Effect of Intravenously Administered Tranexamic Acid on Intraoperative Visual Clarity, Perioperative Blood Loss and Early Postoperative Outcomes in Shoulder Arthroscopy Performed in the Beach Chair Position: A Randomized Controlled Trial
Phase: PHASE4
Conditions: Rotator Cuff Tears, Hemorrhage, Surgical, Shoulder Injuries
Sponsor: Nikola Matejcic

STUDY PROTOCOL AND STATISTICAL ANALYSIS PLAN 
 
 
 
Official Title: 
Effect of Intravenously Administered Tranexamic Acid on Intraoperative Visual 
Clarity, Perioperative Blood Loss, and Early Postoperative Outcomes in 
Shoulder Arthroscopy Performed in the Beach Chair Position: A Randomized 
Controlled Trial 
 
NCT Number: 
NCT05397652 
 
Document Date: 
22 December 2025 
 
 
 
 
 
 
 
 
 
 

1. Background and Rationale 
Adequate intraoperative visual clarity is essential for safe and effective 
shoulder arthroscopy. Visualization quality depends largely on the amount of 
bleeding into the irrigation fluid and cannot be supported by tourniquet use, 
unlike arthroscopy of the extremities. Strategies to optimize visualization 
therefore include hypotensive anesthesia, modulation of irrigation pressure, 
meticulous hemostasis, and pharmacological interventions. 
Tranexamic acid (TXA) is a synthetic antifibrinolytic agent that reduces blood 
loss by inhibiting plasminogen activation. It is widely used in orthopedic 
surgery and has demonstrated a favorable safety profile. However, evidence 
regarding its effect on intraoperative visual clarity during shoulder arthroscopy 
is limited and heterogeneous. Previous studies often relied solely on subjective 
assessment of visibility and rarely incorporated objective measures of 
intraoperative bleeding. 
This prospective randomized controlled trial was designed to evaluate the 
effect of intravenously administered TXA on intraoperative arthroscopic 
visibility during shoulder arthroscopy performed in the beach chair position. 
Subjective assessments of visual clarity were supplemented with objective 
measurements of hemoglobin concentration in irrigation fluid and 
independent postoperative evaluation of intraoperative images by blinded 
expert assessors. 
 
2. Objectives 
Primary Objective 
To assess the effect of intravenously administered tranexamic acid on 
intraoperative arthroscopic visual clarity during shoulder arthroscopy. 
Secondary Objectives 
• To evaluate interobserver agreement among independent assessors of 
arthroscopic visibility. 
• To compare arthroscopic visibility ratings between the operating 
surgeon and independent assessors. 

• To assess objective indicators related to visibility, including hemoglobin 
concentration in irrigation fluid, irrigation pressure adjustments, 
irrigation fluid volume, and mean arterial pressure. 
• To assess intraoperative and perioperative blood loss parameters. 
• To evaluate early postoperative recovery outcomes, including swelling, 
pain, analgesic consumption, and length of hospital stay. 
 
3. Study Design 
This was a prospective, single-center, double-blind, randomized controlled 
clinical trial conducted at the University Orthopaedic and Trauma Hospital 
Lovran, Croatia. 
 
4. Participants 
Inclusion Criteria 
• Adults aged 18–65 years 
• Indication for therapeutic shoulder arthroscopy with rotator cuff repair 
Exclusion Criteria 
• Known hypersensitivity to tranexamic acid 
• History of venous or arterial thromboembolism 
• Known coagulation disorders or thrombophilia 
• Renal insufficiency 
• Recent cerebrovascular or coronary events 
• Chronic anticoagulant or antiplatelet therapy 
• Uncontrolled arterial hypertension 
 
5. Interventions 
Experimental Group 
Participants received 1 g of tranexamic acid diluted in 100 mL of sterile saline 
administered intravenously 10 minutes before the start of surgery. 

Control Group 
Participants received 100 mL of sterile saline administered intravenously using 
identical, non-specific packaging. 
 
6. Randomization and Blinding 
Participants were stratified by age and sex and randomized using simple 
randomization within strata. Allocation was performed by a research 
collaborator not involved in patient care or outcome assessment. Patients, 
surgeons, anesthesiology staff, physiotherapists, and outcome assessors were 
blinded to treatment allocation throughout the study. 
 
7. Surgical Procedure and Perioperative Management 
All procedures were performed in the beach chair position by the same 
surgeon using standardized arthroscopic equipment. A 4-mm 30° arthroscope 
was used. The arthroscopic pump was set to a baseline pressure of 50 mmHg, 
with temporary increases of 20 mmHg permitted for up to 2 minutes as 
needed. No adrenaline or tranexamic acid was added to the irrigation fluid. 
 
8. Outcome Measures 
Primary Outcome Measure 
• Intraoperative arthroscopic visibility (VAS) rated by the operating 
surgeon every 15 minutes from skin incision to the end of the procedure. 
Secondary Outcome Measures 
• Postoperative VAS ratings of intraoperative images by three 
independent blinded expert assessors. 
• Interobserver agreement among independent assessors for VAS 
ratings. 
• Comparison of VAS ratings between the operating surgeon and 
independent assessors. 

• Hemoglobin concentration in irrigation fluid as an objective indicator of 
intraoperative bleeding. 
• Number of irrigation pump pressure-boost events. 
• Total irrigation fluid volume used. 
• Intraoperative mean arterial pressure (MAP). 
• Duration of surgery. 
• Intraoperative blood loss. 
• Total perioperative blood loss. 
• Postoperative (hidden) blood loss. 
• Perioperative hemoglobin decrease. 
• Upper-arm circumference as a marker of postoperative swelling. 
• Postoperative pain intensity (VAS). 
• Total postoperative analgesic consumption. 
• Length of hospital stay. 
 
9. Data Collection Procedures 
At the beginning of surgery and every 15 minutes thereafter, the operating 
surgeon assessed arthroscopic visibility using the VAS-V scale (0–10). At the 
same time points, standardized photographs of the arthroscopic monitor were 
obtained and stored. 
After completion of surgery, intraoperative images were independently 
evaluated by three experienced arthroscopic surgeons blinded to treatment 
allocation using the same VAS-V scale. 
Irrigation waste fluid was collected, homogenized, and sampled for 
spectrophotometric determination of hemoglobin concentration. 
Intraoperative data included operative time, mean arterial pressure, number 
of irrigation pressure increases, and total irrigation fluid inflow and outflow 
volumes. All procedures, implants, and intraoperative technical issues were 
documented. 
Postoperative assessments included shoulder circumference measurements, 
pain intensity scoring, analgesic consumption, venous blood sampling for 
complete blood count analysis, and length of hospital stay. 
 
 

10. Statistical Analysis Plan 
Descriptive statistics were used to summarize baseline characteristics and 
outcome measures. Normality of distribution was assessed using the Shapiro–
Wilk test. Between-group comparisons were performed using independent 
samples t-tests or non-parametric equivalents as appropriate. Repeated 
intraoperative measurements were summarized per participant. Interobserver 
agreement among independent assessors was evaluated using reliability 
statistics. Correlations were assessed using appropriate correlation 
coefficients. Statistical significance was set at p < 0.05. 
 
11. Ethical Considerations 
The study was conducted in accordance with the Declaration of Helsinki and 
approved by the relevant institutional ethics committee. Written informed 
consent was obtained from all participants. The trial was registered at 
ClinicalTrials.gov.