Digital Fabrication of Lower Limb Prosthetic Sockets

This innovation insight discusses current approaches to digital fabrication of lower limb prosthetics (LLP) sockets aimed at low resourced settings. Digital fabrication of LLPs sockets has been researched for a number of decades, yet these technologies are not widely adopted, and most of the activities within this domain reside in high-income settings. However, the majority of amputees are in LMICs where there is a severe lack of access to services. It is in LMICs then, that the advantages that digital technologies offer could be of particular benefit however little to no progress in digital workflow adoption has been made to date

Evaluation of 3D Printing Technologies and 3D Printed Materials in the use of Orthotic and Prosthetic Devices

Additive Manufacturing (AM) is disrupting fabrication techniques, bringing new design possibilities with associated benefits of less waste, improved design, improved time management, and less cost. The field of Orthotics and Prosthetics (O&P) is investigating how 3D printing, a subset of AM, can be used for fabrication of O&P devices. Before this technology is fully accepted, it needs to go through rigorous testing to ensure the safety of the individuals using the devices and the longevity of the devices themselves to ensure long term-use as a viable option. Research needs to define which type of 3D printing technology and what printed materials practitioners can rely on. This study will focus on three 3D printing technologies, Fused Deposition Modeling (FDM), Selective Laser Sintering (SLS), and Multi Jet Printing (MJP) along with multiple printable materials. These printed sockets will be identical to each other and undergo 600,000 repetitions on a Tinius Olsen machine. The sockets will be visually assessed, tested with dye to identify any defects, and brought to ultimate failure using the Tinius Olsen machine. Visual and numerical fail points will be recorded which will be compared to the ISO 10328 threshold of 4480N, identifying which 3D printing technologies and printed materials will best be suited for O&P devices. As 3D printing continues to evolve and integrate into the O&P community, this study will serve as a basis to know what 3D printing technologies and materials will keep patients safe while still serving the ultimate purpose of regaining and maintaining their mobility

Design and Development of a Myoelectric Transradial Prosthesis

The loss of a limb is a life-changing event and reality for 441,000 transradial amputees in the United States. Limb loss can have substantial physical, social, psychological, and economic consequences. A prototype prosthesis was created that has sophisticated hand functionality, an adjustable and comfortable socket, and a lightweight yet durable design utilizing 3D printing, all available at a reasonable price point. The prosthesis integrated force sensors, servo motors, and a myoelectric means of control so the user may perform activities of daily living. The overall outcome was a prosthesis that met its design requirements, offering increased usability, functionality, and availability

Design and Development of a Myoelectric Transradial Prosthesis

The loss of a limb is a life-changing event and reality for 441,000 transradial amputees in the United States. Limb loss can have substantial physical, social, psychological, and economic consequences. A prototype prosthesis was created that has sophisticated hand functionality, an adjustable and comfortable socket, and a lightweight yet durable design utilizing 3D printing, all available at a reasonable price point. The prosthesis integrated force sensors, servo motors, and a myoelectric means of control so the user may perform activities of daily living. The overall outcome was a prosthesis that met its design requirements, offering increased usability,functionality, and availability

Specifying a hybrid, multiple material CAD system for next-generation prosthetic design

For many years, the biggest issue that causes discomfort and hygiene issues for patients with lower limb amputations have been the interface between body and prosthetic, the socket. Often made of an inflexible, solid polymer that does not allow the residual limb to breathe or perspire and with no consideration for the changes in size and shape of the human body caused by changes in temperature or environment, inflammation, irritation and discomfort often cause reduced usage or outright rejection of the prosthetic by the patient in their day to day lives. To address these issues and move towards a future of improved quality of life for patients who suffer amputations, Loughborough University formed the Next Generation Prosthetics research cluster. This work is one of four multidisciplinary research studies conducted by members of this research cluster, focusing on the area of Computer Aided Design (CAD) for improving the interface with Additive Manufacture (AM) to solve some of the challenges presented with improving prosthetic socket design, with an aim to improve and streamline the process to enable the involvement of clinicians and patients in the design process. The research presented in this thesis is based on three primary studies. The first study involved the conception of a CAD criteria, deciding what features are needed to represent the various properties the future socket outlined by the research cluster needs. These criteria were then used for testing three CAD systems, one each from the Parametric, Non Uniform Rational Basis Spline (NURBS) and Polygon archetypes respectively. The result of these tests led to the creation of a hybrid control workflow, used as the basis for finding improvements. The second study explored emerging CAD solutions, various new systems or plug-ins that had opportunities to improve the control model. These solutions were tested individually in areas where they could improve the workflow, and the successful solutions were added to the hybrid workflow to improve and reduce the workflow further. The final study involved taking the knowledge gained from the literature and the first two studies in order to theorise how an ideal CAD system for producing future prosthetic sockets would work, with considerations for user interface issues as well as background CAD applications. The third study was then used to inform the final deliverable of this research, a software design specification that defines how the system would work. This specification was written as a challenge to the CAD community, hoping to inform and aid future advancements in CAD software. As a final stage of research validation, a number of members of the CAD community were contacted and interviewed about their feelings of the work produced and their feedback was taken in order to inform future research in this area

The development of an adaptive and reactive interface system for lower limb prosthetic application

Deep tissue injury (DTI) is a known problem correlating to the use of a prosthetic by a transtibial amputee (TTA), causing ulcer-like wounds on the residual limb caused by stress-induced cell necrosis. The magnitude of these stresses at the bone tissue interface has been identified computationally, far exceeding those measured at the skin's surface. Limited technology is available to directly target and reduce such cellular loading and actively reduce the risk of DTI from below-knee use. The primary aim of this project was to identify whether a bespoke prosthetic socket system could actively stiffen the tissues of the lower limb. Stabilising the residual tibia during ambulation and reducing stress concentrations on the cells. To achieve this, a proof-of-concept device was designed and manufactured, a system that allowed the change in displacement of a magnet to be responded to by counterbalancing load. The device was evaluated through experimentation on an able-bodied subject wearing an orthotic device designed to replicate the environment of a prosthetic socket. The chosen sensor effector system was validated against vector data generated by the Motek Medical Computer Assisted Rehabilitation Environment (CAREN.) The project explored a new concept of reactive loading of a below-knee prosthesis to reduce tibial/socket oscillation. The evaluation of the device indicated that external loading of the residual limb in such a manner could reduce the magnitude of rotation about the tibia and therefore minimise the conditions by which DTIs are known to occur. Efforts were made to move the design to the next iteration, focusing on implementing the target demographic.Deep tissue injury (DTI) is a known problem correlating to the use of a prosthetic by a transtibial amputee (TTA), causing ulcer-like wounds on the residual limb caused by stress-induced cell necrosis. The magnitude of these stresses at the bone tissue interface has been identified computationally, far exceeding those measured at the skin's surface. Limited technology is available to directly target and reduce such cellular loading and actively reduce the risk of DTI from below-knee use. The primary aim of this project was to identify whether a bespoke prosthetic socket system could actively stiffen the tissues of the lower limb. Stabilising the residual tibia during ambulation and reducing stress concentrations on the cells. To achieve this, a proof-of-concept device was designed and manufactured, a system that allowed the change in displacement of a magnet to be responded to by counterbalancing load. The device was evaluated through experimentation on an able-bodied subject wearing an orthotic device designed to replicate the environment of a prosthetic socket. The chosen sensor effector system was validated against vector data generated by the Motek Medical Computer Assisted Rehabilitation Environment (CAREN.) The project explored a new concept of reactive loading of a below-knee prosthesis to reduce tibial/socket oscillation. The evaluation of the device indicated that external loading of the residual limb in such a manner could reduce the magnitude of rotation about the tibia and therefore minimise the conditions by which DTIs are known to occur. Efforts were made to move the design to the next iteration, focusing on implementing the target demographic

Development and evaluation of custom prosthetic devices for a companion animal utilizing additive manufacturing.

BACKGROUND AND SIGINIFICANCE: Few options exist for companion animals in need of prosthetic devices. With the rise of rapid prototyping technology, the availability and customization of prosthetic devices for individual companion animals is now a viable and cost effective alternative to the current options of a peg leg prosthetic, or wheel-assisted prosthetic device. The goals of this study were to describe the (1) specific needs and (2) biomechanics of a feline with bilateral thoracic limb amputation, (3) develop custom prosthetic devices utilizing rapid prototyping technology, and (4) describe the biomechanics of a feline with bilateral thoracic limb amputation using the custom prosthetic devices. The feline being studied in this project is a 2 year old Maine Coon feline weighing 9 lbs. She was a stray that was found with severe frostbite on her thoracic limbs. These sections of her thoracic limbs were amputated to remove the necrotic tissue. SPECIFIC AIMS: The goals of this study is to describe the (1) specific needs and (2) biomechanics of feline with bilateral thoracic limb amputation, (3) develop custom prosthetic devices utilizing rapid prototyping technology, and (4) describe the biomechanics of a feline with bilateral thoracic limb amputation with the use of the custom prosthetic devices. MATERIALS & METHODS: Fused Deposition Modeling (FDM) technology was utilized to fabricate the prosthetic devices that were designed and put through a Finite Element Analysis to simulate static loading and fatigue testing during various stages of the gait cycle. The devices were mechanically tested to ensure device failure did not occur during static loading, as well as fatigue tested to resemble continued use. vii Kinematic gait analysis was performed prior to and after use of the prosthetic devices, and outcomes were compared between the scenarios. Gait data was also compared to published feline gait data to determine any effects to the feline’s gait resulting from the amputation, and if this effect was corrected through the use of the prosthetic devices. RESULTS: FDM was a cost effective way to fabricate strong, durable prosthetic devices designed specifically for a companion animal with dual thoracic limb amputation. Mechanical testing ensured that the prosthetic devices can survive over 10,000 loading cycles at 6 N, and 3000 N of vertical force. The gait analysis performed without the use of the prosthetic devices show increased flexion of the elbows, stifle, and tarsus joint during ambulation. Gait analysis during the use of the prosthetic devices removes this additional flexion. CONCLUSION: Use of prosthetic devices can have a positive influence in the gait of companion animals with amputations. The comparison between the two data sets shows removal of the additional flexion found in the thoracic limbs when the prosthetic devices are used. This project showcases the feasibility of using additive manufacturing to create cost effect and durable prosthetic devices for use in companion animals