Pedi-knee: Prototype Development of A 3D Printed Pediatric Knee Joint

Abstract

Background: Paediatric prosthetic knee design remains challenging due to factors such as rapid growth, high activity levels, and the need for lightweight, cost-effective solutions. Conventional knee joints often fail to balance functionality, affordability, and adaptability, particularly in low-resource settings. Advances in 3D printing and CAD modelling offer promising alternatives for developing customized and efficient prosthetic components for children. Aim: To design and evaluate a lightweight, cost-effective paediatric prosthetic knee joint (Pedi-Knee) using 3D printing technology. Study Design: Prototype development study. Place and Duration of Study: Indian Spinal Injuries Centre, New Delhi, India, 2024–2025. Methodology: The prosthetic knee joint was designed using CAD software and fabricated using additive manufacturing with PA12 nylon. The design incorporated a single-axis mechanism to allow controlled flexion and extension. Mechanical properties, stress distribution, weight, fabrication time, and cost efficiency were evaluated. Results: This study describes the design and fabrication of Pedi-Knee, a pediatric single-axis prosthetic knee developed through CAD modeling and selective laser sintering (SLS) using PA12 (also known as Nylon 12). The prototype achieved a weight of approximately 240 grams and provided a smooth range of motion from 0 to 120 degrees. A modular pyramid connector ensured easy compatibility with existing pediatric prosthetic systems. Pedi-Knee fabrication requires shorter periods. By combining simplicity, durability, and accessibility, Pedi-Knee presents a practical and scalable solution to address a longstanding gap in pediatric prosthetic care. Discussion: The findings suggest that a 3D-printed single-axis prosthetic knee joint can provide a practical balance between functionality, affordability, and customization for paediatric users. While advanced prosthetic knees offer superior performance, their limitations in cost and complexity restrict their use. The proposed design addresses these gaps; however, further clinical validation is required to assess long-term performance and user outcomes. Conclusion: The Pedi-Knee provides a lightweight, affordable, and clinically viable solution for pediatric prosthetic applications.