Adductor Canal Block Versus Periarticular Bupivicaine Injection in Total Knee Arthroplasty
Phase: PHASE4
Conditions: Osteoarthritis
Sponsor: Columbia University

COVER PAGE 
 
Title: Adductor Canal Block versus Periarticular Bupivacaine Injection in Total Knee Arthroplasty 
NCT Number: NCT02777749 
07/01/2016 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

1. Specific Aims 
In the last decade, the widespread use of regional anesthesia in total knee arthroplasty (TKA), has led to improvements in pain 
control, more rapid functional recovery, and reduced length of stay.1  In recent years many surgeons have transitioned from 
femoral nerve blocks (proximal femoral nerve) to adductor canal blocks (distal femoral nerve) to  maintain a sensory block for 
pain control, while minimizing any motor blockade that is typically seen in proximal femoral nerve blocks, which would hamper 
rehabilitation, and increase risk of falls.2  In addition to regional blocks, which are typically performed in the preoperative setting, 
some surgeons favor an intraoperative periarticular anesthetic injection (PAI), typically with bupivacaine, either in conjuction 
with an adductor canal block, or independently.3–5   In theory, PAI has the advantage of a comparable sensory nerve block as an 
adductor canal block, without the disadvantages and risks, which include prolonged quadriceps weakness, fall risk, and 
neurologic dysfunction.3,6  The purpose of this randomized control trial is to compare the efficacy of adductor canal blocks and 
periarticular bupivacaine injections for pain management in patients undergoing a total knee arthroplasty.   
Specific Aim:  To determine whether periarticular bupivacaine injections alone are as effective as adductor canal blocks, or 
combined adductor canal blocks and periarticular bupivacaine injections, for post-operative pain control following TKA. 
We hypothesize that standard periarticular bupivacaine injections will be as effective as adductor canal blocks for post-operative 
pain management following TKA.  The primary outcome in this study will be pain scores in the immediate post-operative period 
(post-operative day 0 through post-operative day 3).  Secondary outcomes include post-operative narcotic use, length of stay, 
range of knee flexion, and activity level.   Results from this study will help determine the most appropriate regional pain 
management strategy for patients undergoing a TKA. 
 
2. Research Strategy 
Significance 
Over 600,000 total knee arthroplasties (TKAs) are performed each year in the United States, with expectations for greater than 4 
million/year by the year 2030.7  Since the onset of TKAs in the 1960’s, there have been developments that have improved both 
functionality and patient satisfaction.  In the last decade, a focus has been made on multimodal pain management protocols, more 
rapid functional recovery, reduced length of hospital stay, and minimizing side effects of treatment while maintaining function 
and durability.8  The widespread use of regional anesthesia has led to improvements in pain control, more rapid functional 
recovery, and reduced length of stay.1  Femoral nerve blocks have been shown to reduce opioid consumption and decrease post-
operative pain scores.  More recently, surgeons have transitioned to adductor canal blocks (distal femoral nerve) to  maintain a 
sensory block for pain control, while minimizing any motor blockade that is typically seen in proximal femoral nerve blocks, 
which would hamper rehabilitation, and increase risk of falls.2  However, even with a more distal femoral nerve block, the risk of 
motor involvement is still present.   
Due to this potential risk, some surgeons prefer a less invasive regional pain management strategy, such as a periarticular 
anesthetic injection (PAI).  Unlike nerve blocks, which are typically performed by the anesthesia team in the preoperative setting, 
PAIs are administered intraoperatively, usually just prior to closure.  In theory, PAI has the advantage of a comparable sensory 
block as an adductor canal block, without the disadvantages and risks, which include prolonged quadriceps weakness, fall risk, 
and neurologic dysfunction.3   PAIs are typically performed with bupivacaine.  In addition, some surgeons administer a PAI in 
conjunction with an adductor canal block, preferring a multi-modal regional pain management strategy.  However, whether the 
combined strategy enhances pain control is not proven. 
This study will elucidate the differences in pain control between adductor canal blocks and PAI with bupivacaine. These results 
will have an immediate and meaningful clinical impact on perioperative management in TKA.  In addition to increased patient 
satisfaction through optimized post-operative pain control, this study has the potential to lead to cost-savings through the 
elimination of less effective treatment strategies and decrease in hospital length of stay.  Due to the prevalence of TKA, this will 
affect millions of people over the next few years, and has the potential for major cost-savings.   
 
Innovation 
To date, no published studies have compared adductor canal block versus PAI in TKA.  This will be the first study to compare 
these two treatment modalities, and, therefore, has the potential to change perioperative treatment algorithms in TKA.   
Approach 

Study Design: 
This study will be a randomized control trial.  There will be 3 study groups: 
1) Adductor canal block alone (ACB) 
2) Periarticular Standard Bupivicaine alone (SB) 
3) Adductor canal block + Periarticular Standard Bupivicaine (ACB+SB) 
There will be 50 patients in each study group, for a total of 150 enrolled patients.  The study population will be 150 consecutive 
patients undergoing a unilateral primary total knee arthroplasty under the care of the two senior arthroplasty surgeons at this 
institution. Patients will be enrolled pre-operatively at the pre-operative clinic visit, and randomized at that time to one of the five 
groups.  As is standard of care, the adductor canal blocks (15 cc’s of 0.5% bupivacaine) will be performed by the regional pain 
anesthesia team in the pre-operative block area, just prior to surgery.  As is standard of care, the periarticular injections (50 cc’s 
of bupivacaine) will be performed intraoperatively, prior to wound closure, by the performing surgeon.  Floor staff and therapists 
will be blinded to the treatment group.  Patients will be blinded to the intraoperative medication (SB versus LB), but not the pre-
operative block.  Neither the surgeon nor surgical team (including anesthesiology) will be blinded to the treatment group.   
Post-operatively, visual analog scale (VAS) pain scores will be recorded two times/day from POD0 through POD3.  This will be 
the primary outcome. Secondary outcomes monitored in the immediate post-operative period will include: 
Activity level: Steps taken in daily physical therapy sessions will be recorded. 
Opioid consumption:  All patients will have the same opioid pain medications offered on an as needed basis.  The amount of 
opioid consumption will be recorded.  In addition, all patients will receive toradol, and then celecoxib as part of the standard of 
care multi-modal pain management for TKAs at this institution. 
Range of knee flexion: Range of knee flexion, for both passive and active motion, will be recorded prior to discharge, and at 3 
week follow-up for all groups. 
Length of stay:  Total length of hospital stay from time of surgery through time of discharge will be recorded.  In addition, 
location of discharge (home versus rehabilitation center), will be recorded. 
Inclusion Criteria 
All patients undergoing a unilateral primary total knee arthroplasty under the care of the two senior arthroplasty surgeons.   
Potential Difficulties and Limitations 
A large randomized clinical trial creates the potential for coordination issues.  The study locations include the preoperative area, 
operating room, inpatient floor, and outpatient office.  In order to ensure seamless coordination between study staff and the care 
team, we will have a designated study coordinator.  The study coordinator will ensure that study execution and data collection 
with appropriate timing and location.  Any issues that arise at the beginning the study, will be addressed immediately by 
coordinating frequent research team meetings. 
Statistical Procedures: 
 
A power analysis reveals that 50 patients per group will be adequately powered to identify a VAS difference of 0.5 between 
groups, with β=0.8.  VAS pain scores and continuous measures will be compared with unpaired student t-tests.  Narcotic 
equivalents will be compared with a Mann-Whitney U test.  Statistical significance will be defined as p<0.05. 
 
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