CUSTOMISATION OF COSMETIC COVERS FOR ARTIFICIAL LIMBS

This proposal combines academic expertise in digital manufacturing and heterogeneous foams (University of Strathclyde, Department of Design, Manufacture and Engineering Management) with prosthetics practitioners (University of Strathclyde, National Centre for Prosthetics and Orthotics) and non-academic partners, manufacturers (Blatchford Ltd.) and service users (PACE Rehabilitation, an SME), to investigate the feasibility of revolutionising the functionality and appearance of prosthetic cosmoses. Currently, flexible polyurethane foam cosmoses are a widely used component of prostheses for limbs. In a very labour intensive process, cosmoses may be machined from slab stock to a semi finished form and then shaped further to match patient requirements. An ordinary covering stocking is often added to enhance the cosmetic appearance of the prosthesis. Amputees cover their metal orthopaedic limb (i.e. artificial leg, arm, etc) with a two-fold function cosmesis: it protects the expensive equipment and, in theory, it provides a better aesthetic appearance to the patient's orthopaedic prosthesis. The reality is that cosmetic covers underperform the artificial limb, attract dirt, are non-water proof or fire resistant, impede the normal functioning of joint(s) and have a poor visual finishing which hinders the patient's psychological recovery and acceptance of their new condition and appearance.Although widely used, the foam cosmesis neither deforms like human limbs nor withstands repeated flexure, and its appearance is far from resembling human skin. These problems have their root in the standardized nature of the foam used; with a homogeneous and uniform pore size throughout the material, the stiffness will also be constant and consequently it will bend in an 'unnatural' way. Ultimately the highly stressed areas will fail, and the foam will tear at the joints (especially on the knee). The mechanical properties of foams are determined by their cellular structure; so small cells with thicker walls create stronger, stiffer materials than large open pours. Traditional manufacturing methods have fabricated cosmoses from blocks of homogeneous foam resulting in objects that have uniform mechanical properties. However it is also well known that variation in cellular structure can produce impressive combinations of strength and flexibility. To date, no manufacturing process for mass production has existed capable of dynamically varying the cellular structure of foamed material. Consequently, a controlled variation of features in the cosmesis to suit patient's movements and needs is not available. This proposal seeks to enable the mass customization of functionally graded foams, so they can be fitted to orthopaedic limbs and replicate the movement of the existing (healthy) limb. Using recently reported advanced manufacturing techniques never used before in this field, (e.g. computational modelling and simulation of foamed materials' behaviour, rapid prototyping technologies, ultrasonic irradiation, etc), as well as cutting-edge technology in scanning and measurement of materials properties, we aim to provide end-users (both practitioner prosthetists and patients) with a method of influencing shape, appearance, function and behaviour of foam cosmoses for orthopaedic applications.This proposal envisages a 2 year work program during which the commercial partners will help with patient satisfaction interviews, will input directly into the specification of requirements, and assist with the assessment of results. Our intention with the outcomes of this project is to pave the way for our partners to apply the results and implement them in the production process, allowing them to take the work forward and exploit the benefits that the project's output will provide to the relevant industry, rehabilitation services, carers (i.e. orthotists), the National Health Service and, most importantly, the patient.

This project will have an impact on the following: patients, healthcare professionals, relevant companies (especially on our industrial partners) and also on several academic disciplines. Patients: The prospect of getting better cosmoses, which are more durable, easier to maintain and clean, with a more realistic tactile feel and 'tailorable' to their specific needs (i.e. adjustable at the joint(s), different materials and finishes, etc) adds a vital ingredient of flexibility in the physical and psychological recovery process of amputees. Healthcare professionals (clinicians) and the NHS: The design of cosmoses will address improved functionalities and mechanical behaviour as well as methods for easy removal from the components for the clinician's manoeuvre. This will reduce numbers of visits and waiting periods and reduce the time a patient has to attend for maintenance and further adjustment to the prosthetic to accommodate changes in the foam stiffness. Relevant industry: specifically PACE and Blatchford, partners. Improving competitiveness in the market with higher quality cosmoses is a central interest in this research programme. The reduction of man hours and the automation of the production process is a major objective for the industry in the field. The investigators working on this project will obtain a direct benefit in terms of enhancement of skills, broader knowledge of the field and a better understanding on the supply chain in services for patients. As well as the aforementioned professionals in the field of prosthetics and orthopaedics, manufacturers of cosmoses and clinicians, academic beneficiaries will include other researchers working in the fields of (i) functionally graded materials, functionally tailored materials and foams; (ii) advanced manufacturing technologies; and (iii) multi-physics simulation and materials modelling. The modelling of the manufacture of enhanced cosmoses will have a positive impact for researchers working on heterogeneous systems, anisotropic materials and bio-inspired artefacts. This is a collaborative proposal among the University of Strathclyde (Department of Design, manufacture, Engineering Management; and the National Centre for Prosthetics and Orthotics), and the industrial partners PACE Rehabilitation and Blatchford. They will play an active role in the project as members of the consortium and also as fully involved executors of the project methodology in order to enhance exploitation of results and increasing impact for the benefit of the end-users. Blatchford is the manufacturer and supplier of the components used in orthopaedics, and PACE, an SME which works at the interface with patients providing prosthetic and orthotic clinical services, is a service user of these items. They bring to the project a synergistic collaboration and consultation on best practice and first-hand experience from the manufacture and servicing of the prosthetic components, ensuring appropriate exploitation of this project's outcomes. Together, the companies with the academics provide the project with a clear pipeline from concept, proof of principle, prototype and validation, scale-up and integration in their production process for further exploitation and commercialisation for the benefit of the end users (both patients and healthcare professionals). The dissemination mechanisms established in this project are (i) academic publications in journals covering the fields of Orthopaedics, Materials, Advanced Manufacture, and Health, as well as presentation at relevant Conferences, at least one national and one international; (ii) publicising on the university and partner's websites, (subject to any IP restrictions) (iii) a seminar at the end of the project to disseminate immediate results from the project which will bring together policy-makers, manufacturers, end users, clinicians (prosthetists, orthotists, orthopaedic and rehabilitation consultants, etc), and patients.