techniques (peripheral nerve blocks, local instillation analgesia, including intra-articular, subcutaneous, and periarticular infiltration) in patients undergoing anterior cruciate ligament reconstruction (ACLR).

METHODS

PubMed, Embase, Cochrane Library, and Web of Science databases were searched from their inception to December 31, 2020. The search was supplemented by manual review of relevant reference lists. Randomized controlled trials of participants after ACLR that compared regional anesthesia interventions were selected. The 2 coprimary outcomes were (1) rest pain scores and (2) cumulative oral morphine equivalent consumption on day 1 (24 hours) post-ACLR. Data were pooled using a Bayesian framework.

RESULTS

Of 759 records identified, 46 trials were eligible, evaluating 9 interventions in 3,171 patients. Local instillation analgesia (LIA), including intra-articular, subcutaneous, and periarticular infiltration, had significant improvement in pain relief as compared with placebo (-0.91; 95% CrI -1.45 to -0.37). Femoral nerve block (FNB) also showed significant effects in relieving pain as compared with placebo (-0.70; 95% 95% credible interval [CrI] -1.28 to -0.12). Compared with placebo, a significant reduction in opioid consumption was found in LIA (mean difference -13.29 mg; 95% CrI -21.77 to -4.91) and FNB (mean difference -13.97 mg; 95% CrI -24.71 to -3.04). Femoral and sciatic nerve block showed the greatest ranking for pain relief and opioid consumption without significant evidence (P > .05) to support superiority in comparison with placebo, respectively.

CONCLUSIONS

Our meta-analysis shows that FNB and LIA can significantly diminish postoperative pain and reduce opioid consumption following ACLR compared with placebo in the setting of regional anesthesia, and femoral and sciatic nerve block may be the number 1 top-ranked analgesic technique despite high uncertainty.

LEVEL OF EVIDENCE

I, Systematic review of Level I studies.

Effect of Adductor Canal Block Combined with Local Infiltration Analgesia on Postoperative Pain of Knee Arthroscopy Under General Anesthesia: A Randomized Controlled Trial

INTRODUCTION

Postoperative pain in knee arthroscopy (KA) is a common and troublesome problem. The best local analgesic technique for relieving postoperative pain in patients with KA has not been well studied. This prospective trial aimed to observe whether adductor canal block (ACB) combined with local infiltration analgesia (LIA) could further decrease the incidence of postoperative pain undergoing KA.

METHODS

This randomized controlled study recruited 60 patients aged 18-65 years, ASA I-II, who received KA, and randomly divided them into ACB + LIA group and LIA group. The primary outcome was the incidence of postoperative pain 24 h after surgery. The secondary outcomes included the incidence of quadriceps femoris weakness, and the consumption of opioids during operation.

RESULTS

A total of 60 participants completed the trial. The incidence of postoperative pain 24 h after surgery in ACB + LIA group was lower than that in the LIA group (10% [3 of 30] vs. 33% [10 of 30]; P = 0.028). There was no difference in the incidence of quadriceps muscle weakness 24 h after surgery between the two groups. The consumption of remifentanil and sufentanil in ACB + LIA group was significantly lower than that in LIA group (P = 0.006, P < 0.001).

CONCLUSIONS

Compared with patients receiving LIA alone, ACB combined with LIA could reduce the incidence of postoperative pain while retaining the strength of the quadriceps femoris in patients undergoing KA and reduce the consumption of opioids during surgery.

CLINICAL TRIAL NUMBER AND REGISTRY URL

This study was registered at the Chinese Clinical Trial Registry with the registration number ChiCTR1800018463 on September 20, 2018. ( http://www.chictr.org.cn/showproj.aspx?proj=31192 ).

Network meta-analysis of the analgesic effectiveness of regional anaesthesia techniques for anterior cruciate ligament reconstruction

Anterior cruciate ligament reconstruction can cause moderate to severe acute postoperative pain. Despite advances in our understanding of knee innervation, consensus regarding the most effective regional anaesthesia techniques for this surgical population is lacking. This network meta-analysis compared effectiveness of regional anaesthesia techniques used to provide analgesia for anterior cruciate ligament reconstruction. Randomised trials examining regional anaesthesia techniques for analgesia following anterior cruciate ligament reconstruction were sought. The primary outcome was opioid consumption during the first 24 h postoperatively. Secondary outcomes were: rest pain at 0, 6, 12 and 24 h; area under the curve of pain over 24 h; and opioid-related adverse effects and functional recovery. Network meta-analysis was conducted using a frequentist approach. A total of 57 trials (4069 patients) investigating femoral nerve block, sciatic nerve block, adductor canal block, local anaesthetic infiltration, graft-donor site infiltration and systemic analgesia alone (control) were included. For opioid consumption, all regional anaesthesia techniques were superior to systemic analgesia alone, but differences between regional techniques were not significant. Single-injection femoral nerve block combined with sciatic nerve block had the highest p value probability for reducing postoperative opioid consumption and area under the curve for pain severity over 24 h (78% and 90%, respectively). Continuous femoral nerve block had the highest probability (87%) of reducing opioid-related adverse effects, while local infiltration analgesia had the highest probability (88%) of optimising functional recovery. In contrast, systemic analgesia, local infiltration analgesia and adductor canal block were each poor performers across all analgesic outcomes. Regional anaesthesia techniques that target both the femoral and sciatic nerve distributions, namely a combination of single-injection nerve blocks, provide the most consistent analgesic benefits for anterior cruciate ligament reconstruction compared with all other techniques but will most likely impair postoperative function. Importantly, adductor canal block, local infiltration analgesia and systemic analgesia alone each perform poorly for acute pain management following anterior cruciate ligament reconstruction.

A Practical Guide to Lower Extremity Nerve Blocks for the Sports Medicine Surgeon

BACKGROUND

Peripheral nerve blocks (PNBs) are vital in the administration of surgical analgesia and have grown in popularity for use in lower extremity arthroscopic procedures because of their capacity to safely and effectively control pain. The number and specificity of PNBs, however, have made choosing the best option for a procedure nebulous for orthopaedic surgeons.

PURPOSE

To present a narrative literature review of the PNBs available for arthroscopic hip and knee procedures that is adapted to an audience of orthopaedic surgeons.

STUDY DESIGN

Narrative literature review.

METHODS

A combination of the names of various lower extremity PNBs AND "hip arthroscopy" OR "knee arthroscopy" was used to search the English medical literature including PubMed, Cochrane Library, ScienceDirect, Embase, and Scopus. Placement technique, specificity of blockade, efficacy, and complications were assessed. Searches were performed through May 2, 2021.

RESULTS

A total of 157 studies were included in this review of lower extremity PNBs. Femoral nerve, lumbar plexus, sciatic nerve, and fascia iliaca compartment blocks were most commonly used in arthroscopic hip surgery, while femoral nerve, 3-in-1, and adductor canal blocks were preferred for arthroscopic knee surgery. Each block demonstrated a significant benefit (P > .05) in ≥1 of the following outcomes: intraoperative morphine, pain scores, nausea, and/or opioid consumption. Combination blocks including the lateral femoral cutaneous nerve block, obturator nerve block, quadratus lumborum block, and L1 and L2 paravertebral block have also been described. Complication rates ranged from 0% to 4.8% in those administered with ultrasound guidance. The most commonly reported complications included muscular weakness, postoperative falls, neuropathy, intravascular and intraneural injections, and hematomas.

CONCLUSION

When administered properly, PNBs were a safe and effective adjuvant method of pain control with a significant potential to limit postoperative narcotic use. While blockade choice varies by surgeon preference and procedure, all PNBs should be administered with ultrasound guidance, and vigilant protocols for the risk of postoperative falls should be exercised in patients who receive them.

Comparison of adductor canal block and femoral nerve block for pain management in anterior cruciate ligament reconstruction: A meta-analysis of randomized controlled trials

OBJECTIVE

To compare the efficacy of adductor canal block and femoral nerve block for pain management in patients with anterior cruciate ligament reconstruction.

METHODS

A computerized search was performed in the database of PubMed, Embase, Web of Science and Cochrane Library for randomized controlled trials. The outcome measures included visual analog scale, morphine consumption, quadriceps strength, length of hospitalization and postoperative adverse events. The risk of bias of randomized controlled trials was assessed according to the Cochrane Risk of Bias Tool. All quantitative syntheses were completed using STATA version 14.

RESULTS

Seven randomized controlled trials involving a total of 643 patients were included in our meta-analysis. The present meta-analysis indicated that there were no significant differences between the 2 groups in terms of postoperative pain score, opioid consumption, length of hospitalization or adverse effects after anterior cruciate ligament reconstruction. However, adductor canal block showed superior quadriceps strength and range of motion in the early postoperative period.

CONCLUSION

Adductor canal block shows similar and adequate analgesia compared to the femoral nerve block in anterior cruciate ligament reconstruction and adductor canal block can preserve a higher quadriceps strength and better range of motion.

Comparative Study of Adductor Canal Block and Femoral Nerve Block for Postoperative Analgesia After Arthroscopic Anterior Cruciate Ligament Tear Repair Surgeries

Objective: The study aimed to compare an adductor canal block (ACB) with a femoral nerve block (FNB) with regard to their analgesic efficacy and the quadriceps muscle strength in patients following arthroscopic anterior cruciate ligament (ACL) tear repair surgeries.

Materials and Methods: Ninety patients in the American Society of Anaesthesiologists (ASA) status I or II undergoing arthroscopic ACL tear repair surgeries under subarachnoid block were divided into three groups to receive ACB (Group ACB), FNB (Group FNB), and control (Group C). Each patient was assessed for Visual Analogue Scale (VAS) score, tramadol consumption, and quadriceps muscle strength postoperatively in the post anaesthesia care unit (PACU).

Results: There was no significant difference between the Group ACB and Group FNB regarding postoperative analgesia and total rescue analgesic consumption at 24 hrs postoperative. The mean VAS score at two, four, and six hours and total rescue analgesic consumption in 24 hrs were higher in the control group, which was statistically significant (p-value <0.05). Quadriceps muscle strength by straight leg raise test was significantly higher in the Group ACB compared with the Group FNB at 0, 6, 12, 18 hours postoperatively (p-value <0.0001), whereas the difference between both study groups become statistically insignificant at 24 hours postoperative.

Conclusion: ACB preserved quadriceps muscle strength better than FNB, without a significant difference in postoperative analgesia after arthroscopic ACL tear repair surgeries.

Most Analgesia Treatments Have No Clinical Significance for Anterior Cruciate Ligament Reconstruction: A Network Meta-analysis of 66 Randomized Controlled Trials

PURPOSE

To assess the relative efficacy of several clinical treatments for postoperative analgesia of anterior cruciate ligament reconstruction through network meta-analysis based on multiple published randomized controlled trials.

METHODS

We searched PubMed, the Cochrane library, EMBASE, and Web of Science, each from inception until February 15, 2021. Outcomes including pain scores at rest (visual analog scale, numerical rating scales, and other scales, which were converted to a standardized 0-10 scale), morphine consumption, and complications were meta-analyzed. Quality of the included studies was assessed using the Cochrane risk-of-bias tool. The authors defined the best choice for postoperative analgesia as the one that had significant difference in pain scores, morphine consumption, and had no significant difference in the risk of complications compared with placebo in the initial 48 postoperative hours.

RESULTS

In total, 66 studies with 4,168 patients were included in this network meta-analysis. Only periarticular infiltration was significantly superior to placebo in pain scores and morphine consumption (pain at 2 hours: mean difference [MD] -0.74, 95% confidence interval [CI] -1.36 to -0.12; pain at 6 hours: MD -0.81, 95% CI -1.42 to -0.21; pain at 12 hours: MD -0.85, 95% CI -1.53 to -0.17; pain at 24 hours: MD -0.80, 95% CI -1.19 to -0.40; morphine consumption at 24 hours: MD -10.12, 95% CI -14.31 to -5.93; morphine consumption at 48 hours: MD -5.62, 95% CI -6.74 to -4.51). Periarticular infiltration did not increase the risk of complications compared with placebo (nausea and vomiting: odds ratio [OR] 0.63, 95% CI 0.34-1.16; pruritus: OR 0.74, 95% CI 0.35-1.58; urinary retention: OR 0.55, 95% CI 0.25-1.23). In addition, There was no significant difference between adductor canal block and femoral nerve block in pain scores and morphine consumption (pain at 2 hours: MD -0.01, 95% CI -1.44 to 1.42; pain at 6 hours: MD 0.29, 95% CI -0.28 to 0.86; pain at 12 hours: MD 0.36, 95% CI -0.44 to 1.16; pain at 24 hours: MD 0.26, 95% CI -0.22 to 0.75; pain at 48 hours: MD -0.36, 95% CI -0.97 to 0.24; morphine at 24 hours: MD 1.04, 95% CI -4.70 to 6.79; morphine at 48 hours: MD -0.32, 95% CI -0.70 to 0.07; postoperative nausea and vomiting: OR 1.07, 95% CI 0.55-2.09; pruritus: OR 1.36, 95% CI 0.66-2.79; urinary retention: OR 1.41, 95% CI 0.37-5.29).

CONCLUSIONS

Based on current evidence, most analgesic methods could result in lower pain scores and decrease morphine consumption when compared with placebo; however, differences between methods were small and inconsistent. There seemed to be no significant difference between adductor canal block and femoral nerve block in pain score, morphine consumption and complications.

LEVEL OF EVIDENCE

Level I, meta-analysis of Level I RCTs.

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

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

Analgesic Impact of a Popliteal Plexus Block to Standard Adductor Canal Block in Arthroscopic Anterior Cruciate Ligament Reconstruction: A Randomized Blind Clinical Trial

Background

Damage to the anterior cruciate ligament (ACL) is crippling and often requires an arthroscopic outpatient surgery. Nevertheless, many patients experience severe pain during the first day after ACL reconstruction (ACLR). The adductor canal block (ACB) has yielded conflicting results for post-ACLR pain relief. This research investigated the effect of a supplemental popliteal plexus block on postoperative pain outcomes compared to a sole ACB.

Methods

Following a randomized design, 60 cases scheduled for knee arthroscopy with ACLR using an ipsilateral hamstring graft were separated into two categories. Subjects in group A (n = 30) received an ACB only, while subjects in group B (n = 30) received combined ACB and popliteal plexus block (PPB).

Results

We found significant differences between the two groups. The time of the first analgesic request (TFR) was later for the combined ACB and PPB (median 8 h) compared to the ACB only group (median 0.5 h). Morphine consumption was lower for patients who received combined ACB and PPB (median 12 mg) compared to ACB only (median 30 mg). The number of the requested doses was lower for the combined ACB and PPB group (median 3 doses) compared to the ACB only group (median 7 doses).

Conclusions

The addition of PPB to ACB was associated with improved analgesia and a reduced need for opioid-based sedatives following ACLR with an ipsilateral hamstring graft (https://clinicaltrials.gov/ct2/show/NCT04020133).

Femoral nerve versus adductor canal block for early postoperative pain control and knee function after anterior cruciate ligament reconstruction with hamstring autografts: a prospective single-blind randomised controlled trial

INTRODUCTION

The optimal pain management strategy for postoperative pain after anterior cruciate ligament reconstruction (ACLR) remains unclear. This study compared femoral nerve block (FNB) and adductor canal block (ACB) for pain management of early postoperative pain, knee function, and recovery of activity of daily living (ADL) after ACLR using hamstring autografts.

MATERIAL AND METHODS

In this prospective, single-blind, randomised controlled trial, 64 patients aged 12-56 years who underwent anatomical double-bundle ACLR with a hamstring autograft between August 2019 and May 2020 were randomised to undergo preoperative FNB (n = 32) or ACB (n = 32). The peripheral nerve block was performed by a single experienced anaesthesiologist under ultrasound guidance. The primary outcomes were postoperative pain as evaluated using the visual analogue scale (VAS) at 3, 6, 12, 24, and 48 h postoperatively and the need for pain relief. The secondary outcome was knee function, including the recovery of range of motion, contraction of the vastus medialis, and stable walking with a double-crutch (ADL), as evaluated by blinded physical therapists.

RESULTS

There were no significant differences in patient demographics between the two groups. The VAS scores, need for pain relief, knee function, and ADL did not significantly differ between the groups.

CONCLUSION

FNB and ACB provided comparable outcomes related to early postoperative pain, knee function, and ADL after double-bundle ACLR using hamstring autografts. Further research is necessary to evaluate the mid- to long-term effect of each block on recovery of knee function and ADL.

LEVEL OF EVIDENCE

I.

Managing Perioperative Pain After Anterior Cruciate Ligament (ACL) Reconstruction: Perspectives from a Sports Medicine Surgeon

Anterior cruciate ligament reconstructions (ACLR) are a relatively common procedure in orthopedic sports medicine with an estimated 130,000 arthroscopic operations performed annually. Most procedures are carried out on an outpatient basis, and though success rates of ACLR are as high as 95%, pain remains the most common postoperative complication delaying patient discharge, and thereby increasing the costs associated with patient care. Despite the success and relative frequency of ACLR surgery, optimal and widely accepted strategies and regimens for controlling perioperative pain are not well established. In recent years, the paradigm of pain control has shifted from exclusively utilizing opiates and opioid medications in the acute postoperative period to employing other agents and techniques including nerve blocks, intra-articular and periarticular injections of local anesthetic agents, NSAIDs, and less commonly, ketamine, tranexamic acid (TXA), sedatives, gabapentin, and corticosteroids. More often, these agents are now used in combination and in synergy with one another as part of a multimodal approach to pain management in ACLR, with the goal of reducing postoperative pain, opioid consumption, and the incidence of delayed hospital discharge. The purpose of this review is to consolidate current literature on various agents involved in the management of postoperative pain following ACLR, including the role of classically used opiate and opioid medications, as well as to describe other drugs currently utilized in practice either individually or in conjunction with other agents as part of a multimodal regimen in pain management in ACLR.

Quadriceps and Hamstring Strength in Adolescents 6 Months After ACL Reconstruction With Femoral Nerve Block, Adductor Canal Block, or No Nerve Block

Background:

Femoral nerve block (FNB) and adductor canal block (ACB) have been used increasingly for pain control during anterior cruciate ligament (ACL) reconstruction in adolescent patients. However, recent evidence suggests that the use of FNB may affect quadriceps strength recovery 6 months after surgery.

Purpose/Hypothesis:

To compare postoperative isokinetic strength in adolescents who received FNB, ACB, or no block for perioperative analgesia during ACL reconstruction. We anticipated lower postoperative quadriceps and hamstring isokinetic deficits in adolescents who received FNB as compared with ACB.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Patients were included in the study if they had undergone hamstring tendon autograft ACL reconstruction by a single surgeon from July 2008 to January 2018 and if they underwent isokinetic muscle testing at 4 to 8 months postoperatively. The participants were divided into 3 groups (no block, FNB, and ACB), and we compared the deficit in percentages between the affected and unaffected limbs as calculated from the isokinetic quadriceps and hamstring strength testing at 60 and 180 deg/s. Between-group analysis was performed using analysis of variance, with an alpha of .05.

Results:

A total of 98 participants were included in the analysis (31 no block, 36 FNB, and 31 ACB). The mean ± SD age of the patients was 15.26 ± 1.15, 15.50 ± 1.42, and 15.71 ± 1.44, for no block, FNB, and ACB, respectively. At 5.61 months postoperatively, there was no significant difference across the 3 groups in isokinetic quadriceps deficits (P ≥ .99), and the only significant difference in isokinetic hamstring deficit was observed for peak flexion at 180 deg/s, in which the ACB group had lower peak torque than the FNB group (–9.80% ± 3.48% vs 2.37% ± 3.23%; P = .035). The ratio of participants with a deficit exceeding 15% did not differ significantly among the 3 groups.

Conclusion:

Contrary to previous research, our findings indicate only minimal difference in quadriceps strength among the 3 types of perioperative analgesia in adolescents approximately 6 months after ACL reconstruction. The only significant strength deficit was seen in the hamstrings of patients receiving ACB at peak flexion as compared with those receiving FNB.

Analgesic effect of continuous adductor canal block versus continuous femoral nerve block for knee arthroscopic surgery: a randomized trial

Background and objectives

Anterior cruciate ligament reconstruction (ACLR) is one of the most frequently performed orthopedic procedures. The ability to perform ACLR on an outpatient basis is largely dependent on an effective analgesic regimen. The aim of the study was to compare the analgesic effect between continuous adductor canal block (cACB) and femoral nerve block (cFNB) during arthroscopy guided ACLR.

Method

In this prospective, randomized, controlled clinical trial, 60 ASA I/II patients for arthroscopic ACLR were recruited. Patients in Group I received cACB and those in Group II cFNB. A bolus dose of 20 cc 0.5% levobupivacaine followed by 0.125% 5 mL.h^-1 was started for 24 hours. Rescue analgesia in the form of paracetamol 1 g intravenous (IV) was given. Parameters assessed were time of first rescue analgesia, total analgesic requirement in 24 hours, and painless range of motion of the knee (15 degrees of flexion to further painless flexion).

Results

The time-to-first postoperative analgesic request (hours) was earlier in Group II (14.40 ± 4.32) than Group I (16.90 ± 3.37) and this difference was statistically significant (p < 0.05). The cumulative 24-h analgesic consumption (paracetamol in g) was 0.70 ± 0.47 in Group I and 1.70 ± 0.65 in Group II (p < 0.001). The painless range of motion (degree) was 55.67 ± 10.40 in Group I and 40.00 ± 11.37 in Group II (p < 0.001).

Conclusion

The findings of this study suggest that continuous adductor canal block provides superior analgesia in patients undergoing arthroscopic ACLR when compared to continuous femoral nerve block.

Pain Management Strategies After Anterior Cruciate Ligament Reconstruction: A Systematic Review With Network Meta-analysis

PURPOSE

To systematically review randomized controlled trials (RCTs) evaluating various pain control interventions after anterior cruciate ligament reconstruction (ACLR) to determine the best-available evidence in managing postoperative pain and to optimize patient outcomes.

METHODS

A systematic review of the literature was performed based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. A study was included if it was an RCT evaluating an intervention to reduce postoperative pain acutely after ACLR in one of the following areas: (1) nerve blocks, (2) nerve block adjuncts, (3) intra-articular injections, (4) oral medications, (5) intravenous medications, (6) tranexamic acid, and (7) compressive stockings and cryotherapy. Quantitative and qualitative statistics were carried out, and network meta-analysis was performed where applicable.

RESULTS

Overall, 74 RCTs were included. Across 34 studies, nerve blocks were found to significantly reduce postoperative pain and opioid use, but there was no significant difference among the various nerve blocks in the network meta-analysis. Intra-articular injections consisting of bupivacaine and an adjunct were found to reduce reported postoperative pain scores up to 12 hours after ACLR, with significantly lower postoperative opioid use.

CONCLUSIONS

Nerve blocks and regional anesthesia are the mainstay treatment of postoperative pain after ACLR, with the commonly used nerve blocks being equally efficacious. Intra-articular injections consisting of bupivacaine and an adjunct were found to reduce reported postoperative pain scores up to 12 hours after ACLR, with significantly lower postoperative opioid use. There was promising evidence for the use of some oral and intravenous medications, tranexamic acid, and nerve block adjuncts, as well as cryotherapy, to control pain and reduce postoperative opioid use.

LEVEL OF EVIDENCE

Level II, systematic review and meta-analysis of RCTs.

Anterior cruciate ligament reconstruction with the use of adductor canal block can achieve similar pain control as femoral nerve block

PURPOSE

Moderate-to-severe postoperative pain remains a challenge for both patients and surgeons after anterior cruciate ligament reconstruction (ACLR). The purpose of this study was to systematically review the current evidence in the literature to compare adductor canal block (ACB) with femoral nerve block (FNB) in the treatment of ACLR.

METHODS

A comprehensive search of the published literature in PubMed, Scopus, EMBASE, and Cochrane Library databases was performed. Only English randomized clinical trials (RCTs) were included in this study. The primary outcome was pain score. Secondary outcome measures included opioid consumption, postoperative adverse events, patient satisfaction, and quadriceps strength.

RESULTS

Eight RCTs with a total of 587 patients were included. No statistically significant difference was observed between the ACB and FNB groups in pain scores at 6 h, 12 h, 24 h, or 48 h; cumulative opioid consumption at 24 h or 48 h; patient satisfaction at 24 or 48 h; and postoperative adverse event. However, ACB showed superior quadriceps strength in the early postoperative period.

CONCLUSIONS

Both treatments provided similar overall pain relief after ACLR. The potential benefits of quadriceps preservation with ACB are worthy of future study. Therefore, ACB is recommended as an attractive alternative to FNB as the peripheral nerve block of choice for ACLR.

LEVEL OF EVIDENCE

Meta-analysis of Level 1 was performed in this study.

Femoral nerve block vs adductor canal block after anterior cruciate ligament reconstruction under general anesthesia: A prospective randomized trial protocol

BACKGROUND

Femoral nerve block (FNB) is considered the preferred analgesia after anterior cruciate ligament reconstruction (ACLR), but leads to weakness in the quadriceps muscles. Adductor canal block (ACB) is a new sensory block technique that effectively relieves postoperative pain while preserving quadriceps strength. The purpose of our study was to compare the efficacy of FNB vs ACB for pain control after ACLR.

METHODS

This prospective, randomized, double-blind, controlled, superiority clinical trial was approved by the institutional review board in our university hospital. We enrolled 120 patients set to undergo ACLR in this randomized therapeutic trial. Sixty patients received FNB and the other 60 received ACB for postoperative pain control. All ACB and FNB were performed using ultrasound-guided single-shot procedures. The primary outcomes included maximum voluntary isovolumetric contraction and postoperative pain score. Secondary outcomes included total opioid consumption, length of hospital stay, complication, and satisfaction score.

RESULTS

This clinical trial might provide some insights to estimate and compare the safety and efficacy of ACB vs FNB following ACLR.

TRIAL REGISTRATION

This study protocol was registered in Research Registry (researchregistry5569).

Effect of Adductor Canal Block Versus Femoral Nerve Block on Quadriceps Strength, Function, and Postoperative Pain After Anterior Cruciate Ligament Reconstruction: A Systematic Review of Level 1 Studies

BACKGROUND

Femoral nerve block (FNB) is a popular technique for reducing postoperative pain in patients with anterior cruciate ligament reconstruction (ACLR), but it is also linked to a number of adverse effects, such as quadriceps weakness, antalgic ambulation, and increased fall risk. Adductor canal block (ACB) has been offered as a motor nerve-sparing alternative to FNB.

PURPOSE

To evaluate available literature that compares the effects of ACB and FNB on functional outcomes after arthroscopic ACLR.

STUDY DESIGN

Systematic review.

METHODS

Following the 2009 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a search of PubMed (Ovid), CINAHL, Scopus, Cochrane, and Google Scholar databases was conducted. Search terms were designed to capture studies comparing the effects of ACB and FNB in patients undergoing arthroscopic ACLR. Data were evaluated regarding study and patient characteristics, functional measures, opioid consumption, pain scores, and complications.

RESULTS

Eight randomized controlled trials (N = 655 patients) comparing the efficacy of ACB versus FNB in arthroscopic ACLR were included. The heterogeneity of outcome measures precluded meta-analysis. Seven studies reported functional measures, which included isokinetic strength, straight-leg raise, and other various measures. Follow-up periods varied between 1 hour and 6 months. In 3 trials, ACB was found to preserve quadriceps strength as measured using straight-leg raise for the first 12 to 24 hours after surgery, while 3 other trials found no difference between the groups. No differences were reported in isokinetic strength at 6 months. In other functional measures, ACB either outperformed or was equivalent to FNB. The majority of studies reporting opioid consumption, pain scores, and complications found no differences between the blocks.

CONCLUSION

This systematic review suggests that when compared with FNB, ACB preserves quadriceps function in the early postoperative period after ACLR while providing a similar level of analgesia. Limitations of this study include the use of various functional measures and limited long-term follow-up. More research evaluating long-term functional outcomes with standardized measures is needed to draw adequate conclusions regarding the effects of ACB and FNB on function after ACLR.

Adductor Canal Versus Femoral Nerve Block after Anterior Cruciate Ligament Reconstruction: A Systematic Review of Level I Randomized Controlled Trials Comparing Early Postoperative Pain, Opioid Requirements, and Quadriceps Strength

PURPOSE

To systematically review the literature to compare the adductor canal block (ACB) with the femoral nerve block (FNB) following primary anterior cruciate ligament reconstruction (ACLR) in terms of early postoperative analgesic requirements and postoperative quadriceps strength.

METHODS

A systematic review was performed by searching PubMed, the Cochrane Library, and Embase up to August 2019 to identify randomized controlled trials that compared postoperative pain and functional outcomes in patients following primary ACLR with ACB versus FNB. The search phrase used was: adductor canal femoral nerve anterior cruciate ligament. Patients were evaluated based on analgesic consumption and quadriceps muscle strength. Study quality and risk of bias were evaluated with the Modified Coleman Methodology Score and Cochrane risk-of-bias tool respectively.

RESULTS

Five studies (all Level I evidence) were identified that met inclusion criteria, including 221 patients undergoing primary ACLR with ACB (mean age 26.8 years, 68.3% male) and 221 with FNB (mean age 28.2 years, 67.0% male). Statistical assessment for heterogeneity found for opioid consumption of ACB versus FNB groups was I² = 97% (P < .0001). There were no significant differences in analgesic consumption within the first 24 hours following surgery between groups except in 1 study, in which patients receiving ACB required significantly greater analgesics (P < .001). Three studies using 3 different techniques to measure strength found patients receiving ACB to have significantly greater quadriceps muscle function within 24 hours of surgery when compared with patients receiving FNB (P < .05).

CONCLUSIONS

In patients undergoing ACLR, the ACB may provide similar analgesic requirements, and the included studies suggest a potential advantage in preserving muscle strength at short-term (24-48 hours) follow-up when compared with FNB. However, the differences in muscle strength assessments between studies do not allow for strong conclusions.

LEVEL OF EVIDENCE

I, systematic review and meta-analysis of Level I studies.

Comparison of Continuous Adductor Canal and Femoral Nerve Blocks for Analgesia and Return of Quadriceps Function After Anterior Cruciate Ligament Reconstruction in Adolescent Patients

PURPOSE

To compare early pain relief and late quadriceps function after anterior cruciate ligament reconstruction (ACLR) with hamstring autograft in adolescent patients treated with either a continuous femoral nerve block (cFNB) or continuous adductor canal block (cACB).

METHODS

We retrospectively reviewed a consecutive series of adolescent patients who underwent ACLR and received either a cACB or cFNB for postoperative pain management. Over a 1-year period, all patients underwent ACLR with cFNBs. Over the subsequent 9 months, all patients underwent their ACLR with cACBs. Patient demographics, postoperative pain scores, opioid consumption, satisfaction and complications, and dates and results of quadriceps function derived at the Return to Sports evaluation were compared.

RESULTS

Ninety-one patients (53 cFNB, 38 cACB) were reviewed. There were no differences in the demographics of the 2 groups. There were no statistically significant differences between groups in variations in postoperative pain scores (P = .21), or satisfaction with the blocks (P = .93). Patients in the cFNB group consumed a greater number of opioid doses on postoperative day 3 (2.2 ± 2.1 doses cFNB, 1.1 ± 1.6 doses cACB, P = .03) and a greater number of opioid doses overall for postoperative days 1 to 3 (mean 6.8 ± 5.3 doses cFNB, 3.8 ± 2.1 doses cACB, P = .03). There was no difference in time to return of acceptable quadriceps strength and function when comparing the 2 groups (30.9 ± 7.7 weeks cFNB, 28.9 ± 6.6 weeks cACB, P = .087).

CONCLUSIONS

We found few differences in postoperative analgesic requirements when comparing patients who underwent ACLR with hamstring autograft with a cACB to those who underwent a similar procedure with a cFNB. Return of quadriceps strength and function by six months did not appear to vary with regional technique, either cACB or cFNB, employed at surgery.

LEVEL OF EVIDENCE

III, Retrospective comparative study.

Effects of adductor canal block versus femoral nerve block in patients with anterior cruciate ligament reconstruction: A protocol for a systematic review and meta-analysis

OBJECTIVE

It is reported that both adductor canal block (ACB) and femoral nerve block (FNB) are commonly used methods for postoperative analgesia in anterior cruciate ligament (ACL) reconstruction. Currently, no record has compared the efficacy of postoperative pain relief and the influence to quadriceps strength between them. This study aims to provide a protocol to compare the efficacy and safety between ACB and FNB for the postoperative analgesia of ACL reconstruction.

METHODS

This study will be performed in accordance with the guideline of the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols. Online databases including PubMed, Embase, Web of Science, Cochrane Library, Wanfang database, and the Chinese National Knowledge Infrastructure database will be systematically searched from their inception up May 31, 2019. All randomized controlled trials will be included in present meta-analysis. The quality of enrolled literatures will be evaluated by using the Cochrane Collaboration Risk of bias Tool. Statistical analysis will be calculated by the Review Manager 5.3.

RESULTS

This review will investigate the efficacy and safety of ACB compared with FNB in patients undergoing ACL reconstruction. The primary outcomes are visual analog scale, cumulative opioid consumption during 24 hours after surgery, numerical rating scale, and the time to first straight-leg raise. The secondary outcomes include maximal voluntary isometric contraction, stretching torque at 3, 6 months' follow-up, and adverse effects.

CONCLUSION

Findings of this systematic review and meta-analysis will summarize the current evidence in postoperative analgesia for ACL reconstruction and also provide implications for clinical practice.

Adductor Canal Block Versus Femoral Nerve Block for Pain Control After Anterior Cruciate Ligament Reconstruction: A Prospective Randomized Trial

BACKGROUND

Femoral nerve block (FNB) is a commonly performed technique that has been proven to provide effective regional analgesia after anterior cruciate ligament (ACL) reconstruction. The adductor canal block (ACB) uses a similar sensory block around the knee while avoiding motor blockade of the quadriceps muscles.

PURPOSE/HYPOTHESIS

The purpose of our study was to compare the efficacy of FNB versus ACB for pain control after ACL reconstruction. It was hypothesized that there would be no difference in pain levels or opioid requirements between the 2 groups.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

We performed a prospective, double-blinded, randomized controlled trial. Sixty patients undergoing primary ACL reconstruction with bone-patellar tendon-bone autograft were randomized to receive either an ACB or an FNB preoperatively. The primary outcomes assessed were pain levels (visual analog scale) and narcotic requirements for 4 days after surgery. Secondary outcomes included ability to perform a straight leg raise in the recovery room and difference in thigh circumference between the operative and nonoperative leg measured at 7 days postoperatively.

RESULTS

Morphine requirements were less in the ACB group in the first 4 hours postoperatively ( P = .02). Aside from this time interval, no differences were found between the 2 groups with regard to opioid requirements and pain scores at any other time. Similarly, no differences were noted in patients' ability to perform a straight leg raise in the recovery room ( P = .13) or in thigh circumference at the first postoperative visit ( P = .09).

CONCLUSION

The results of our study suggest similar efficacy in perioperative pain control with the use of an ACB for ACL reconstruction when compared with FNB. The potential long-term benefit of quadriceps preservation with the ACB is worthy of future study.

REGISTRATION

NCT03033589 (ClinicalTrials.gov identifier).

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.

Quadriceps Strength Deficits After a Femoral Nerve Block Versus Adductor Canal Block for Anterior Cruciate Ligament Reconstruction: A Prospective, Single-Blinded, Randomized Trial

Background:

Peripheral nerve blocks, particularly femoral nerve blocks (FNBs), are commonly performed for anterior cruciate ligament (ACL) reconstruction. However, associated quadriceps muscle weakness after FNBs is well described and may occur for up to 6 months postoperatively. The adductor canal block (ACB) has emerged as a viable alternative to the FNB, theoretically causing less quadriceps weakness during the immediate postoperative period, as it bypasses the majority of the motor fibers of the femoral nerve that branch off proximal to the adductor canal.

Purpose/Hypothesis:

This study sought to identify if a difference in quadriceps strength exists after an ACB or FNB for ACL reconstruction beyond the immediate postoperative period. Beyond the immediate postoperative period, we anticipated no difference in quadriceps strength between patients who received ACBs or FNBs for ACL reconstruction.

Study Design:

Randomized controlled trial; Level of evidence, 1.

Methods:

A total of 102 patients undergoing primary ACL reconstruction using a variety of graft types were enrolled between November 2015 and April 2016. All patients were randomized to receive an ACB or FNB before surgery, and the surgeon was blinded to the block type. All patients underwent aggressive rehabilitation without functional bracing postoperatively. The time to the first straight-leg raise was reported by the patient. Isokinetic strength testing was performed at 3 and 6 months postoperatively.

Results:

Data for 73 patients were analyzed. There was no significant difference in patient demographics of age, body mass index, sex, or tourniquet time between the FNB (n = 35) and ACB (n = 38) groups. The mean time to the first straight-leg raise was similar, at 13.1 ± 1.0 hours for the FNB group and 15.5 ± 1.2 hours for the ACB group (P = .134). The mean extension torque at 60 deg/s increased significantly for both the ACB (53.7% ± 3.4% to 68.3% ± 2.9%; P = .008) and the FNB (53.3% ± 3.3% to 68.5% ± 4.1%; P = .006) groups from 3 to 6 months postoperatively. There was also no significant difference in mean extension torque at 60 deg/s or 180 deg/s between the FNB and ACB groups at 3 and 6 months. There were no significant differences in postoperative complications (infection, arthrofibrosis, retear) between groups.

Conclusion:

Although prior studies have shown immediate postoperative benefits of ACBs compared with FNBs, with a faster return of quadriceps strength, in the current study there was no statistically or clinically significant difference in quadriceps strength at 3 and 6 months postoperatively in patients who received ACBs or FNBs for ACL reconstruction.

Endogenous Opiates and Behavior: 2016

This paper is the thirty-ninth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2016 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.

Isokinetic Strength Deficit 6 Months After Adductor Canal Blockade for Anterior Cruciate Ligament Reconstruction

Background

Recent evidence shows a delayed return to sport in children and delayed quadriceps recovery in both adults and children who have undergone anterior cruciate ligament (ACL) reconstruction with concomitant femoral nerve blockade (FNB) compared with those who had no blockade. We evaluated the use of adductor canal blockade (ACB), as an alternative to FNB, at the time of ACL reconstruction.

Hypothesis

Patients who receive ACB will have greater isokinetic strength at 6 months postoperative compared with patients who receive FNB at the time of ACL reconstruction.

Study Design

Cohort study; Level of evidence, 3.

Methods

A retrospective record review was performed at a single academic medical center to identify all patients aged ≥16 years who had undergone ACL reconstruction with blockade between January 2010 and January 2015. Exclusion criteria included (1) non-sports medicine fellowship-trained surgeon performing the procedure, (2) continuous nerve catheter or concurrent epidural used, (3) revision ACL reconstruction or multiligament reconstruction as the index procedure, (4) previous contralateral ACL reconstruction, (5) concurrent microfracture, and (6) additional surgery within the 6-month outcome period that affected recovery. Isokinetic strength testing was performed using a computerized dynamometer, measuring total work at fast speed and peak torque at slow speed at 6 months; results were evaluated as a percentage of the nonoperative side. Multivariate regression analysis was used to evaluate the effect of block type on isokinetic strength outcome variables, controlling for age, sex, body mass index, graft type, and surgeon.

Results

There were 230 patients receiving FNB and 30 patients receiving ACB included in the study. The multivariate regression analysis identified a greater side-to-side deficit in extension total work for the ACB group compared with the FNB group (P = .040), after controlling for age, sex, body mass index, graft type, and surgeon.

Conclusion

Compared with FNB, ACB for ACL reconstruction is associated with a persistent fast-activation isokinetic strength deficit at 6 months after surgery. This is the first study to compare FNB to ACB, and results are concerning for patients planning an early return to sport.

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.