A Pilot Study Comparing Anterior Femoral Cutaneous Nerve Blocks to Adductor Canal Blocks in Pediatric Ambulatory Knee Surgeries
Phase: PHASE4
Conditions: Anterior Cruciate Ligament Reconstruction, Medial Patellofemoral Ligament Reconstruction
Sponsor: Hospital for Special Surgery, New York

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A Pilot Study Comparing Anterior Femoral 
Cutaneous Nerve Blocks to Adductor Canal Blocks 
in Pediatric Ambulatory Knee Surgeries 
 
FUNDER: 
Anesthesiology Research Department 
PROTOCOL NO.: 
2024-0582 
VERSION & DATE: 
Version 1, 8/1/2024 
 
 
 
 
 
 
 
 
 
 
 
 
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the prior written consent of the Hospital for Special Surgery.  No other use or reproduction is authorized by Hospital for Special Surgery, nor does 
the Hospital for Special Surgery assume any responsibility for unauthorized use of this protocol. 
 
 
TABLE OF CONTENTS 
TABLE OF CONTENTS ............................................ 2 
PROTOCOL SYNOPSIS ........................................... 4 
1.0 
INTRODUCTION ............................................ 5 
2.0 
OBJECTIVE OF CLINICAL STUDY .............. 5 
3.0 
STUDY HYPOTHESES ................................. 6 
4.0 
STUDY DESIGN ............................................ 6 
4.1 
Study Duration ................................................................................................................ 6 
4.2 
Endpoints ....................................................................................................................... 6 
4.2.1 
Primary outcome ....................................................................................................... 6 
4.2.2 
Secondary outcome(s) .............................................................................................. 6 
4.3 
Study Sites ..................................................................................................................... 6 
5.0 
STUDY POPULATION .................................. 6 
5.1 
Number of Subjects ........................................................................................................ 6 
5.2 
Inclusion Criteria............................................................................................................. 6 
5.3 
Exclusion Criteria ........................................................................................................... 7 
5.4 
Randomization ............................................................................................................... 7 
6.0 
PROCEDURES .............................................. 7 
6.1 
Surgical Procedure ......................................................................................................... 7 
6.2 
Medical Record Requirements ....................................................................................... 7 
6.3 
Data Collection ............................................................................................................... 7 
6.4 
Schedule of Assessments .............................................................................................. 9 
7.0 
STATISTICAL ANALYSIS ........................... 10 
8.0 
ADVERSE EVENT ASSESSMENT ............. 10 
8.1 
Adverse Event (AE) ...................................................................................................... 10 
8.2 
Serious Adverse Events (SAE) .................................................................................... 10 
8.3 
Adverse Event Relationship ......................................................................................... 10 
8.4 
Adverse Event Recording ............................................................................................ 10 
8.5 
Adverse Event Reporting ............................................................................................. 10 
9.0 
INVESTIGATOR RESPONSIBILITIES, RECORD 
AND REPORTS ....................................................... 10 
9.1 
Subject Consent and Information ................................................................................. 10 

 
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9.2 
Subject Data Protection ............................................................................................... 11 
9.3 
Staff Information ........................................................................................................... 11 
9.4 
Protocol Reviews.......................................................................................................... 11 
10.0 
REFERENCES .......................................... 11 
 
 
 

 
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PROTOCOL SYNOPSIS 
Protocol Title: 
A Pilot Study Comparing Anterior Femoral Cutaneous Nerve 
Blocks to Adductor Canal Blocks in Pediatric Ambulatory Knee 
Surgeries 
Protocol Number: 
2024-0582 
Protocol Date: 
6/14/2024 
Sponsor: 
Anesthesiology Research Department 
Principal 
Investigator: 
Kathryn DelPizzo 
Products: 
N/A 
Objective: 
The goal of this pilot study is to collect information on the effects 
of the Anterior Femoral Cutaneous Nerve Block (AFCNB) 
compared to the Adductor Canal Block (ACB) in adolescent 
patients undergoing ambulatory knee surgery at the Hospital for 
Special Surgery. 
Study Design: 
A double-blinded, pilot parallel group-randomized trial (GRT) 
Enrollment: 
60 subjects 
Subject Criteria: 
1. 8-18 years old at the time of surgery 
2. Patients 40kg and above 
3. ACL repair of MPFL reconstruction surgery with 
participating surgeons 
Study Duration: 
1. 3 years (anticipated) 
Data Collection: 
• 
Demographics, patient-reported outcomes, pain and 
satisfaction survey/questionnaires 
Outcome 
Parameters: 
• 
Postoperative function (motor strength in quadriceps) 
• 
Opioid consumption, NRS pain at rest & with ambulation, 
pain expectation scale, satisfaction with pain 
management, postoperative sensation, postoperative 
function 
Data Evaluation: 
PACU, post operative 6 hrs, 24 hrs, 48 hrs, 7 days, 14 days, 6 
weeks, 6 months 
Statistical Analysis: 
For this pilot study, we are incorporating the “rule of 12” for 
continuous outcome in our sample size. 
A sample size of n=15 per treatment group, to account for 
potential attrition, for a total of 60 patients. 
 
 
 

 
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1.0 INTRODUCTION 
 
The current focus and trend of pediatric postoperative pain management research 
involves increased opioid stewardship and regional anesthesia use [1-3]. Previous studies 
have highlighted the importance of regional anesthesia during knee surgery such as ACL 
reconstruction, suggesting that perioperative adductor canal block is safe [4] for pediatric 
patients, and beneficial for reducing pain and minimizing muscle weakness in the immediate 
postoperative in adult patients [5-10].  Controversy remains on the potential residual effects on 
functional outcomes with adult patients receiving ACBs, and there is limited data on 
outcomes in younger patients.  A study by Christensen et al suggested that there is 
prolonged postoperative quadriceps weakness after ACL reconstructions in adults who 
received an ACB [11]. In a recent retrospective study evaluating quadriceps and hamstring 
strength in adolescent patients who underwent primary unilateral ACL between July 2008 
and January 2018 at a single institution, isokinetic quadriceps deficits were measured at 4-8 
months postoperatively in patients who received either a femoral nerve block (n = 36), ACB 
(n = 31) or no block. The authors found no significant difference in isokinetic quadriceps 
function among the three groups (@ 5.61 ± 2 months), though they identified a trend 
towards more negative value in the ACB group suggesting of greater muscle weakness.  
 
There was, however, a significantly lower knee flexion peak torque in the hamstring 
of patients who received the ACB compared to FNB group. Limitations include the 
retrospective nature of the study, procedures limited to hamstring autografts, inclusion of 
patients who did or did not have meniscal repairs, variations in anesthetic technique and 
doses, as well as in postoperative physical therapy approaches. 
 
Targeting the anterior femoral cutaneous nerve (AFCNB) is a motor sparing 
technique that provides incisional pain relief but also targets the fascia lata which is integral 
to the knee and surgically traumatized during knee surgeries. The entire kneecap is blocked 
when targeting the AFCN in the medial thigh.13, 14 
 
No prospective randomized controlled studies have been conducted in pediatric ACL 
and MPFL reconstruction patients that compare pain intensity levels, opioid consumption 
and muscle strength in the acute perioperative period and later time points with different 
peripheral nerve blocks. To our knowledge, this will be the first pediatric study to 
prospectively collect data from patients receiving AFCNB vs. ACB. 
2.0 OBJECTIVE OF CLINICAL STUDY 
There is scant literature on the efficacy of peripheral nerve blocks or the comparative 
effectiveness of anesthesia and analgesia techniques in pediatric/adolescent patients 
undergoing orthopedic procedures, particularly ambulatory knee procedures such as 
anterior cruciate ligament (ACL) reconstruction. The Pediatric Regional Anesthesia Network, 
PRAN, to which the study team has contributed information, has focused on safety, rather 
than efficacy, of regional techniques. The efficacy of these regional techniques in this 
demographic has not been investigated and therefore represents a vital knowledge gap.  
Moreover, there is practice variation at HSS with regard to how patients are blocked for 
ACL reconstruction surgery. While most surgeons request an adductor canal block (ACB), 
others do not, citing concerns with potential immediate and persistent functional motor 
deficits. Given the innervation to the knee and concern with residual functional impairment, 

 
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the goal of our pilot study is to collect preliminary information comparing the AFCNB vs 
ACB, in the hopes of using this data to power a larger randomized controlled trial to 
rigorously study this clinical question. 
3.0 STUDY HYPOTHESES 
As this is a pilot study, no formal hypothesis testing will be performed. 
4.0 STUDY DESIGN 
A double-blinded, pilot parallel group-randomized trial (GRT) 
4.1 
Study Duration 
Approximately 3 years 
4.2 
Endpoints 
Primary and secondary outcomes 
4.2.1 
Primary outcome 
• 
Postoperative function (motor strength in quadriceps) 
4.2.2 
Secondary outcome(s) 
• 
Cumulative opioid consumption 
• 
NRS at rest & with ambulation 
• 
Pain expectation scale 
• 
Satisfaction with Pain Management 
• 
Postoperative sensation 
• 
Postoperative function 
4.3 
Study Sites 
Hospital for Special Surgery, New York, New York 
5.0 STUDY POPULATION 
5.1 
Number of Subjects 
60 
 
5.2 
Inclusion Criteria 
Subjects of either gender will be included if they: 
 
1. 8-18 years old at the time of surgery 
2. Patients 40kg and above 
3. ACL repair of MPFL reconstruction surgery with participating surgeons 
4.  

 
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5.3 
Exclusion Criteria 
Subjects will be excluded from the study if they: 
1. Revision surgery 
2. Bilateral surgery 
3. General anesthesia 
4. Contraindications to any part of the study protocol 
5. Relevant pre-existing neurological deficit 
6. Chronic pain 
5.4 
Randomization 
 30 ACL subjects, randomized to either Adductor Canal Block (15) or Anterior Femoral 
Cutaneous Nerve Block (15). 
 
30 MPFL subjects, randomized to either Adductor Canal Block (15) or Anterior Femoral 
Cutaneous Nerve Block (15). 
6.0 PROCEDURES 
6.1 
Surgical Procedure 
Anterior Cruciate Ligament (ACL 
Medial Patellofemoral Ligament (MPFL) 
6.2 
 Medical Record Requirements 
Basic demographic variables: Name, MRN, DOB, Race, Sex, Ethnicity, Height, Weight, BMI 
6.3 
Data Collection 
 
The following data will be collected: 
 
Pre-operative/Baseline 
• 
basic demographic data 
• 
patient weight & height, BMI 
• 
NRS pain at rest & with ambulation 
 
Surgical procedure 
• 
date of surgery 
• 
type of surgery 
 
Follow-up visits (PACU, POD 1-4, 7, 2 wks, 6 wks, 3 mo, & 6 mo) 
• 
NRS pain at rest & with ambulation 
• 
Opioid consumption 
• 
Patient satisfaction with pain management 
• 
Pain expectation 
• 
Postoperative sensation 
• 
Quadriceps strength (dynamometer) 

 
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• 
Range of motion (goniometer) 
• 
PROMIS-10: physical function score 
 

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6.4 
Schedule of Assessments 
 
*=Patient will be re-evaluated by the investigator as per standard follow-up post-operatively at the following intervals
Procedures 
Before 
DOS 
Pre-op 
(Holding area) 
POD 0 
POD 1-2 
POD 7 
POD 14 
2 weeks, 6 
weeks, 3 mo, 6 
mo, 1 yr 
Informed Consent & Eligibility Review 
X 
 
 
 
 
 
 
Obtain Assent from minor patient and 
Consent from parent or guardian 
 
X 
 
 
 
 
 
Randomization 
 
X 
 
 
 
 
 
NRS Pain Scores (rest & ambulation) 
 
X 
X 
X* 
X 
X 
 
Opioid consumption 
 
 
X 
X* 
X 
X 
 
Patient satisfaction w/pain 
management 
 
 
 
 
X 
 
 
Pain expectation 
 
 
X 
X* 
X 
X 
 
Measure of sensation 
 
 
 
 
 
X 
X* 
Measure of function 
 
 
 
 
 
X 
X* 

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7.0 STATISTICAL ANALYSIS 
For this pilot study, we are incorporating the “rule of 12” for continuous outcome in our 
sample size. 
A sample size of n=15 per treatment group, to account for potential attrition, for a total of 60 
patients. 
 
8.0 ADVERSE EVENT ASSESSMENT 
All Adverse Events (AEs) will be reported in the final study report. Definitions for Adverse 
Event (AE) used in this study are listed below and are based on FDA and international 
guidelines: 
 
8.1 
Adverse Event (AE) 
Any untoward medical occurrence in a patient or clinical investigation subject 
administered a pharmaceutical product which does not necessarily have to have a 
causal relationship with this treatment. An adverse event (AE) can therefore be any 
unfavorable and unintended sign (including an abnormal laboratory finding, for 
example), symptom, or disease temporally associated with the use of a medicinal 
(investigational) product, whether or not considered related to the medicinal 
(investigational) product. 
8.2 
Serious Adverse Events (SAE) 
The event is serious and should be reported to FDA when the patient outcome is: 
Death, Life-threatening, Hospitalization (initial or prolonged), Disability or Permanent 
Damage, Congenital Anomaly/Birth Defect, Required Intervention to Prevent 
Permanent Impairment or Damage (Devices), Other Serious (Important Medical 
Events). 
8.3 
Adverse Event Relationship 
Relationship to study: definitely, probably, possibly, not related. 
8.4 
Adverse Event Recording 
All adverse events will be recorded in the adverse event log by the research 
coordinator. 
8.5 
Adverse Event Reporting 
All adverse event reports will be made to the institutional review board as they come 
up/occur. 
9.0 INVESTIGATOR RESPONSIBILITIES, RECORD AND REPORTS 
 
9.1 
Subject Consent and Information 
Research assistants will screen the co-investigating surgeons' patients undergoing ACL 
and MPFL surgeries. Screening will involve reviewing the patient's EPIC chart to ensure 

 
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that they meet the inclusion criteria and are not excluded due to any of the exclusion 
criteria listed. Patients who meet the inclusion criteria will be identified as potential study 
participants. After the investigating anesthesiologists have confirmed the eligibility of all 
potential participants, one of the investigating anesthesiologists will approach the 
potential patients in the pre-operative holding area, explain the rationale for the study, 
and ask if the patient is interested in participating. 
9.2 
Subject Data Protection 
Subject privacy and confidentiality will be maintained through the storage of study data 
in a password-protected computer database maintained by the Research Director and 
accessible only to the principal investigator, in addition to other IRB-approved study 
personnel. Each subject will be assigned a unique study number for identification in 
the study database. This unique study number will not be derived from or related to 
information about the individual. The key linking this unique study number to patient 
identifiers (i.e., name, medical record number, date of birth, registry number) will be 
maintained in a different password-protected database maintained by Research 
Director, to which only the primary investigator will have access. 
9.3 
Staff Information 
Primary Investigator: Kathryn DelPizzo, MD 
Research Coordinator: Pa Thor, PhD, 646-797-8535 
 
9.4 
Protocol Reviews 
Study protocol reviewed and approved by: 
• 
Anesthesiology CRP 
• 
Hospital for Special Surgery Institutional Review Board 
10.0 REFERENCES 
1. Liu SS, Strodtbeck WM, Richman JM, Wu CL. A comparison of regional versus general 
anesthesia for ambulatory anesthesia: a meta-analysis of randomized controlled trials. 
Anesth Analg. 2005;101:1634–1642. 
2. Wang C, Liu LD, Bai X. Bibliometric and Visual Analysis of the Current Status and Trends of 
Postoperative Pain in Children from 1950-2021. J Pain Res. 2022;15:3209-3222. Published 
2022 Oct 14. 
3. Micalizzi RA, Williams LA, Pignataro S, Sethna NF, Zurakowski D. Review of outcomes in 
pediatric patients undergoing anterior cruciate ligament repairs with regional nerve blocks. J 
Pediatr Nurs. 2014 Nov-Dec;29(6):670-8. Epub 2014 Jul 13. PMID: 25089833. 
4. Walker BJ, Long JB, Sathyamoorthy M, et al. Complications in Pediatric Regional 
Anesthesia: An Analysis of More than 100,000 Blocks from the Pediatric Regional Anesthesia 
Network. Anesthesiology. 2018;129(4):721-732. 
5. Yee EJ, Gapinski ZA, Ziemba-Davis M, Nielson M, Meneghini RM. Quadriceps Weakness 
After Single-Shot Adductor Canal Block: A Multivariate Analysis of 1,083 Primary Total Knee 
Arthroplasties. J Bone Joint Surg Am. 2021;103(1):30-36.  
6. Zhao XQ, Jiang N, Yuan FF, Wang L, Yu B. The comparison of adductor canal block with 
femoral nerve block following total knee arthroplasty: a systematic review with meta-analysis. 
J Anesth. 2016;30(5):745-754. 
7. Kuang MJ, Ma JX, Fu L, He WW, Zhao J, Ma XL. Is adductor canal block better than femoral 
nerve block in primary total knee arthroplasty? A GRADE analysis of the evidence through a 

 
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systematic review and meta-analysis. J Arthroplasty. 2017 Oct;32(10):3238-3248.e3. Epub 
2017 May 17. 
8. Jiang X, Wang QQ, Wu CA, Tian W. Analgesic efficacy of adductor canal block in total knee 
arthroplasty: a meta-analysis and systematic review. Orthop Surg. 2016Aug;8(3):294-300 
9. Abdallah FW, Brull R, Joshi GP; Society for Ambulatory Anesthesia (SAMBA). Pain 
Management for Ambulatory Arthroscopic Anterior Cruciate Ligament Reconstruction: 
Evidence-Based Recommendations From the Society for Ambulatory Anesthesia. Anesth 
Analg. 2019;128(4):631-640.  
10. Abdallah FW, Whelan DB, Chan VW, et al. Adductor Canal Block Provides Noninferior 
Analgesia  and Superior Quadriceps Strength Compared with Femoral Nerve Block in 
Anterior Cruciate Ligament Reconstruction. Anesthesiology. 2016;124(5):1053-1064.  
11. Christensen JE, Taylor NE, Hetzel SJ, Shepler JA, Scerpella TA. Isokinetic Strength Deficit 6 
Months After Adductor Canal Blockade for Anterior Cruciate Ligament Reconstruction. 
Orthop J Sports Med. 2017 Nov 8;5(11):2325967117736249. PMID: 29152521; PMCID: 
PMC5680944. 
12. Frazer AR, Chaussé ME, Held M, St-Pierre C, Tsai CY, Preuss R, Descoteaux N, Chan M, 
Martineau PA, Veilleux LN. Quadriceps and Hamstring Strength in Adolescents 6 Months 
After ACL Reconstruction With Femoral Nerve Block, Adductor Canal Block, or No Nerve 
Block. Orthop J Sports Med. 2021 Jul 22;9(7):23259671211017516. doi: 
10.1177/23259671211017516. PMID: 34368383; PMCID: PMC8312176. 
13. Anterior Femoral Cutaneous Nerve Block (Dr. Jeff Gadsden), Accessed from:   
https://www.youtube.com/watch?v=zzj08axeE94 
14. Anterior Femoral Cutaneous Nerve Block (Dr. Amit Pawa); Accessed from: 
https://www.youtube.com/watch?v=bAxMvcTf0kU