1) Prosthetics and orthotics are used to aid rehabilitation for amputees, with over 50% of amputations due to vascular disease including diabetes. 2) Advances in clinical engineering have improved prosthetics, but fitting the socket interface remains challenging due to each individual's unique residual limb. 3) Engineering solutions like CAD/CAM imaging and intelligent pressure sensors can more accurately measure and manufacture sockets as well as monitor the biomechanical conditions at the interface.

1. The application of clinical
engineering
Dr Peter Worsley
Dr Alex Dickinson
Rehabilitation International World Congress, Edinburgh, 26th October 2016
Faculty of Health Sciences

2. The Clinical Challenge
• Amputation can results from many causes:
– vascular disease (54%) – including diabetes
and peripheral arterial disease
– Trauma (45%)
– Cancer (2%)
• As with many healthcare problems, each case is
very specific to a given individual
• Amputation can also occur at many different
body locations
2

3. Evolution of Prosthetics and
Orthotics
3
• Prosthetic and orthotic devices are frequently
used to aid rehabilitation and improve quality
of life for individuals with amputation.
• Clinical engineering advances have resulted in
evolution of complex prosthetic and orthotic
devices
• However these come at a cost
• In addition there is a significant proportion of
individuals who reject their device
– Pain
– Poor fit
– Limited functional gains

4. Fitting Prosthetics and
Orthotics
• The interface between the device
and the individual is critical
• Load bearing surface between the
prosthetic and the residual limb
• Residual limbs come in all
different shapes and sizes
• Fitting a socket is often an
iterative process reliant on the
skill of the prosthetist
• Residual limbs change shape over
time
4

5. Engineering Solutions:
Residual limb imaging
5
• CAD/CAM technologies are
established in P&O device design
• Metrology-level accuracy1
• Cheap alternative systems
– What is accuracy and repeatability?
– What accuracy is really required?
– Do requirements differ with use?
5
1: Dickinson, Steer, Woods and Worsley 2016, J Rehab Res Dev 53(2) 207-218
Sidles et al 1989, JPO
WillowWoodco.com

6. Benefits of CAD CAM
• Highly accurate
• Cost/material reducing
• Repository of Shape Information
• Biofeedback
• Additive manufacturing
6

7. Engineering Solutions:
Intelligent prosthetic
pressure sensors
7
• In recent years shear sensing devices have
been developed for related applications
• Stump socket interface (Laszczak et al.
2014, 2016)
• Automotive industry (Cho et al. 2014)
• Sensors now have the ability to measure
pressure independently of shear

8. Amputee application

9. Conclusions
• Great advances in Prosthetic and Orthotic
device design
• However, the interface between the residual
limb and the socket remains challenging
• Engineering solutions exist to accurately
measure and manufacture sockets
• We can also measure the biomechanical
conditions at the interface
• This could provide an improved way of
developing sockets and an early warning
system to prevent injury.
9
Technologies are becoming cheaper and may represent opportunities to
support efficient limb fitting services in low and middle income countries

10. Thank you
Acknowledgements:
M Hulland, J Steer.
Funding provided by the Institute for Life Sciences and the Royal Academy Of
Engineering