Clinical trial NCT03353233
Conditions: Knee Osteoarthritis Primary Total Knee Arthroplasty Physical Therapy Pain Knee Extension
Keywords: iPACK Interspace between the Popliteal Artery and Capsule of the Knee Posterior Capsule block Nerve Block
Sponsor: Duke University
Start date: 2018-05-03; Completion date: 2021-01-23
Enrollment: 50 participants; Allocation: RANDOMIZED; Intervention model: PARALLEL

Brief summary:
The purpose of this study is to learn if using an Interspace between the Popliteal Artery and Capsule of the Knee (iPACK) injection technique (also called a "nerve block") that numbs the nerves going to the back part of the knee to aid in physical therapy after surgery. The iPACK technique uses a numbing solution (local anesthetics) that is injected behind the knee to reduce pain and to help straighten the knee. This block may affect movement in the leg and make the legs weak, but thing is rare. A few institutions use the iPACK block for patients having total knee replacements, with the hope of providing good pain relief combined with improved mobility after surgery.

Detailed description:

Arms: arm 1: A nerve block technique using a numbing medication called ropivacaine. arm 2: The same nerve block technique as above, however using an inactive solution of salt water.
Interventions: intervention 1: Ropivacaine intervention 2: Interspace Between the Popliteal Artery and Capsule of the Knee (iPACK) Block intervention 3: Saline
Intervention descriptions: intervention 1: Local anesthetic (numbing drug) intervention 2: An ultrasound guided nerve block using a numbing medication called ropivacaine that numbs the nerves to the back of the knee. intervention 3: An ultrasound guided nerve block using a medication that does NOT numb the nerve called saline, or salt water.

Protocol documents:
Prot_SAP_000.pdf: 
 
 
 
 
 
 
 
 
 
 
 
Evaluation of utility of ultrasound guided iPACK block for knee extension after total knee arthroplasty 
 
Document Date: January 6, 2021 
 
NCT03353233 
 
 


Purpose of the Study 
  
This prospective double-blind study aims to evaluate the functional benefit of the interspace 
between the popliteal artery and the capsule of the knee (iPACK) block for postoperative physical 
therapy (PT) following total knee arthroplasty (TKA).  English speaking ASA 1-3 patients ages 18-75 years 
old undergoing primary TKA will be randomized into 2 groups, one receiving 20mL 0.2% ropivacaine with 
1:400,000K epinephrine as part of our standard TKA protocol and the other group 20 mL 0.9% saline. 
The primary outcome will be difference in knee extension within the first 8 hours after surgery as 
evaluated by our physical therapists. Secondary outcomes include numerical pain scores and opioid 
consumption over 24 hours, other PT measures, and hospital length of stay. Participants will assume 
standard risk associated with nerve blocks, including theoretical risk of nerve damage and local 
anesthetic systemic toxicity. 
 
Background & Significance 
 
Postoperative pain following total knee arthroplasty (TKA) continues to persist despite a wide 
variety of methods available for analgesia.  The knee joint receives innervation from the 3 major nerves 
of the lower extremity, the femoral, obturator, and sciatic nerves.  Current practices incorporate 
femoral nerve blockade as part of the analgesic regimen for the anterior skin and within the joint itself1.  
The posterior knee receives branches from the tibial and common peroneal nerves. 
           The ideal analgesic regimen would provide adequate analgesia with minimal effect on motor 
function. Currently, analgesic regimens for TKA include regional anesthesia for components of femoral 
and sciatic nerves.  Achieving complete analgesia by blocking the femoral and sciatic nerves would 
provide excellent analgesia, however would not allow the patient to participate in PT and may delay 
discharge.  Likewise, pain after TKA not only causes patient dissatisfaction, but can limit postoperative 
rehabilitation, prolong hospital discharge, increase opioid consumption, and increase cost. 
            A recent randomized-controlled trial has demonstrated that sciatic nerve blocks reduce pain 
compared with placebo2.  In addition to pain control, sciatic nerve blockade also inhibits motor fibers, 
which limit participation in rehabilitation. In order to decrease motor blockade, Sinha and colleagues 
described a field block in the interspace between the popliteal artery and capsule of the knee (iPACK)3.  
This technique anesthetizes the nerves supplying the posterior part of the knee, specifically the 
posterior articular nerve and geniculate nerves. This block become part of our comprehensive 
multimodal analgesic regimen for TKA.  While some research has shown not shown efficacy from the 
iPACK block4, emerging data has shown benefit including improved participation in PT and decrease 
time to discharge5,6. No current studies, however, have been performed utilizing our comprehensive 
analgesic protocol, including multimodal analgesia, adductor canal catheter, and iPACK single shot block 
to show improvement in post-operative PT outcomes, specifically knee extension.  Proper knee 
extension is a key component in acute post-operative rehabilitation, allowing the patient to fully 
participate in PT.  Participation in PT improves both long- and short-term outcomes, including 
ambulation and knee flexion and extension7-9.  The goal of this prospective double-blind study aims to 
evaluate the benefit of the iPACK block as part of a comprehensive perioperative analgesic pathway for 
TKA in order to evaluate its effects on PT outcomes.  The main outcome our study will address is knee 
hyperextension.   
 


Design & Procedures 
 
ASA 1-3 patients aged 18-75 years old undergoing primary TKA will be enrolled. Patients will be 
identified preoperatively and contacted by telephone by primary investigator (WMB) or study 
personnel.  The study will be explained in full detail, after which patients will be given the opportunity to 
ask questions about the study.  If patients are interested in participating, they will be again explained 
the protocol and informed consent will be obtained the day of surgery. 
           Patients will be given the standard of care at Duke University Hospital per our TKA protocol with 
the exception of the study intervention.  Preoperatively, patients will be given 975mg acetaminophen 
and 300mg gabapentin by mouth prior to surgery.  These medications may be altered or not given 
depending on patient comorbidities or other extenuating factors such as allergy/intolerance.  
Furthermore, a spinal anesthetic will be placed in the preoperative area followed by the iPACK 
intervention. 
Patients will be randomized to either iPACK block group or sham group. Prior to patient 
enrollment, group allocations will be determined by an online randomization program used by the study 
PI (WMB). To ensure blinding, randomizations will be sealed in envelopes numbered 1-50. Upon 
enrollment, patients will be given a number (1-52) and the corresponding envelope will be given to a key 
unblinded study personnel member (JG), who will not be involved in the iPACK intervention nor in post-
operative analysis. This key member will supply the regional anesthesiologist performing the 
intervention with the study drug -- either 30mL 0.2% ropivacaine or sham block, consisting of 30mL 
saline. Both the regional anesthesiologist performing the intervention and the patient will be blind as to 
the contents of the syringe. 
Following the intervention, patients will be taken to the operating room and sedated using IV 
propofol to a bispectral index (BIS) of 60-80, indicating adequate sedation. Once sedated, patients will 
be given a 0.5mg/kg ketamine bolus (based on ideal body weight) and 10mg dexamethasone will be 
given prior to incision. The orthopedic surgery attending will determine the degree of preoperative knee 
extension prior to the procedure and inform the anesthesia team. At conclusion of the case sedation will 
be stopped and patient will be taken to the post-operative care unit (PACU). 
Post-operatively, patients will be assessed on arrival to determine level of pain as well as 
nausea/vomiting and for return of sensation. Prior to return of sensation, an adductor canal catheter 
will be placed as part of the TKA protocol. In addition to catheter placement, patients will have post-
operative orders for pain control that include 0.2mg IV hydromorphone for pain scores 5-7 and 0.4mg IV 
hydromorphone for pain scores 8-10. If patient has pain, site of pain will be determined, specifically 
inquiring about posterior knee pain. Finally, per the protocol, a one-time dose of 15mg IV ketorolac will 
be given prior to discharge from PACU. 
Range of motion, specifically knee extension, will be measured with a goniometer in the first PT 
evaluation within the first 8 hours after surgery. Additional measures include knee flexion, distance 
ambulated, and timed-up-and-go (TUG) test. Furthermore, pain scores and cumulative opioid 
administration (in IV morphine equivalents) will be recorded for the first 4 hours, at 8 hours, and at 24 
hours following surgery. Complications and hospital length of stay will also be recorded. 
Selection of Subjects 
  
 
 


Inclusion Criteria: 
            Patients that will be included in the study are English speaking 18-75 year old ASA 1-3 patients 
undergoing primary total knee arthroplasty. 
  
Exclusion Criteria: 
            Patients will be excluded from the study if they meet one or more of the following  
            1) ASA 4 or 5 
            2) Revision knee arthroplasty 
            3) Diagnosis of chronic pain 
            4) Daily chronic opioid use (over 3 months of continuous opioid use). 
            5) Inability to communicate pain scores or need for analgesia. 
            6) Infection at the site of block placement 
            7) Age under 18 years old or greater than 75 years old 
            8)Pregnant women (as determined by point-of-care serum bHCG) 
            9) Intolerance/allergy to local anesthetics 
10) Weight <50 kg 
11) Suspected, or known addiction to or abuse of illicit drug(s), prescription medicine(s), or alcohol 
within the past 2 years. 
12) Uncontrolled anxiety, schizophrenia, or other psychiatric disorder that, in the opinion of the 
investigator, may interfere with study assessments or compliance. 
13) Current or historical evidence of any clinically significant disease or condition that, in the opinion of 
the investigator, may increase the risk of surgery or complicate the subject’s postoperative course. 
  
Risk/Benefit Assessment 
 
Patients will not incur any added risk to standard risks incurred with both general and regional 
anesthesia.  These standards risks are: 
Regional anesthesia - minor pain or discomfort, injury to arteries, veins or nerves affecting the arms or 
legs, residual numbness or weakness or paralysis, headache, muscle soreness, infection, allergy or 
adverse drug reaction, intravascular injection of local anesthetic causing seizure or cardiac arrest. 
            Patients will be monitored in the post-operative care unit by nurses assigned to their care.  
Patients will have analgesic medications available for pain if needed including 0.2mg hydromorphone for 
pain score 5-7/10 and 0.4mg hydromorphone for pain scores 8-10/10.  These medications will be given 
every 8 minutes as needed based on pain score. 
            Benefits include contributing to general knowledge base to improve future patient care.  This 
includes potential confirmation of better range of motion postoperatively, increased participation in PT, 
analgesic benefit, decreased pain scores, and improved patient satisfaction.  Conversely, this study may 
show no benefit of the block, thereby changing patient care by decreasing amount of total local 
anesthetic given, fewer needle punctures, and decreased cost. 
 
Data Analysis & Statistical Considerations 
 
A double blinded randomized (1:1) trial assuming a rate of hyperextension of 20% in the placebo 
group, will provide 91% power to detect a 50% increase in the rate of hyperextension in the treatment 


group in a chi-square test at alpha level 0.05. Sample size and power calculations were performed using 
PASS v15 (NCSS, LLC. Kaysville, Utah). 
            Patient and surgical characteristics will be summarized by standard descriptive statistics and will 
be compared between groups using t-tests, Wilcoxon rank sum tests, chi-square tests, or Fisher exact 
tests as appropriate. A chi-square test and logistic regression models will be used to assess the effect of 
treatment on rate of hyperextension. We will report odds ratios, 95% confidence intervals, and p-values 
to assess significance and clinical importance of the observed treatment effect.  Additional measures of 
treatment efficacy (range of motion, pain scores, and opioid consumption) will be summarized overall 
and between groups to further characterize the treatment effect in this population.  Randomization 
schedules will be prepared using mixed block sizes in nQuery and significance will be set at 0.05 for all 
analyses. 
 
Data & Safety Monitoring 
 
In accordance with federal regulations the PI will monitor for, review, and promptly report to 
the IRB, appropriate institutional officials, sponsor, coordinating center and the appropriate regulatory 
agency head all unanticipated problems involving risks to subjects or others that occur in the course of a 
subject’s participation in a research study (45 CFR 46.103(b)(5)(i) and 21 CFR 56.108(b)(1)), all AE reports 
will be reported per the DUHS IRB policies. PI will be monitoring all AEs and submitting reports to the 
IRB per DUHS IRB policy. 

ICF_001.pdf: 
Consent To Participate In A Research Study
Evaluation of utility of ultrasound guided posterior capsule 
block for posterior knee pain after total knee arthroplasty.
Page 1 of 6                                                  Subject*Initials:______________
DUKE UNIVERSITY HEALTH SYSTEM
Form
M0345
CONCISE SUMMARY
The purpose of this study is to determine the effectiveness of a nerve block, called the iPACK 
(interspace between the popliteal artery and capsule of the knee) block, on physical therapy after 
surgery. The information we can gain from this study may help us improve our future knee replacement 
patients’ abilities to participate in physical therapy, which can improve long-term recovery after surgery.
Participants in this study will undergo the iPACK block with numbing medicine or placebo (inactive 
agent) prior to surgery. Per our usual protocol for knee replacements, a physical therapist will evaluate 
your knee within 8 hours after surgery. You will be enrolled in our study for 24 hours after surgery.
If you agree to take part in this study, there may be direct medical benefits to you. If you receive the
iPACK block with the numbing medicine, you may experience better movement in your knee while in 
the recovery room. However, this cannot be guaranteed. If you receive placebo, there is not expected to 
be a benefit above standard of care.
The risks of this study are mainly due to the iPACK intervention.  This includes minor pain or 
discomfort, injury to arteries, veins or nerves affecting the limbs, residual numbness or weakness or 
paralysis, headache, muscle soreness, infection, allergy or adverse drug reaction, intravascular injection 
of local anesthetic causing seizure or cardiac arrest.
You are being asked to take part in this research study because you are having total knee replacement 
surgery. As part of the pain control for this surgery, you would be getting a nerve block called an 
iPACK (interspace between the popliteal artery and capsule of the knee) block, also known as a 
posterior capsule block to help control the pain in the back of your knee. This study is being funded by 
the Department of Anesthesiology at Duke University Medical Center.
Research studies are voluntary and include only people who choose to take part. Please read this consent 
form carefully and take your time making your decision. As your study doctor or study staff discusses 
this consent form with you, please ask him/her to explain any words or information that you do not 
clearly understand. We encourage you to talk with your family and friends before you decide to take part 
in this research study. The nature of the study, risks, inconveniences, discomforts, and other important 
information about the study are listed below.
Please tell the study doctor or study staff if you are taking part in another research study.
WHO WILL BE MY DOCTOR ON THIS STUDY?
If you decide to participate, Dr. William (Michael) Bullock will be your doctor for the study and will be 
in contact with your regular health care provider throughout the time that you are in the study and 
afterwards, if needed.
DUHS IRB
IRB NUMBER: Pro00070573
IRB REFERENCE DATE: 01/06/2021
IRB EXPIRATION DATE: 01/04/2022


Consent To Participate In A Research Study
Evaluation of utility of ultrasound guided posterior capsule 
block for posterior knee pain after total knee arthroplasty.
Page 2 of 6                                                  Subject*Initials:______________
DUKE UNIVERSITY HEALTH SYSTEM
Form
M0345
WHY IS THIS STUDY BEING DONE?
The purpose of this study is to learn if using a nerve block, the iPACK block that numbs the small 
nerves going to the back of the knee, makes it easier to straighten your leg (extend your knee) after your 
surgery. This block will not affect the way you move your knee and will last about 10-12 hours.  Many 
hospitals, including Duke, use the iPACK block for patients having knee replacements hoping to provide 
better pain relief and better motion after surgery. 
For knee replacement surgery at Duke University Hospital, it is typical to numb up different nerves in 
your leg to help control pain after surgery in both front and back.  The front part is numbed by an 
adductor canal block, which includes the use of numbing medicine through a tube or catheter.  As a 
result, patients usually will have pain in the back of the knee, which makes it harder to straighten the leg 
during physical therapy. We are trying to see if numbing the nerves going to the back of the knee makes 
better leg straightening easier.  Previous studies show that better leg straightening makes your long-term 
recovery better.  
HOW MANY PEOPLE WILL TAKE PART IN THIS STUDY?
Fifty-two (52) subjects will take part at Duke University Hospital.
WHAT IS INVOLVED IN THE STUDY?
If you agree to be in this study, you will be asked to sign and date this consent form. If you do not sign
this consent form, you will continue to receive your regular care, but not as a part of this study.  
As part of your anesthesia care, you will get an iPACK block in the preoperative block area.  For this 
study, you will be randomized to one of two different groups.  "Randomized" means that, like the flip of 
a coin, will be put into one of two different groups.  This is done before you get here and neither you nor 
the doctors doing the block will know what group you are in until the end.
Before we begin, you will be placed on a monitor to see your vital signs and receive oxygen.  You will 
also get some intravenous medications for relaxation and pain (midazolam and fentanyl). A spinal 
anesthetic will be placed in the preoperative area to numb your lower body throughout the surgery.  
After the spinal, the iPACK block is placed using an ultrasound machine to help the anesthesiologist 
place the needle in the correct area behind your knee. Once the needle is in the right place, either 
numbing medicine (ropivacaine) or placebo (saline) is injected through the needle and the needle is then 
taken out. 
For the surgery itself, you will be taken back to the operating room where you will be given sedation 
(propofol) through your IV. After your surgery is finished, you will be moved to the recovery room.  
You will then have an adductor canal catheter block procedure to help control pain for a different part of 
your knee.  This is standard of care at Duke.  Also, you will get the same pain medicines you would 
normally get if you were not in the study.  This includes numbing medicine through the adductor canal 
DUHS IRB
IRB NUMBER: Pro00070573
IRB REFERENCE DATE: 01/06/2021
IRB EXPIRATION DATE: 01/04/2022


Consent To Participate In A Research Study
Evaluation of utility of ultrasound guided posterior capsule 
block for posterior knee pain after total knee arthroplasty.
Page 3 of 6                                                  Subject*Initials:______________
DUKE UNIVERSITY HEALTH SYSTEM
Form
M0345
catheter and variety of pain medications through the IV and by mouth in the recovery room and in your 
hospital room.  If your pain is not well controlled, you and your study doctor can discuss the best plan 
for pain control. Within 8 hours of arriving in the recovery room, a physical therapist will evaluate your 
knee, as is usual after knee replacement surgery.
HOW LONG WILL I BE IN THIS STUDY?
You will be in this study for up to 24 hours after your knee replacement surgery. You can choose to stop
participating at any time without penalty or loss of any benefits to which you are entitled. However, if
you decide to stop participating in the study, we encourage you to talk to your doctor first.
WHAT ARE THE RISKS OF THE STUDY?
Risks of this study includes the following:

Regional Anesthesia (iPACK)- minor pain or discomfort, injury to arteries, veins or nerves 
affecting the limbs, residual numbness or weakness or paralysis, headache, muscle soreness, 
infection, allergy or adverse drug reaction, intravascular injection of local anesthetic causing 
seizure or cardiac arrest.
If receiving placebo, you may receive more pain postoperatively.
Female
Being a part of this study while pregnant may expose the unborn child to significant risks, some of 
which may be currently unforeseeable.  Therefore, pregnant women will be excluded from the study.  If 
you are a woman of childbearing potential, a blood pregnancy test will be done (using 1 teaspoon of 
blood drawn from a vein by needle-stick), and it must be negative before you can continue in this study.  
Drug and Food Interactions:
For your safety, you must tell the study doctor or nurse about all the prescribed medical foods and drugs,
herbal products, over-the-counter (OTC) drugs, vitamins, natural remedies, and alcohol that you are
taking before you start the study and before starting to take any of these products while you are on the
study.
There may be risks, discomforts, drug interactions or side effects that are not yet known.
ARE THERE BENEFITS TO TAKING PART IN THE STUDY?
If you agree to take part in this study, there may be direct medical benefits to you. If you receive the
iPACK block with the numbing medicine, you may experience better movement in your knee while in 
the recovery room, but it is not known yet whether this will be the case. We hope what we learn from 
this study will benefit other people undergoing knee replacement with iPACK nerve blocks. If you are 
randomized to the placebo group, there is not expected to be any benefit above standard of care. Your 
pain may be increased if you receive placebo.  
DUHS IRB
IRB NUMBER: Pro00070573
IRB REFERENCE DATE: 01/06/2021
IRB EXPIRATION DATE: 01/04/2022


Consent To Participate In A Research Study
Evaluation of utility of ultrasound guided posterior capsule 
block for posterior knee pain after total knee arthroplasty.
Page 4 of 6                                                  Subject*Initials:______________
DUKE UNIVERSITY HEALTH SYSTEM
Form
M0345
ALTERNATIVES TO PARTICIPATION IN THE STUDY
You do not have to participate in this study.  If you do not participate, you will receive the iPACK with 
your anesthesia care, which is part of the usual procedure for patients undergoing Total Knee 
Arthroplasty at Duke.
WILL MY INFORMATION BE KEPT CONFIDENTIAL?
Participation in research involves some loss of privacy. We will do our best to make sure that 
information about you is kept confidential, but we cannot guarantee total confidentiality. Your personal 
information may be viewed by individuals involved in this research and may be seen by people 
including those collaborating, funding, and regulating the study. We will share only the minimum 
necessary information in order to conduct the research. Your personal information may also be given out 
if required by law. 
As part of the study, results of your study-related laboratory tests, x-rays, and procedures may be 
reported to Duke University Department of Anesthesiology and its affiliates. In addition, your records 
may be reviewed in order to meet federal or state regulations. Reviewers may include representatives 
from the Food and Drug Administration, representatives and affiliates of Duke University Department of 
Anesthesiology, the Duke University Health System Institutional Review Board, and others as 
appropriate. If any of these groups review your research record, they may also need to review your 
entire medical record.
As part of this study, you will be asked to have certain procedures performed. Some of these procedures 
would have been done as part of your regular care. The study doctor will use these results both to treat 
you and to complete this research.  These test results will be recorded in your medical record and will be 
reported to the Duke University Department of Anesthesiology. Results of tests and studies done solely 
for this research study and not as part of your regular care will also be included in your medical record.
While the information and data resulting from this study may be presented at scientific meetings or 
published in a scientific journal, your name or other personal information will not be revealed.
Some people or groups who receive your health information might not have to follow the same privacy 
rules. Once your information is shared outside of DUHS, we cannot guarantee that it will remain private. 
If you decide to share private information with anyone not involved in the study, the federal law 
designed to protect your health information privacy may no longer apply to the information you have 
shared.  Other laws may or may not protect sharing of private health information.
WHAT ARE THE COSTS?
You or your insurance provider will be responsible and billed for all costs related to your routine 
medical care, including copayments and deductibles. Routine medical care services are those that you 
would have received for your condition if you were not participating in this research study. Not all 
DUHS IRB
IRB NUMBER: Pro00070573
IRB REFERENCE DATE: 01/06/2021
IRB EXPIRATION DATE: 01/04/2022


Consent To Participate In A Research Study
Evaluation of utility of ultrasound guided posterior capsule 
block for posterior knee pain after total knee arthroplasty.
Page 5 of 6                                                  Subject*Initials:______________
DUKE UNIVERSITY HEALTH SYSTEM
Form
M0345
services are covered by insurance.  Some procedures or scans may require pre-authorization by your 
insurance plan. We will notify you if we learn that a service is not covered by your insurance plan as 
part of the pre-authorization process. If it is not covered, you will be responsible for paying for it.  The 
amount of your out-of-pocket expense will depend on your insurance plan.  For beneficiaries with 
Medicare Advantage Plans, traditional Medicare is billed for the routine cost of a research study.  You 
may have more or higher co-pays than with a Medicare Advantage plan.  Please discuss the costs of the 
study with Dr. Bullock.  At your request, a Financial Counselor in the clinic may provide you with an 
estimate of costs for routine services.
WHAT ABOUT COMPENSATION?
You will not be compensated for your participation in this study.
WHAT ABOUT RESEARCH RELATED INJURIES?
Immediate necessary medical care is available at Duke University Medical Center in the event that you
are injured as a result of your participation in this research study. However, there is no commitment by
Duke University, Duke University Health System, Inc., or your Duke physicians to provide monetary
compensation or free medical care to you in the event of a study-related injury.
For questions about the study or research-related injury, contact Dr. Bullock at 919-681-6437 during
regular business hours, or at 505-715-7000 after hours and on weekends and holidays.
WHAT ABOUT MY RIGHTS TO DECLINE PARTICIPATION OR WITHDRAW FROM THE
STUDY?
You may choose not to be in the study, or, if you agree to be in the study, you may withdraw from the
study at any time. If you withdraw from the study, no new data about you will be collected for study
purposes other than data needed to keep track of your withdrawal.
Your decision not to participate or to withdraw from the study will not involve any penalty or loss of
benefits to which you are entitled, and will not affect your access to health care at Duke. If you do
decide to withdraw, we ask that you contact Dr. Bullock in writing or by telephone (505-715-7000) and
let him know that you are withdrawing from the study. His mailing address is Department of 
Anesthesiology, DUMC 3094, Durham, NC, 27710.
We will tell you about new information that may affect your health, welfare, or willingness to stay in
this study.
A description of this clinical trial will be available on http://www.ClinicalTrials.gov, as required by U.S. 
Law. This Web site will not include information that can identify you. At most, the Web site will 
include a summary of the results. You can search this Web site at any time.
DUHS IRB
IRB NUMBER: Pro00070573
IRB REFERENCE DATE: 01/06/2021
IRB EXPIRATION DATE: 01/04/2022


Consent To Participate In A Research Study
Evaluation of utility of ultrasound guided posterior capsule 
block for posterior knee pain after total knee arthroplasty.
Page 6 of 6
                                                  *
DUKE UNIVERSITY HEALTH SYSTEM
Form
M0345
WHOM DO I CALL IF I HAVE QUESTIONS OR PROBLEMS?
For questions about the study or a research-related injury, or if you have problems, concerns, questions
or suggestions about the research, contact Dr. Bullock at 505-715-7000 during regular business hours,
after hours and on weekends and holidays.
For questions about your rights as a research participant, or to discuss problems, concerns or suggestions
related to the research, or to obtain information or offer input about the research, contact the Duke
University Health System Institutional Review Board (IRB) Office at (919) 668-5111.
STATEMENT OF CONSENT
"The purpose of this study, procedures to be followed, risks and benefits have been explained to me. I
have been allowed to ask questions, and my questions have been answered to my satisfaction. I have
been told whom to contact if I have questions, to discuss problems, concerns, or suggestions related to
the research, or to obtain information or offer input about the research. I have read this consent form
and agree to be in this study, with the understanding that I may withdraw at any time. I have been told
that I will be given a signed and dated copy of this consent form."
__________________________________________
 ___________ 
___________
Signature of Subject 
 Date 
Time
__________________________________________ 
 ___________
___________
Signature of Person Obtaining Consent 
 Date 
Time
DUHS IRB
IRB NUMBER: Pro00070573
IRB REFERENCE DATE: 01/06/2021
IRB EXPIRATION DATE: 01/04/2022