RAEng MacRobert award goes to Blatchford’s smart prosthetic leg

The Royal Academy of Engineering has awarded its top innovation prize, the MacRobert Award, to a team of engineers which has developed the world’s most advanced commercially-available prosthetic lower leg.

The Linx smart lower-limb prosthetic reduces users' fatigue and increase their confidence and ability to tackle a variety of terrain and activities
The Linx smart lower-limb prosthetic reduces users’ fatigue and increase their confidence and ability to tackle a variety of terrain and activities

Prof Saeed Zahedi, Nadine Stech, Andy Sykes, David Moser and Rob Painter, who all work for Basingstoke-based clinical rehabilitation equipment producer Blatchford, won the award for the Linx prosthetic lower leg, which incorporates robotic microprocessor control of the knee and ankle joints.

Blatchford's team leader and techncal director Prof Saeed Zahedi
Blatchford’s team leader and techncal director Prof Saeed Zahedi

The Linx system uses sensors in knee and ankle that communicate with a central processor, adjusting the contributon of assisting and braking mechanisms in both joints to adapt to the user’s gait, activity, environment and terrain, handling 400 messages per second between the two joints. This means that the prosthetic will, for example, lock when the user is standing still, allowing the user to relax and eliminating the need to hold the limb steady and balance, which requires energy and concentration with a conventional prosthesis. Unlike the powered below-the-knee prosthetics developed bu Hugh Herr of MIT, the Linx system works for above and below-knee amputations and do not use motor assistance. Linx users do not have to meticulously plan their days to take account of the terrain they might encounter, giving them more freedom and confidence. The knee is programmed over Bluetooth when first fitted, then recalibrates itself some 4000 times over the course of a typical day.

Chair of the MacRobert judging panel, Dame Sue Ion, commented: “Blatchford has combined a compassionate approach to patient needs with huge ambition and exceptional systems engineering. In doing so, it has created the first-ever integrated lower limb that behaves like a human leg, and produced a platform technology that signifies the beginning of the next generation of prosthetics” Dame Sue also noted that Blatchford has retained its manufacturing base in the UK, although the National Health Service has deemed Linx to expensive to supply to patients; most users are in the US, Germany and Norway.