The Effect of Platelet-rich Fibrin on the Regeneration of Patellar Ligament Defects and the Functional Recovery of Patients After Anterior Cruciate Ligament Reconstruction of the Knee
Conditions: Anterior Cruciate Ligament Injury, Knee Injuries, Sensory Disorders, Bone-Patellar Tendon-Bone Autograft, Platelet-Rich Fibrin (PRF)
Sponsor: University of Belgrade

Study Protocol Title: Impact of Platelet-Rich Fibrin on Donor Site Regeneration and 
Functional Recovery after ACL Reconstruction with BPTB Autograft 
Version: 01, 18 September 2020 
 
 
COVER PAGE 
Study Protocol Title : Impact of Platelet-Rich Fibrin on Donor Site Regeneration and 
Functional Recovery after ACL Reconstruction with BPTB Autograft 
Version/Date: Version 01, 18 September 2020 
NCT number: Not Available  
 
 
 
 
 
 
 
 
 
 

Study Protocol Title: Impact of Platelet-Rich Fibrin on Donor Site Regeneration and 
Functional Recovery after ACL Reconstruction with BPTB Autograft 
Version: 01, 18 September 2020 
 
 
Study Protocol 
Full Title: Impact of Platelet-Rich Fibrin on Donor Site Regeneration and Functional 
Recovery after ACL Reconstruction with BPTB Autograft 
Protocol ID: 17/VI-3 (Ethics Committee Approval) 
Principal Investigator: Dr. Darko Milovanović, MD 
Institution: University Clinical Center of Serbia / Faculty of Medicine, University of Belgrade 
Version/Date: Version 01, 18 September 2020 
NCT number: Not Available  
 
 
 

Study Protocol Title: Impact of Platelet-Rich Fibrin on Donor Site Regeneration and 
Functional Recovery after ACL Reconstruction with BPTB Autograft 
Version: 01, 18 September 2020 
 
 
1. Background and Rationale 
Anterior cruciate ligament (ACL) injuries are among the most common knee injuries in 
young athletes. Reconstruction using a bone–patellar tendon–bone (BPTB) autograft 
remains a widely accepted technique. However, donor site morbidity, including sensory 
deficits and anterior knee pain, are frequent complications. Platelet-rich fibrin (PRF), an 
autologous biological product, has been suggested to improve wound healing and 
potentially reduce donor site complications. This study was designed to investigate whether 
PRF can reduce sensory deficits and improve functional outcomes after ACL reconstruction 
with BPTB autograft. 
2. Objectives 
Primary Objective: To evaluate the effect of PRF application on sensory disturbances at the 
donor site 12 months after ACL reconstruction. 
Secondary Objectives: To assess MRI healing of the donor site, functional outcome scores 
(IKDC, Lysholm), patient satisfaction, and adverse events. 
3. Study Design 
This is a single-center, prospective, cohort pilot study. Fifty-three patients undergoing ACL 
reconstruction with BPTB autograft were included. Patients were divided into two groups: 
Group 1 (PRF group, n=24) with PRF applied at the donor site, and Group 2 (Control group, 
n=29) with standard closure without PRF. Patients were followed for 12 months 
postoperatively. 
4. Eligibility Criteria 
Inclusion Criteria: 
- Age 18–40 years 
- Isolated ACL rupture confirmed by MRI and clinical examination 
- Planned ACL reconstruction with BPTB autograft 
- Written informed consent provided 
Exclusion Criteria: 
- Previous surgery on the affected knee 
- Associated ligament injuries requiring additional reconstruction 
- Outerbridge grade III–IV cartilage damage outside donor site 
- Systemic diseases interfering with healing (e.g., diabetes, autoimmune disease) 

Study Protocol Title: Impact of Platelet-Rich Fibrin on Donor Site Regeneration and 
Functional Recovery after ACL Reconstruction with BPTB Autograft 
Version: 01, 18 September 2020 
 
 
- Active infection 
- Refusal or inability to consent 
5. Interventions 
Group 1 (PRF group): Intraoperatively prepared autologous PRF was applied to the donor 
site after graft harvesting. 
Group 2 (Control group): Standard closure without PRF application. 
6. Outcome Measures 
Primary Outcome: Absence of sensory deficit at the donor site 12 months after surgery. 
Secondary Outcomes: 
- MRI assessment of donor site healing 
- Functional outcome scores (IKDC, Lysholm) 
- Patient-reported satisfaction 
- Adverse events related to surgery or PRF application 
7. Study Procedures and Follow-up 
Patients were evaluated at baseline, and postoperatively at 4, 8, and 12 months. Clinical 
assessments included sensory testing, range of motion, and functional scores. MRI was 
performed to evaluate donor site healing. Patient satisfaction was assessed at 12 months. 
8. Ethics and Regulatory Considerations 
The study was approved by the Ethics Committee of the Faculty of Medicine, University of 
Belgrade (Approval No. 17/VI-3). Written informed consent was obtained from all 
participants prior to enrollment. The study adhered to the Declaration of Helsinki 
principles. 
9. Statistical Analysis 
Descriptive statistics were used to summarize baseline characteristics. Chi-square test and 
t-tests were used to compare categorical and continuous variables between groups. A post-
hoc power calculation for the primary endpoint was performed based on the 12-month 
results. All analyses were conducted using standard statistical software.