Although proper gait requires one to have some pronation in the foot, it's critical to have the appropriate degree of pronation as too little or too much can have extensive effects. Too much pronation of the foot results in the ankle and foot collapsing inwards too far, flattening the arch of the foot leading to potentially dangerous consequences. Since foot and ankle alignment directly influence the alignment of the knee and hip, over pronation of the feet puts additional stress on the entire lower extremity and overloads the knee with stress, transferring into genu valgum (“knock knees”) and increasing injury risk during risky movement patterns, such as those done in sports. The pronation deformity coupled with the intense exercise of athletes, increases their likelihood of experiencing injuries.
A custom orthotic is often prescribed to mitigate overpronation because every athlete's anatomy and level of exercise differs. Private shoemakers are contracted to create custom orthotics, delaying patient treatment and raising costs. Patients often turn to less costly, quicker, and more practical alternatives, resulting in a loss of revenue for the provider.
Figure 1 - Table displaying the project’s market requirements (left) and design inputs (right)
PROBLEM
CLINICAL & BUSINESS NEED
REQUIREMENTS
SYSTEM DESIGN
Foot pronation is a natural movement that distributes weight towards the medial aspect of the foot. While some degree of pronation is necessary for proper gait, overpronation can have detrimental effects, particularly in athletes. Athletes with overpronated feet experience increased stress and strain on their lower extremity chain, which can lead to injuries such as meniscus tears, knee arthritis, and knee stress syndrome.
Current solutions, such as custom orthotics, are expensive and may not be accessible to all patients, leading to a loss of revenue for clinics and suboptimal treatment outcomes for athletes. The aim of this research is to develop a cost-effective custom orthotic that can effectively alleviate overpronation and reduce the degree of genu valgum in a set population of Americans, thus lowering the risk of injuries and improving kinetics in athletes.
IMPLEMENTATION
VERIFICATION
REFERENCES
The material presented in this poster is based upon the work supported by the Department of Physical Therapy at Florida International University. We thank Dr. Thomas, Dr. Butler, Dr. Fernandez, Dr. Christie, Dr. Godavarty, Claudia Estrada, Victor Arteaga Barrios, Aleksander Aleman, the Doctor of Physical Therapy students at Florida International University, and all the Faculty of the Biomedical Engineering Department FIU for their assistance, cooperation, and mentorship that we received throughout the senior design project.
MATERIAL ASSESSMENT
Department of Biomedical Engineering, College of Engineering,
Florida International University
Spring 2023 Senior Design Project
Injury Risk Reduction Orthotic
Students: Camila Padilla, Joseph Gambin, Acaydia Campbell, Ashwin Lahori
Mentor: Dr. Anuradha Godavarty
Instructor/Faculty: Dr. Michael Christie, Florida International University
ACKNOWLEDGMENT
Figure 2- Injury Risk Reduction Orthotic Functionality
Figure 3- Injury Risk Reduction Orthotic Design
Figure 4 - Table showing material comparison across six different properties
The material chosen for the orthotics is TPU as it delivers the general properties we seek in order to create our device. It has very good thermal resistivity of up to 80°C, a temperature well beyond the scope of this device. The mechanical properties of TPU lend itself to be ahead of others with its strong tensile strength, flexural modulus, and relatively low Young’s Modulus. This combination makes it a superb material for a device that needs to be both strong and flexible. This material is also observed to be relatively easy to print with and shows minimal moisture absorbency, making it an ideal material to use for our device.
Verification Tests |
Single leg squat tests and single leg drop tests conducted using OnForm app in the Human Performance Analysis Lab |
Foot Posture Index 6 was used in the Human Performance Analysis Lab |
Compression testing using MTS Criterion Model |
GAITRite |
Measurement of degree of deflection in orthotic with patient wearing clear footwear |
Figure 5: Pressure Simulation Depicting Stress of 6.26 N/m2 (Top View)
Athlete with overpronated feet seeks correction.
Physician prescribes and prints custom orthotic based on patient measurements.
Patient wears orthotic during athletic activities to reduce injury risk.
Orthotic shape supports the feet and correctly aligns the knees
Provide an orthotic that is economically viable and promotes correct form during athletics
Market Requirements | Design Inputs |
The device must reduce peak dynamic valgus. | The degree of genu valgum must exhibit an improvement of 3-5°. |
The device must reduce overpronation in both static and dynamic postures. | Peak overpronation of the bilateral feet must exhibit an improvement by at least 25%. |
The device must withstand the user’s compression forces. | The device must bear a maximum compression load of 300 lbs both while static and during dynamic movement (Ex: rapid acceleration/deceleration, jumping, cutting, etc.) |
The device must produce minimal pressure points by evenly distributing pressure across the entire foot. | Maximum pressure in the forefoot must not exceed 32 N/cm2, the midfoot must not exceed 18 N/cm2, the hindfoot must not exceed 30 N/cm2. |
Deflection of the device when under load must be the same change in degree as the change in overpronation within +0.25°. | Thickness of the device will be between 1-5 mm to be able to manipulate the degrees of deflection. |
Tests were done both with and without an orthotic to compare results and determine any significant differences. Each leg underwent three test cycles.
Figure 6: Compression test results of right-foot orthotic showing load versus extension
Figure 7: Compression test results of left-foot orthotic showing load versus extension