Date of Award

12-2024

Degree Name

MS in Biomedical Engineering

Department/Program

Biomedical Engineering

College

College of Engineering

Advisor

Scott Hazelwood

Advisor Department

Biomedical Engineering

Advisor College

College of Engineering

Abstract

This study was conducted to develop a financially accessible body-powered upper-limb prosthetic socket that can be adjusted to maintain fit and function for a growing child with a transradial amputation. The main objectives of the study were to design, manufacture, and test a device that was comfortable, functional, affordable, and adjustable. The socket was designed to be comfortable using global variables controlling the computer-aided design (CAD) model size with user-specific measurements. Comfort was also incorporated using shape-forming of the socket for specific residual limb features. The device was designed to perform the two main functions of suspension, or attachment to the residual limb, and flexion/extension of the prosthetic hand fingers based on elbow flexion. This was accomplished with a custom-fit skin-socket interface and multiple-point Velcro straps, which, paired with heat forming, allowed the socket to be adjusted by changing the shape and size of a child’s residual limb. The functional prototype of this design was manufactured through 3D printing of base socket pieces, attaching the foam lining and Velcro straps, and assembling the device with the artificial tendons (AT) connected from the distal phalanges to the tension block on the upper arm socket (UAS). This design was evaluated to verify that the device could function in distributing pressure and withstand expected static loads and to validate that the manufacturing process could produce a socket that met the specifications based on the custom measurements. Testing demonstrated that the device could be manufactured through 3D printing while maintaining critical dimension values, which provided evidence that the custom fit could be replicated reliably. The device was also shown to withstand an expected load of five pounds at the prosthetic hand of the pediatric design with factors of safety that exceeded design requirements. Pressure distribution testing proved challenging with the measurement capabilities of force-sensitive resistors (FSRs) on the tissue replica, so a rigid-body replica was used and showed paired pressure readings that were significantly different. Low sample size may be a reason for the pressure difference as the total means were similar. One limitation of the study included a need for simulated-use testing with an intended end-user, which limited the inference of these results to proof of the design concept with limited sample sizes which have a higher chance of false negative results. Future studies expanding upon this project should include clinical evaluation of the device with pediatric transradial amputees to validate practical functionality with the end-user, as well as the customizability of the device with different users and prosthetic hands. Studies could also incorporate features such as sensory feedback to improve the acceptance of the device, especially for the intended pediatric population. Despite the limitations and areas for improvement with this study, a functional prototype of a modular, adjustable transradial prosthesis for pediatric use was developed and evaluated, providing an accessible option for this gap in the pediatric prosthetic industry.

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