Ultrasound Guided Single Shot Adductor Canal Block (ACB) Versus Single Shot Femoral Nerve Block (FNB) for Postoperative Analgesia After Arthroscopic Anterior Cruciate Ligament (ACL) Reconstruction in Pediatrics
Phase: NA
Conditions: Post-operative Pain, Quadriceps Muscle Strength
Sponsor: Akron Children's Hospital

AKRON CHILDREN'S HOSPITAL 
Ultrasound Guided Single Shot Adductor Canal Block (ACB) 
Versus Single Shot Femoral Nerve Block (FNB) for Postoperative 
Analgesia after Arthroscopic Anterior Cruciate Ligament (ACL) 
Reconstruction in Pediatrics 
NCT03053401 
 
 
10/3/2019 
 
 
 
 
 

 
+Ultrasound Guided Single Shot Adductor Canal Block (ACB) 
Versus Single Shot Femoral Nerve Block (FNB) for Postoperative 
Analgesia after Arthroscopic Anterior Cruciate Ligament (ACL) 
Reconstruction in Pediatrics 
 
 
 
 
 
 
ABBREVIATIONS 
ACL   Anterior Cruciate ligament  
ACB    Adductor Canal Block 
ACH   Akron Children’s Hospital 
AE 
Adverse Event 
ASA  
American Society of Anesthesiologist 
FNB   Femoral Nerve Block 
GE       General Electric 
HIPPA   Health Insurance Portability and Accountability Act  
IRB 
Institutional Review Board 
Kgf     Kilogram-force   
NS        Numeric Scale   
PACU   Post Anesthesia Care Unit 
PHI    Protected Health Information 
PI        Principal Investigator  
POD    Post-operative Day 
PONV  Post- Operative Nausea and Vomiting 
PNB    Peripheral Nerve Block 
SAE 
Serious Adverse Event 
 
SRF 
Study Report Form 
 

 
 
1.0      INTRODUCTION 
Motor preservation with adequate analgesia has become the optimal postoperative goal in 
orthopedic surgeries, and in particular, knee surgeries. This enables earlier physical therapy, 
faster recovery and shorter hospital stays.  Both ultrasound guided ACB and FNB have been 
used to provide postoperative analgesia for knee surgeries including anterior knee reconstruction 
(1,2,12). To our knowledge, no comparison has been made between these blocks in relation to 
postoperative quadriceps muscle strength, or duration and quality of postoperative analgesia for 
arthroscopic ACL reconstruction in pediatrics. ACB predominantly blocks the sensory 
component of the femoral nerve without much effect on the motor component.  Hence, it may 
lead to less quadriceps muscle weakness, early postoperative mobilization and a decrease in the 
incidence of postoperative fall (3, 4). With the advent of ultrasonography, the adductor canal can 
be easily visualized at the mid-thigh level, allowing performance of adductor canal block (ACB) 
with a high success rate (5). In recent years, ACB has been successfully used for postoperative 
pain control after knee surgery (5-7). Anatomical study demonstrated that the adductor canal 
may serve as a conduit for more than just the saphenous nerve, possibly including the vastus 
medialis nerve, medial femoral cutaneous nerve, articular branches from the obturator nerve, as 
well as the medial retinacular nerve (8, 9). Thus, the sensory change is not limited to the 
distribution of the saphenous nerve (8) but includes the medial and anterior aspects of the knee 
from the superior pole of the patella to the proximal tibia. In addition, recent evidence 
demonstrating of persistent strength deficits in patients receiving FNB further underscores the 
need for 
effective alternatives(10)This prospective, double-blinded, randomized, controlled study will test 
the hypothesis that ACB would be associated with less quadriceps motor weakness than FNB at 
4 hour  post block. We also hypothesize that ACB will   provide analgesia to the anterior knee 
that is not inferior to FNB and not different in opioid requirement at 4 and 24 hours after 
Peripheral Nerve Block (PNB) . 
 
 
 
2.0     STUDY OBJECTIVES 
2.1 Hypothesis 
ACB would be associated with less quadriceps motor weakness than FNB and provide 
analgesia that is not inferior to FNB in quality or duration as determined by Numeric 
Scale (NS) pain scores and opioid use at 4 and 24 hours  post PNB. 
 
2.2 Objectives 
To compare FNB and ACB regarding: 
1-Quadriceps muscle strength on both sides (surgical and non –surgical) in the 
immediate pre-operative period) and at 4 hours after PNB. 

2-Pain scores at anterior knee at 4 hours and 24 hours after PNB as assessed by 
Numeric Scale (NS) pain scoring system. Also pain site other than the anterior knee 
will be recorded and specified (posterior knee, calf, leg) 
3- Total opioid consumption at 4 and 24 hours after PNB. 
 
 
 
 
3.0    STUDY DESIGN 
 
     
3.1 Randomized, double blinded, single center clinical trial. A total of 52 pediatric patients 
(ASA 1or 2), aged between 8 to 18 years, for elective ACL reconstruction at Akron 
Children’s Hospital ( ACH ) will be enrolled in the study.  Patients will be randomly 
assigned to one of two groups, A (26 patients) or B (26 patients). Group A patients will have 
ultrasound guided ACB and group B will have ultrasound guided FNB after induction of 
anesthesia. Quadriceps strength of both legs will be assessed by placing the dynamometer on 
the anterior of the ankle, between the malleoli. Patients will be instructed to extend their legs 
three times each, with a 30 seconds pause between each attempt as described by Maffiuletti 
(11).  The assessment will be performed in the pre-operative period and will be repeated 
postoperatively at 4 hours after PNB. Intraoperative, all patients will receive fentanyl 1-2 
mcg/kg and/or morphine 0.05 mg/kg. All patients will receive adjuvant analgesic 
medications in the form of IV Tylenol 10-12.5 mg /kg (maximum 1 gm) after the induction 
of anesthesia. Also, with start of skin closure, patients will receive IV Ketorolac 0.2-0.3 
mg/kg, maximum of 15 mg, unless contraindicated. After emergence from anesthesia, all  
patients will be observed in the post-operative period by an observer unaware of the 
technique of analgesia used. Pain will be assessed using the NS.  Postoperatively, PCA 
morphine pumps will be attached to patients. A loading dose of 0.05 mg/kg to a maximum of 
5 mg will be administered in the Post Anesthesia Care unit (PACU) as needed, followed by 
demand interval dosing of 0.015 mg/kg every 10 minutes as demanded by the patient .Four-
hours limits for morphine will be set at 0.35 mg/kg. No continuous infusion and no adjuvant 
NSAIDs or acetaminophen will be administered in PACU. Rescue morphine dosing will be 
ordered via PCA pump at 0.05 mg/kg ( repeated once as needed) and will be available every 
two hours as needed by pain assessment ( for a NS  ≥ 4 ) or patient request. Diazepam 0.03 
mg/kg IV will be available every 4 to6 hours as needed for muscle spasm or anxiety.  
Patients will be considered ready for discharge from hospital when all the following criteria 
are met: Child is alert, oriented, stable vital signs, and can tolerate clear liquids, with no 
nausea or vomiting, and good pain control (no to mild pain). The evaluation for meeting the 
discharge criteria will be done after one hour from arrival in PACU and every 30 minutes 
thereafter until the patient meets all the discharge criteria.  After discharge, parents will be 
instructed to give the patient oxycodone 0.1 mg /kg PO q 4   hours as needed for pain. 
Acetaminophen10mg/kg q 4 hours and/or ibuprofen 10 mg/kg q 4  hours may be 

administered as needed for residual pain, not exceed 2400 mg in 24 hours. The total dose of 
oxycodone, ibuprofen and acetaminophen will be recorded per parents for a total of 24 hours 
after PNB. Pain scores and pain site will be also recorded by parent at 24 hours post -block.  
The data for total opioids used in the first 24 hours after PNB and pain score at 24 hours will 
be collected from parents by phone call.  
 
 
 
 
3.2   Study Endpoints 
       1-Quadriceps muscle strength on both sides (surgical and non-surgical) pre-operatively 
and at 4 after PNB                                                                                                                                                
       2- Total morphine/morphine equivalent at 4 and 24 hours after PNB. 
       3-Pain scores at anterior knee via NS at 4 and 24 hours after PNB. 
           
 
     
 3.3 Primary Safety Endpoints 
 Adverse events related to both procedures (ACB and FNB) will be recorded (Please refer to 
section 8). Known possible adverse events and complications are those associated with peripheral 
nerve blocks in general and includes potential for bleeding ( hematoma) , infection, nerve injury , 
allergy to the local anesthetics (ropivacaine) or adjuvant medication ( methylprednisolone) used 
to achieve the block.  
 
           
 
4.0 SUBJECT SELECTION AND WITHDRAWAL 
4.1 Inclusion criteria:  
            1-ASA I or II  
            2- Age 8 to 18 years  
3-All research subjects must have an acceptable legally authorized representative   
capable of giving consent on the subject’s behalf if under 18 years old. 
 
           4.2 Exclusion criteria:  
Those who were unable to use a standard 0-10 NS., those with infection at the site of the 
block; those with bleeding disorders; those with allergy to the drugs used to perform the 
block (ropivacaine , methylprednisolone); and those who refused a nerve block or 
enrollment in the study.  
 

            4.3 Subject recruitment: 
The surgical schedule will be reviewed for potential research subjects. Potential subjects will 
be seen in the orthopedic office prior to the scheduled surgery. If they are found to be eligible 
to participate in the study, the authorized legal representative(s) will be given the choice to 
participate in the study. The study will be explained to the authorized legal representative(s).  
An informed consent will be provided for review by the authorized legal representative (s). 
They will be given a phone number to contact in case they have any questions regarding the 
study. If they agree to participate in the study, the authorized legal representative (s) will be 
requested to sign and date the informed consent   prior to the scheduled surgery. Patient 
ascent to the study may be also requested if needed. 
         4.4 Patient withdrawal: 
Patient and/or authorized legal representative may withdraw from the trial at any time and 
for any reason. Some possible reasons for withdrawal include: 
1- Patient  and/or authorized legal representative withdraws consent to continued 
participation in the trial 
2-  Patient develops a complication related to anesthesia and/or surgery  
 
4.5 Data Collection and Follow Up for Withdrawn Subjects: 
All subjects that withdraw from the study after randomization and/or performance of the 
block will be asked if they will allow for the collection of data. This will keep the 
subjects in their already assigned group thereby allowing for the collection and analysis 
of data with the intention to treat principle. However, if the subject does not want to 
allow collection of data, all follow-up must stop. At that time the subject will be 
considered as drop out.  
 
 
 
 
  
 
 
5.0 STUDY TREATMENT 
           5.1 Description: 
The patient will be randomly assigned to one of two groups, A or B. Group A patients 
will have ultrasound guided ACB performed at mid-thigh level and  group B will have 
ultrasound guided FNB, with nerve stimulator confirmation with the type of motor 
response (e.g., quadriceps, patellar) and the minimum current needed to be  recorded.   
Both blocks will be performed under general anesthesia.  Both group will have 
ropivacaine 0.2 % ( 0.5 ml/kg, maximum of 30   ml and methylprednisolone acetate 1  
mg/kg , maximum of 40 mg ).Both blocks will be performed using  a 22-gauge 2-inch 
Stimuplex  A needle; ; B. Braun Medical Inc., Melsungen, Germany).Both blocks will be 

performed using  linear ultrasound transducer, General Electric ( GE). Ultrasound 
pictures will be obtained to Verify proper local anesthetic placement. Unfortunately, 
surgeons are not able to determine the type of procedure needed to correct ACL injury, 
until after knee arthroscopy is performed under general anesthesia ACL reconstruction 
using a hamstring graft, which is the surgical procedure used in this study may not always 
be possible to perform by the surgeon. The surgical alternative of ACL reconstruction is 
ACL repair, which seldom is done by our surgeon. Patient undergoing ACL 
reconstruction can experience pain in the posterior aspect of the knee, in the distribution 
of the sciatic nerve. This is due to the hamstring graft. In contrast to the anterior knee 
pain covered by both ACB and FNB, posterior knee pain is controlled with IV/oral 
analgesic. This is why recording the site of the knee pain is important to determine the 
PNB success. Due to the inability to determine beforehand, the type of procedure to be 
performed, we decided therefore to continue the study procedures and data collection on 
both ACL reconstruction and ACL repair. The statistical analysis will include only 
patients that undergo ACL reconstruction. For the other patients that undergo ACL repair, 
data will be collected but not included in the statistical analysis. The data from these 
patients may be used as a pilot for future research. 
 
. 
 
5.2 Method for Assigning Subjects to Treatment Regimen 
Random allocation for one of the two treatments will be achieved using sealed envelope 
assigned by an external third party not involved in the study to ensure allocation 
concealment. 
 
5.3 Blinding of Study Procedure: 
Both the observer and the patient (and the legally authorized representative) will be blinded 
to the type of block performed. 
 
 
 
 
 
6.0 STUDY PROCEDURES 
 
 
Following emergence from anesthesia, all the patients will be observed in the post-operative 
period by an observer unaware of the technique of analgesia used. Children will be evaluated 
in the PACU every 10 minutes. Pain will be assessed using the NS.  PCA morphine pumps 
will be attached to patients’ IV. A loading dose of 0.05 mg/kg to a maximum of 5 mg will be 
administered in the PACU as needed, followed by demand interval dosing of 0.015 mg/kg 

every 10 minutes.as demanded by the patient .Four-hours limits for morphine will be set at 
0.35 mg/kg. No continuous infusion and no adjuvant NSAIDs or acetaminophen will be 
administered. Rescue morphine dosing will be ordered via PCA pump at 0.05 mg/kg ( 
repeated once as needed) and will be available every two hours as needed by pain assessment 
( for a NS  ≥ 4 ) or patient request. Diazepam 0.03 mg/kg IV will be available every 4 to6 
hours as needed for muscle spasm or anxiety.  Patients will be considered ready for discharge 
from hospital when all the following criteria are met (but actual discharge will not be allowed 
before 4 hours after PNB for the purpose of the study):  
Child is alert, oriented, stable vital signs and would tolerate clear liquid, with no nausea or 
vomiting and with good pain control. 
 After discharge, parents will be instructed to give the child oxycodone tablets/elixir 0.1 mg 
/kg PO q 3   hours as needed for pain. In addition, acetaminophen 10mg/kg q 4 hours PRN 
and/or ibuprofen 10 mg/kg q 6 hours PRN may be administered for any residual pain. 
Quadriceps muscle strength will be recorded at 4 hours after PNB in the PACU. 
Pain scores using the NS and total opioids consumption will be recorded at 4 and 24 hours 
post- block. The assessment at 4 hours will be done in the PACU and the assessment at 24 
hours will be done via phone call. 
 
7.0   ANALYTICAL PLAN 
   
7.1 Summary Statistics will be provided for all variables.  Examination of continuous data 
will include normality testing as well as assessment of potential outliers.  Statistical testing 
will be based upon distributional shape, but for purpose of analytical planning and sample 
size analysis normality of distributions will be assumed.   
To examine for potential differences in quadriceps motor strength (QMS) between the two 
groups (ACB, FNB),  two change scores will be created and analyzed via T-Test for Equal 
and Unequal Variances with appropriate Bonferroni adjusted alpha testing paired 
difference at two distinctive time points.  Assuming no statistically significant baseline 
differences between the two groups the QMS Change scores will be a) Baseline to 4 hours.  
Sample size analysis will be based upon testing of the QMS Change scores.  Non-
inferiority of ACB to FNB in analgesia provided will be assessed by examination of pain 
scores.  Non-inferiority of ACB compared with FNB is defined as the mean ACB - NRS 
pain score not higher than the mean FNB – NRS pain score by an amount of 1.6.  (Kim, 
2014) Pain scores and pain site will be individually examined at the 4 hour and 24 hour 
post – operative time points with appropriate Bonferroni adjusted alpha.  In addition, a 
change in pain score from 4 to 24 hours will be created and evaluated for potential 
difference between groups.   
Total opioid consumption as measured in morphine equivalents will be assessed at the 24 
hour post-operative time point to determine whether a difference exists.  Opioid 
consumption will also be examined by creating a change score from 4 to 24 hour 
consumption and comparing between the groups.   
 

Examination of subjects who undergo reconstruction will include descriptive statistics.   
 
Any other testing done will be exploratory in nature based upon examination of data and 
results of testing described above.   
 
All testing will be completed utilizing SAS 9.4 © software and evaluated at the Type I 
Error Rate of alpha = 0.05 level for statistical significance unless otherwise noted.   
 
7.2 POWER AND SAMPLE SIZE ANALYSIS 
Sample size analysis is based upon utilization of the T-Test to analyze for potential 
differences in QMS Change Scores between the two groups.  Calculated effect size = 1.1 
based upon reported quadriceps strength mean (SD) as 7.3 (5.4) for ACB and 2.2 (3.8) for 
FNB utilizing information from study by Kim et al. (13). To account for analysis of paired 
differences at two time points the α = Type I Error Rate of 0.05 is adjusted using 
Bonferroni’s method to 0.025. Power set at 80%.   
Population differences from cited study limit the ability to calculate sample size requirements 
accurately.  Considerations must also be taken into account for potential departures from 
normality, non-evaluable subjects / drop outs and potential effect size smaller than calculated.  
Therefore the minimum recommended sample size for this study is 50 subjects (25 in each 
arm).  Refer to tables below for more information regarding power and sample size. 
Minimum sample size required for given effect sizes 
 Effect 
Size 
n1 
n2 
N 
0.7 
40 
40 
 80 
0.9 
25 
25 
50 
1.1 
18 
18 
36 
 
Power approximations for varying effect sizes and sample sizes 
Effect Size 
Alpha 
N 
Approximate 
Power 
1.1 
0.025 
36 
80% 
1.1 
0.025 
30 
74% 
1.1 
0.025 
24 
62% 
0.9 
0.025 
50 
80% 
0.9 
0.025 
40 
69% 
0.9 
0.025 
30 
54% 
0.7 
0.025 
80 
80% 

0.7 
0.025 
70 
74% 
0.7 
0.025 
60 
66% 
 
Sample size analysis was completed utilizing the “pwr” package in R 3.1.2 ©.    
 
7.3 Randomization Table 
A randomization table for up to 60 patients will be provided to the person responsible for 
blinding the study.  Randomization table completed using utilizing SAS 9.4 © software. 
 
8  SAFETY AND ADVERSE EVENTS 
 
8.1 Definitions 
Adverse events related to both procedures (ACB and FNB) will be recorded. Known possible 
adverse events and complications are those associated with peripheral nerve blocks in general, 
and includes potential for bleeding ( hematoma) , infection, nerve injury , allergy to the local 
anesthetics or adjuvant medications used to achieve the block.  
Also, any unexpected side effects suspected to be related to the study will be reported. 
8.2 Recording of Adverse Events 
The investigator will seek information on adverse events by specific questioning and, as 
appropriate, by examination. Information on all adverse events will be recorded 
immediately in the source document, and also in the appropriate adverse event section of 
the Study Report Form (SRF).  All clearly related signs, symptoms, and abnormal 
diagnostic procedures results will also be recorded in the source document.  
The clinical course of each event will be followed until resolution, stabilization, or until it 
has been determined that the study treatment is not the cause. Serious adverse events that 
are still ongoing at the end of the study period will be followed up to determine the final 
outcome. Any serious adverse event that occurs after the study period and is considered to 
be possibly related to the study treatment or study participation will be recorded and 
reported immediately. 
 
8.3 Reporting of Serious Adverse Events 
 
IRB Notification by Investigator(s) 
 The following four types of events will be reported to IRB:  
1. Adverse events which are serious, unexpected, and related or possibly related to 
participation in the research.  
2. Other unexpected adverse events, regardless of severity, that may alter IRB analysis 
of the risk versus potential benefit of the research and, as a result, warrant 

consideration of substantive changes in the research protocol or informed consent 
process/document.  
3. Unanticipated Problems involving risks to subjects or others or any serious or 
continuing noncompliance with this policy or the requirements or determinations of 
the IRB.” 
 
 
 
 
 
9  DATA HANDLING AND RECORD KEEPING 
9.1    Confidentiality and Privacy 
 
Protected health information (PHI) that will be collected from subjects in this study 
will be name, birth date and medical record number. 
 
Only the PI and the Co-investigator(s) on the study will have an access to this 
information. This information will be kept in a locked box in the anesthesia control office . 
 
None of these PHI will be published or disclosed to any other parties other than the 
investigators participating in the study.  
 
All Informed consents /assents will be also kept in a locked box in the anesthesia office and will 
be kept for reviews for at least 2 years after the publication of the study. 
 
Legal authorized representative of the patient will also be requested to sign “Authorization for 
Release of Information for research” to address Health Insurance Portability and 
Accountability Act (HIPPA) requirements. 
 
 
 
9.2         Source Documents: 
Source documents will include PACU nurse assessment flow sheets, pain score flow sheets and 
medications flow sheets.  Dynamometer measurements for each patient will be also collected 
pre-operatively, and at 4 hours postop. 
 
 
10  STUDY MONITORING, AUDITING AND INSPECTING 
 
10.1 Study Monitoring Plan 
This study will be monitored through a data monitoring committee. 
This is a relatively short study that will be performed over a period of 9-12 months. This 
study offers minimal risk to the patient. The data monitoring committee will include the 
PI, at least one of the co-investigators, the principal statistician, and the principal 
research nurse. 
The data monitoring committee will meet when approximately 25%, 50%, 75% and 
100% of the primary outcomes are observed. The priority of the data monitoring 

committee will be to ensure the safety of the participants in the trial and to ensure the 
integrity of the trial. Also, these meetings will monitor the quality of the collected data to 
assess for weaknesses and errors. If any weakness and/or errors are identified, feedback 
will be provided during these meetings .The investigator(s) will allocate adequate time 
for such monitoring activities. The investigator(s) will also ensure that the monitor or 
other compliance or quality assurance reviewer is given access to all the above noted 
study-related documents. 
 
10.2  Auditing and Inspecting 
The investigator(s) will permit study-related monitoring, audits, and inspections by the 
IRB,  Institutional compliance and quality assurance groups of all study related 
documents (for example, source documents, regulatory documents, data collection 
instruments, study data etc.). Participation as an investigator(s) in this study implies 
acceptance of potential inspection by government regulatory authorities and applicable 
Institutional compliance and quality assurance offices. 
 
 
 
11  REFERENCES 
 
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After Total Knee Arthroplasty :Regional Anesthesia and Pain Medicine 2013; 38:526-532. 
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Arthroplasty . Anesthesiology 2014;120:540-550 
3- Atkinson HD , Hamid Iet al.: Postoperative fall after use of the 3-in-1 femoral nerve block for knee 
surgery : A report of four cases . J Orthop Surg ( Hong Knong)  2008 ; 16 : 381-4 
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12- Abdallah FW, Whelan DB et al., Adductor Canal Block Provides Noninferior Analgesia and Superior 
Quadriceps Strength Compared with Femoral Nerve Block in Anterior Cruciate Ligament 
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arthroplasty: a prospective, randomized, controlled trial. Anesthesiology. 2014;120(3):540-550