"The Effect of Adductor Canal Block Performed With Postoperative Thigh Tourniquet Application on Pain After Total Knee Arthroplasty"
Phase: NA
Conditions: Total Knee Arthroplasty for Gonarthrosis
Sponsor: Ankara Etlik City Hospital

COVER PAGE   
Official Title: The Effect of Tourniquet Application on Analgesic Efficacy and Local Anesthetic Spread 
Pattern During Adductor Canal Block After Total Knee Arthroplasty: A Prospective Observational 
Study   
• NCT Number: Not yet assigned •  
 Document Date: March 25, 2026  
 STUDY PROTOCOL & STATISTICAL ANALYSIS PLAN  
 1. Background and Objectives :  
 The primary aim of this study is to evaluate whether a short-term tourniquet application during an 
Adductor Canal Block (ACB) modifies the distribution of local anesthetics. We hypothesize that the 
tourniquet acts as a mechanical barrier, preventing proximal spread toward the femoral nerve 
while facilitating distal redirection toward the popliteal region via the adductor hiatus to improve 
posterior knee analgesia.  
 2. Study Design:  
This is a prospective, observational, comparative clinical study conducted at 
Ankara Etlik Şehir Hastanesi Participants undergoing elective unilateral total knee arthroplasty are 
enrolled.  
 3. Intervention (The Tourniquet-Assisted ACB Technique):   
Ultrasound Guidance: Procedures are performed using a GE LOGIQ™ system with a 6–15 MHz linear 
probe.   
Procedure: Following surgery, patients receive an ACB. In the Study Group, a pneumatic tourniquet is 
applied to the proximal thigh (pressurized to 19–27 kPa). Initially, 20 mL of local anesthetic (0.25% 
Bupivacaine) is injected while the tourniquet is inflated to create a mechanical barrier. After 3–5 
minutes, the tourniquet is released, and an additional 20 mL of the same solution is administered 
(Total: 40 mL).   
The Control Group receives a standard single-injection ACB of 20 mL (0.25% Bupivacaine) without any 
tourniquet application. Real-time Monitoring: Local anesthetic spread is monitored dynamically via 
ultrasound to detect any proximal escape to the femoral nerve sheath.  
 4. Primary and Secondary Outcomes  
 Primary Outcome: Visual Analog Scale (VAS) scores at 3, 8, 12, and 24 hours postoperatively (both at 
rest and during movement).   
Secondary Outcomes: Total opioid consumption within the first 24 hours (specifically Tramadol 
hydrochloride [Contramal]), presence of motor block (assessed by quadriceps muscle strength), and 
the dynamic pattern of local anesthetic spread (proximal vs. distal) monitored via ultrasound.  
 5. Statistical Analysis Plan (SAP) Sample Size: The sample size was determined to achieve a statistical 
power of 95% based on previous literature regarding VAS score reductions.   
Data Analysis: Statistical analysis will be performed using SPSS software. Continuous variables will be 
expressed as mean ± standard deviation or median (interquartile range). Tests: Normality will be 
assessed using the Shapiro-Wilk test. Independent samples ttest or Mann-Whitney U test will be used 

for group comparisons. Repeated measures ANOVA or Friedman test will be used for temporal pain 
score analysis. Significance: A p-value of < 0.05 will be considered statistically significant.