Bionic leg brace

12 June 2009

A bionic leg brace that supplements muscle strength is helping stroke patients to walk again.

The so-called Tibion PK100, or PowerKnee, is a robotic boot that inserts into the user’s shoe and extends up to mid-thigh. It is equipped with multiple sensors and microprocessors that can detect the user’s actions – such as making a transition from sitting to standing, or climbing stairs – and adjust its support accordingly.

Jean Nelson, vice-president of marketing of Tibion, the maker of the PowerKnee, based at NASA Research Park in Moffett Field, said: ’Basically, the device determines what the patient is trying to do and then assists in that action. The computer’s learning algorithm allows it to adapt after the first few steps.’

In addition to helping patients with neuromuscular impairment due to stroke, multiple sclerosis or Parkinson’s disease, Tibion designed the PK100 to serve individuals suffering from osteoarthritis or those recovering from knee surgery.

The battery-operated device can be personalised according to a user’s height, weight and physical needs. For example, the knee angle can be adjusted for those who do not have full range of motion.

The first commercial model of the PK100 was unveiled in February at a meeting of the American Physical Therapy Association in Las Vegas.

The University of California San Francisco (UCSF) is one of the first places to test it out. After just four weeks, each of the UCSF patients that used the device reported significant improvements in their physical capabilities.

Eric McHuron, who suffered a stroke in December 2003, shaved nearly seven seconds off his unassisted 10m walking pace after training with the PK100.

Eric McHuron, who suffered a stroke in December 2003, increased the distance he was able to walk over a six-minute period by more than 20 per cent, from 170m to 207m
Photo credit: Susan Merrell, UCSF