3D Printing Revolutionizing Orthotics Manufacturing

Orthotics, the field of medical devices focused on enhancing neuromuscular and skeletal systems, has been significantly transformed by 3D printing technology.

Introduction

Orthotics, the field of medical devices focused on enhancing neuromuscular and skeletal systems, has been significantly transformed by 3D printing technology.

This article explores the various processes involved in 3D printed orthotics, their applications, advantages, and the evolving trends in digital design technology.

Functions and Types of Orthotics

Functions of Orthotics

Orthotics serve several functions:

Stabilization and Support

Restrict abnormal movement to maintain joint stability and weight-bearing ability.

Fixation and Correction

Correct deformities or prevent their progression by immobilizing affected areas.

Protection and Load Exemption

Immobilize limbs or joints, maintain alignment, and relieve weight-bearing joints.

Reparation and Assisted Movement

Use devices like rubber bands or springs to compensate for muscle loss and assist limb movement.

Types of Orthotics

Upper Extremity Orthoses

Elbow Wrist Hand Orthosis. Source: Orfit Industries

• Shoulder, Elbow, Wrist, and Hand Orthosis
• Elbow Wrist Hand Orthosis
• Wrist-Hand Orthosis
• Hand Orthosis

Lower Extremity Orthotics

Foot and ankle orthosis (AFO). Source: Orthotics Plus

• Hip, Knee, Ankle, and Foot Orthosis
• Knee Orthosis
• Knee-Ankle-Foot Orthosis
• Ankle-Foot Orthosis
• Foot Orthosis

Spinal Orthotics

Spinal orthosis. Source: Access Prothetics

• Cervical Orthosis
• Thoracolumbosacral Orthosis
• Lumbosacral Orthosis

3D Printed Orthotics: Why and How

Advantages of 3D Printed Orthotics

3D Printed Knee Orthosis. Source: Shapeshift3D

1. Rapid Customization: The inherent flexibility of 3D printing technology allows for swift adaptation to individual anatomical requirements. Each orthotic device can be precisely tailored to suit the unique needs of the patient.
2. Functional Integration: 3D printed orthotics seamlessly integrate various functional elements into a single design. This enables the incorporation of specialized features that enhance support, movement, and therapeutic outcomes.
3. Lightweight Design: Leveraging advanced materials and precise layering, 3D printed orthotics maintain their structural integrity while remaining remarkably lightweight. This not only enhances wearer comfort but also minimizes the impact on natural movements.
4. Improved Comfort: The ability to intricately design orthotic structures ensures a more ergonomic fit, reducing pressure points and discomfort commonly associated with traditional devices.
5. Aesthetic Appeal: 3D printing allows for creative design possibilities, enabling orthotics to be visually appealing and harmoniously blend with clothing and personal style.

Types of 3D Printing Processes for Orthotics

Material Extrusion Processes

• Fused Deposition Molding (FDM)
• Fused Filament Fabrication (FFF)
• Materials: PA, PP, TPU, fiber-reinforced composite materials

Powder Bed Processes

• Selective Laser Sintering (SLS)
• High-Speed Sintering (HSS)
• Multi-Jet Fusion (MJF)
• Materials: PA12, TPU powder

VAT Photopolymerization Processes

• Digital Light Processing (DLP)
• Digital Light Synthesis (DLS)
• Materials: Elastic photosensitive resin

Process for 3D Printed Orthotics

1. Examining the patient's condition
2. Prescribing customized orthoses
3. Acquiring patient imaging data through 3D scanning
4. Designing personalized orthotic models
5. 3D printing the orthosis
6. Post-processing
7. Fitting the orthosis to the patient
8. Monitoring and feedback for adjustments

Applications of 3D Printed Orthotics

Foot and Ankle Orthosis (AFO)

Intricate AFO design by 3D printing. Source: Shapeshift3D

Foot and ankle orthosis, commonly referred to as AFO, is a specialized orthotic device designed for patients with ankle soft tissue injuries and foot instability. Its application extends to personal protective care during sports activities.

Clinical Applications

AFOs are beneficial in treating various conditions including:

• Cerebral palsy
• Stroke
• Fractures
• Spinal cord injuries
• Peripheral nerve injuries

Types of Ankle Foot Orthosis

There are several types of AFOs, including:

• Passive AFO (hinged and non-hinged)
• Semi-active AFO
• Active AFO

Manufacturing Requirements for AFOs

1. Strength for providing adequate support
2. Flexibility to ensure comfort during walking
3. Breathability to prevent excessive sweating
4. Lightweight design to minimize energy expenditure while walking
5. Aesthetic appeal for seamless integration into clothing
6. Ease of customization and molding

Evolution of AFO Manufacturing

The production of Ankle Foot Orthoses (AFOs) has progressed significantly. It started with molding thermoformed plastic sheets around plaster casts. Then, pre-impregnated carbon fiber sheet laminates were shaped around plaster casts for increased durability.

Currently, direct 3D printing is the cutting-edge method, enabling efficient and personalized AFO fabrication. This evolution highlights the continuous pursuit of enhancing orthotics through technological advancements.

Spinal Orthoses

3D Printed Spinal Orthosis. Source: Unionfab

Spinal orthoses are globally acknowledged as effective treatments for scoliosis, a condition characterized by abnormal spinal curvature.

Advantages and Challenges of 3D Printed Spinal Orthoses

3D printed spinal orthoses offer distinct advantages:

• Customized and comfortable scoliosis orthoses tailored to individual needs and biomechanical analysis.
• Utilization of diverse production materials to meet varying patient material requirements.
• Porous design enhancing breathability and reducing skin and soft tissue complications.
• Simpler, faster, and cleaner production process aligned with human body characteristics and treatment needs.

However, 3D printed spinal orthoses face certain challenges:

• Longer processing cycles compared to traditional methods
• Higher costs due to the expense of materials

Spinal Orthoses Manufacturing Methods

Various manufacturing methods for spinal orthoses include:

• Gypsum Process (Manual Process):
  Plaster bandage
  Model creation
  Plaster paste application
  Molding
• CAD/CAM (Digitizing):
  3D scanning for data acquisition
  CAD design
  Model machining
  Molding
• CAD/3D Printing (Digitizing):
  3D scanning for data collection
  CAD design
  3D printing

Hand Orthoses

3D Printed Elbow Wrist Hand Orthosis. Source: Unionfab

Applications of Hand Orthoses

Hand orthoses find therapeutic applications in treating:

• Fractures
• Sprains
• Ligament injuries
• Misalignment

Advantages of Hand Orthoses

• Lightweight design
• Waterproof properties
• Compatibility with X-rays
• Wearability under clothing
• Facilitation of limited movement

Trends in Digital Design Technology for Orthotics

Digital design and manufacturing of orthotics involve computer-aided design/manufacturing, 3D scanning, medical modeling, and finite element analysis.

Early adoption saw manual trimming but has shifted to software-based trimming due to advancing software and AI-driven design tools. Software aids in comparing body scans and X-rays, reducing design errors.

Utilizing 3D Scanning for Patient Data

3D scanning for patient data acquisition eliminates secondary injuries and improves accuracy compared to manual methods.

This enhances orthotics customization, fit, comfort, and therapeutic effectiveness.

Conclusion

3D printing has revolutionized orthotics manufacturing, offering customized solutions with functional benefits. As technology advances, orthotics design and production will continue to become more efficient, patient-centric, and effective.