Investigation of the Effects of Custom-Designed 3D-Printed and CAD-CAM-Produced Insoles in Individuals With Flexible Pes Planus
Phase: NA
Conditions: Pes Planus
Sponsor: GÖZDE KESİKBAŞ

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STUDY DOCUMENT COVER PAGE 
 
Study Title: 
The Effects of Custom-Designed 3D Printed and CAD-CAM Insole on Foot 
Posture, Plantar Pressure Distribution and Satisfaction in Individuals with 
Flexible Pes Planus 
 
Affiliation: Lokman Hekim University, Faculty of Health Sciences, Department 
of Physiotherapy and Rehabilitation   
Study Location: Ondokuz Mayıs University, Department of Orthotics and 
Prosthetics, Samsun, Turkey 
 
NCT Number: Pending   
Document Type: Study Protocol with Statistical Analysis Plan   
Document Date: November 24, 2024   
 
This document is submitted for registration and public posting at 
ClinicalTrials.gov. 
 
 
 
 
 
 
 
 
 
 

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Study Title 
The Effects of Custom-Designed 3D Printed and CAD-CAM Insole on Foot 
Posture, Plantar Pressure Distribution, and Satisfaction in Individuals with 
Flexible Pes Planus 
Study Purpose and Importance 
The purpose of this study is to investigate the effects of custom-designed insoles 
manufactured using Computer Numerical Control (CNC) and 3D printing 
technologies on plantar pressure distribution, foot posture, plantar force 
distribution, foot pain, and satisfaction in individuals diagnosed with flexible pes 
planus. This research aims to contribute to evidence-based practice in orthotic 
interventions. 
Study Site 
The study will be conducted at the Orthotics and Prosthetics Application and R&D 
Laboratories of the Faculty of Health Sciences at Ondokuz Mayıs University. 
Study Period 
The study will be carried out between April 1, 2025 and December31, 2025. 
 
Study Design 
This study will be conducted as a randomized controlled trial. 
Study Population and Sample 
The study population consists of individuals aged between 18 and 55 who have 
been clinically diagnosed with flexible pes planus and referred with a physician’s 
prescription for custom insoles to the Orthotics and Prosthetics Department at 
Ondokuz Mayıs University. 
Sample size was calculated using the G*Power 3.1.9.4 software. Based on the 
study by Ünver and Bek (2014) that investigated the effects of insole use on 
plantar contact area and pressure distribution, with an alpha of 0.05, an effect size 
of 1.53, and a power of 0.95, the required sample size was determined to be 13 
individuals per group, for a total of 26 participants. To increase statistical power 
and account for potential dropouts, the study will include 40 participants, divided 
equally into two groups (20 in each). 

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Inclusion Criteria 
Age between 18 and 55 
Diagnosed with unilateral or bilateral flexible pes planus 
At least +6 on the Foot Posture Index (FPI) 
≥5° subtalar pronation angle during standing 
No foot or lower limb treatment in the last 6 months 
Voluntary participation with written and verbal informed consent 
Exclusion Criteria 
History of lower extremity surgery 
Active athlete status 
Pregnancy or malignancy 
Neurological or orthopedic conditions limiting physical activity 
More than 1 cm lower limb length discrepancy 
Receiving any other treatment for pes planus 
Randomization and Groups 
Participants will be randomly assigned to one of two groups using a simple 
randomization method (drawing lots). 
Group 1 will receive insoles produced using CNC technology. 
Group 2 will receive insoles produced via 3D printing. 
Each participant will be evaluated before and after 8 weeks of insole use. 
 
Data Collection Tools and Assessment Methods 
Participants will be evaluated at baseline and after 8 weeks of insole use. The 
following tools will be used: 
Foot Posture Index (FPI): Assesses the degree of pes planus; individuals scoring 
+6 or higher are eligible. 

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Subtalar Angle Measurement: Conducted with a goniometer while standing 
barefoot. 
VAS-FA (Visual Analog Scale – Foot and Ankle): Evaluates pain and functional 
limitations specifically related to the foot and ankle. The scale ranges from worst 
to best function and pain levels, based on participant self-reporting. 
Plantar Pressure Analysis: Using a sensor-based platform for both static and 
dynamic measurements of plantar contact and pressure distribution. 
Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST 2.0): 
Measures user satisfaction with the orthotic device. 
Orthotics and Prosthetics Users’ Survey (OPUS) – Lower Extremity Functional 
Scale: Evaluates lower limb functionality and daily mobility performance. 
 
Data Collection Procedure 
Each participant’s group will be determined by random draw. 
• 20 participants will receive CNC-produced insoles. 
• 20 participants will receive 3D-printed insoles. 
Data will be collected through: 
• Face-to-face administration of surveys 
• Pressure mapping via pedobarographic analysis 
• Standardized clinical measurement protocols 
Statistical Analysis 
Statistical analysis will be conducted using IBM SPSS 22. Descriptive statistics 
(mean ± SD) will be used for demographic and clinical variables. 
• Normality testing: Shapiro-Wilk test 
• Within-group comparisons (pre- and post-intervention): Paired t-test 
• Between-group comparisons: Independent samples t-test 
• Repeated measures (time × group interaction): Repeated Measures 
ANOVA 
• Categorical variables: Chi-square and Fisher’s Exact Test 

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A significance level of p < 0.05 will be considered statistically significant. 
 
Informed Consent Form 
Study Title: 
The Effects of Custom-Designed 3D Printed and CAD-CAM Insole on Foot Posture, Plantar 
Pressure Distribution, and Satisfaction in Individuals with Flexible Pes Planus 
Dear Participant, 
You are invited to take part in a scientific study titled “The Effects of Custom-Designed 3D 
Printed and CAD-CAM Insole on Foot Posture, Plantar Pressure Distribution, and Satisfaction 
in Individuals with Flexible Pes Planus,” conducted by the Department of Physiotherapy and 
Rehabilitation at Lokman Hekim University. 
This study aims to examine the effects of custom-made insoles produced with Computer 
Numerical Control (CNC) and 3D printing methods on foot posture, plantar pressure 
distribution, foot pain, and user satisfaction in patients diagnosed with flexible pes planus. 
You will be provided with a custom-designed insole. You are expected to use it regularly for 8 
weeks. These insoles are not associated with any side effects. Your honest participation and 
answers will help determine which insole model is more effective, and may contribute to 
improvements in future orthopedic practices. 
Voluntary Participation and Confidentiality 
Participation in this study is completely voluntary. You may refuse to participate or withdraw 
at 
any 
time, 
without 
any 
consequences 
or 
loss 
of 
rights. 
Your personal information will remain confidential and will be used only for scientific purposes. 
Your name will not appear in any reports or publications resulting from this research. 
Evaluation Process 
You will be asked to complete several questionnaires and undergo evaluations at the beginning 
and at the end of the 8-week insole usage period. Each session will take approximately 30 
minutes. 
You are expected to: 
• 
Wear the insole regularly 
• 
Answer all the questions sincerely 
• 
Attend both evaluation sessions 
 
 
 

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Contact Information 
If you have any questions or concerns regarding the study, you may contact the following 
researchers: 
Principal Investigator: 
Prof. Dr. Nilgün Bek 
Lokman Hekim University 
Department of Physiotherapy and Rehabilitation 
  +90 543 553 03 70 
  nilgunbek@gmail.com 
 
Research Assistant: 
Specialist Orth. Prost. Gözde Kesikbaş Kurt 
Ondokuz Mayıs University 
Department of Orthotics and Prosthetics 
  +90 530 040 78 95 
  gozdekskbs@gmail.com 
Consent Statement 
☐ I have read and understood the information above. I voluntarily agree to participate in this 
study. 
 
Participant 
Name 
& 
Surname: 
...................................................... 
Signature: 
................................................................. 
Date: ___ / ___ / 2025 
Witness 
(if 
needed) 
Name 
& 
Surname: 
...................................................... 
Signature: ................................................................. 
Researcher 
Name 
& 
Surname: 
...................................................... 
Signature: .................................................................