Transtibial prosthetic socket design: Understanding the requirements for a healthy residual limb

Lead Research Organisation: University of Bristol
Department Name: Aerospace Engineering


A prosthesis serves to restore the functions of an amputated limb partially. A prosthesis is, therefore, a gateway for a restored social and economic life for many. With over 30 million lower leg amputees worldwide, the prosthesis which are accessible to most must sufficiently cater to the user's needs. However, with current transtibial prosthesis (for below the knee amputations) designs, around 25 - 57% of users choose to abandon their prosthesis. This is primarily attributed to the interface between the amputated limb and the prosthesis, which is comprised of the prosthetic socket and liner. The high proportion of abandonment indicates there is much room for research and development. The lack of effective design is due to the difficulty in holistically understanding and solving the design challenges because this requires multidisciplinary knowledge across biology, biomechanics, mechanical and manufacturing engineering, clinical knowledge, and experience.

In the literature, there is clear interconnectivity and interplay between the socket design parameters and the amputated limb. This systematic nature is largely not considered in the development of prosthetic socket design. The literature in which systematic nature is considered a clear improvement in design outcomes is recorded. This project, therefore, aims to expand in that trajectory by considering a holistic approach to design. And thus, answer the research question: how to design and manufacture an effective and accessible prosthetic socket?

The method to achieve this is outlined below in the objectives of this PhD project:

- To holistically investigate the residual limb system and how to maintain it healthy in everyday use.
- To investigation the limitations to current socket design and modelling techniques
- To investigate the design using Axiomatic design principles, consideration for the design for manufacture and biomimicry to find suitable design parameters for the socket.
- Using the previous investigations to derive a novel manufacturing and design process for prosthetic sockets
- To test and validate the design through the development of computer and physical models of an amputated limb and socket.

The potential application includes the production of a low-cost prosthetic socket which can be modified to include other types of amputation. Additionally, this research could improve the human-machine interaction, for example, in wearable devices and other wearable equipment.

Planned Impact

There are seven principal groups of beneficiaries for our new EPSRC Centre for Doctoral Training in Composites Science, Engineering, and Manufacturing.

1. Collaborating companies and organisations, who will gain privileged access to the unique concentration of research training and skills available within the CDT, through active participation in doctoral research projects. In the Centre we will explore innovative ideas, in conjunction with industrial partners, international partners, and other associated groups (CLF, Catapults). Showcase events, such as our annual conference, will offer opportunities to a much broader spectrum of potentially collaborating companies and other organisations. The supporting companies will benefit from cross-sector learning opportunities and

- specific innovations within their sponsored project that make a significant impact on the company;
- increased collaboration with academia;
- the development of blue-skies and long-term research at a lowered risk.

2. Early-stage investors, who will gain access to commercial opportunities that have been validated through proof-of-concept, through our NCC-led technology pull-through programme.

3. Academics within Bristol, across a diverse range of disciplines, and at other universities associated with Bristol through the Manufacturing Hub, will benefit from collaborative research and exploitation opportunities in our CDT. International visits made possible by the Centre will undoubtedly lead to a wider spectrum of research training and exploitation collaborations.

4. Research students will establish their reputations as part of the CDT. Training and experiences within the Centre will increase their awareness of wider and contextually important issues, such as IP identification, commercialisation opportunities, and engagement with the public.

5. Students at the partner universities (SFI - Limerick) and other institutions, who will benefit from the collaborative training environment through the technologically relevant feedback from commercial stakeholder organisations.

6. The University of Bristol will enhance their international profile in composites. In addition to the immediate gains such as high quality academic publications and conference presentations during the course of the Centre, the University gains from the collaboration with industry that will continue long after the participants graduate. This is shown by the

a) Follow-on research activities in related areas.
b) Willingness of past graduates to:

i) Act as advocates for the CDT through our alumni association;
ii) Participate in the Advisory Board of our proposed CDT;
iii) Act as mentors to current doctoral students.

7. Citizens of the UK. We have identified key fields in composites science, engineering and manufacturing technology which are of current strategic importance to the country and will demonstrate the route by which these fields will impact our lives. Our current CDTs have shown considerable impact on industry (e.g. Rolls Royce). Our proposed centre will continue to give this benefit. We have built activities into the CDT programme to develop wider competences of the students in:

a) Communication - presentations, videos, journal paper, workshops;
b) Exploitation - business plans and exploitation routes for research;
c) Public Understanding - science ambassador, schools events, website.


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