Femoral Triangle and Adductor Canal Blocks Versus Femoral Nerve Block for Total Knee Arthroplasty: Postoperative Pain Management and Functional Recovery
Phase: NA
Conditions: Total Knee Arthroplasty
Sponsor: Lithuanian University of Health Sciences

Femoral Triangle and Adductor Canal Blocks Versus 
Femoral Nerve Block for Total Knee Arthroplasty 
 
NCT03645954 
 
August 24, 2018 
 
Study Protocol 
 
Aim of the study: to evaluate and compare the femoral triangle and adductor canal 
blocks and the femoral nerve block regarding the, extent of motor blockade, 
postoperative analgesic efficacy, ability of early ambulation in patients following 
primary total knee arthroplasty. 
Objectives:  
1. To assess and compare the extent of motor blockade after the surgery between 
the femoral triangle and adductor canal blocks group and the femoral nerve 
block group after the primary total knee arthroplasty. 
2. To compare postoperative pain control effects between the femoral triangle 
and adductor canal blocks group and the femoral nerve block group after the 
primary total knee arthroplasty. 
3. To estimate the need for additional opioid analgesics and their adverse effects 
in the femoral triangle and adductor canal blocks and the femoral nerve block 
groups of patients after primary total knee arthroplasty. 
4. To compare patients postoperative satisfaction rates between the femoral 
triangle and adductor canal blocks group and the femoral nerve block group 
after the primary total knee arthroplasty. 
Design and Methods:  
The 
prospective, 
double-blinded 
study 
includes 
American 
Society 
of 
Anesthesiologists (ASA) physical status I-III in preoperative assessment, aged 18-
90 years, scheduled for primary total knee replacement surgery. Preoperatively 
patients will be blindly randomized into one of two groups: the femoral triangle and 

adductor canal blocks group and the femoral nerve block group. Group assignment 
will be concealed by opaque envelopes that will be opened only after the patients 
enrollment. The anesthesiologist who will perform the block will be aware of the 
treatment, but the participant and outcomes assessor will be blinded to the group 
assignment. All blocks will be performed by the anesthesiologist under the 
ultrasound guidance. The femoral nerve block will be performed with 20 mL of 
0.125% bupivacaine injection. The femoral triangle and adductor canal blocks will 
be performed together with injection of 10 mL of 0.125% bupivacaine for each 
block. During the perioperative period all patients will receive premedication of 
midazolam 2.5-5 mg and dexamethasone 4 mg. A slow fluid infusion of crystalloids 
with 1 g of tranexamic acid and 10 mg of ketamine will be started once as an 
intravenous cannula will be placed. Spinal anesthesia after identification of the 
subarachnoid space will be performed with 15 mg of levobupivacaine. After that, 
one of the peripheral nerve blocks will be performed. During surgery patients will 
be sedated with intravenous propofol. The local infiltration analgesia will be 
performed by the surgeon at the end of surgery with combination of 30 mL of 0.5% 
bupivacaine, 0.3 mL of 0.1% adrenaline and 90 mL of 0.9% sodium chloride. After 
the surgery patients will be transferred to the post-anesthesia care unit (PACU). 
After the surgery for analgesia NSAIDs will be available to both groups of patients. 
NSAIDs such as dexketoprofen 50 mg will be administered 2 times and 
acetaminophen 1 g will be administered 3 times per day. Opioids will also be 
available to patients as intramuscular boluses of pethidine 50 mg or morphine 10 mg 
without restriction and administered for moderate or severe pain. The extent of 
motor blockade will be evaluated at 3, 6, 24, 48 hours after surgery. Patients will be 
asked to flex the foot, to flex the knee and to lift up the straight leg. The possible leg 
motion at 3, 6, 24 and 48 hours postoperatively will be assessed with Bromage scale 
grades. Postoperative pain control efficacy will be assessed at 3, 6, 24 and 48 hours 
after surgery using visual analogue scale (VAS) from 0 to 10 (0 - no pain, 10 - worst 
imaginable pain) at rest, during active and passive 45 degree knee flexion. The 
requirement of additional analgesics and their adverse effects will be recorded. 

Patients ability of early ambulation will be evaluated using Timed Up and Go (TUG) 
test at 24 and 48 hours after surgery. To do the TUG test, patients will have to sit 
down on the bed, get up from the bed, walk 3 meters forward, turn, walk back 3 
meters to the bed and sit down. The time taken by a patient to perform this test will 
be calculated with a chronometer. After the conversation with each patient and 
assessment of postoperative pain control efficacy, extent of motor blockade, ability 
of early ambulation, the rate of patient satisfaction will be evaluated using a 10 point 
scale from 0 to 10 at 3, 6, 24, 48 hours after surgery. The rate of complications (if 
any), including falls, local anesthetic toxicity or neurological complications, will be 
recorded in both groups of patients. According to study protocol, both groups of 
patients will be compared in terms of the extent of motor blockade postoperative 
pain control, ability of early ambulation, need for additional opioid analgesics, 
satisfaction rates over the time of clinical recovery. 
 
 
 

Statistical Analysis Plan 
The age, gender, BMI, ASA status will be collected. 
The variable for power calculation analysis is the difference in motor blockade 
between the groups of patients. The difference in motor blockade of 30% would be 
clinically significant. To detect differences for a power of 90% and a 2-tailed α error 
of 0.05, a sample size of 33 patients per group would be required. However, due to 
possible missing data, 80 patients will be included in the study. 
The statistical analysis will be performed using SPSS (version 25.0 IBM). The 
Kolmogorov-Smirnov test will be used to assess the normality of data distribution. 
For normally distributed numerical variables the Student t test will be used to 
compare means. Categorical variables will be compared using the Chi-squared test. 
A p value < 0.05 will be chosen as statistically significant.