Sunday, March 22, 2009

New prosthetic can anticipate, adapt to movement

From the St. Cloud Times in Minnesota. In the picture, Cale Konetchy of Otto Bock HealthCare helps Don Miller of St. Augusta adjust to walking with the C-Leg at Hanger Prosthetics & Orthotics in St. Cloud.

It looks like something out of “The Six Million Dollar Man” — a computer-controlled prosthetic leg costing tens of thousands of dollars that blurs the line between man and machine.

Fashioned around a lightweight carbon fiber frame, the C-Leg prosthetic uses on-board sensors and a microprocessor to anticipate and adapt to the movements of an above-knee amputee.

“The difference is when patients walk with a C-Leg, they don’t have to think about how to walk anymore. It will never buckle on you,” said Cale Konetchy of Otto Bock HealthCare.

With its U.S. headquarters in Minneapolis, Otto Bock offers products and services to help people increase and retain their physical independence. Representatives were at Hanger Prosthetics & Orthotics, a patient care provider, in St. Cloud on March 19.

“On average, the cost of the entire prostheses is about $40,000,” said Kristen Knox, an Otto Bock HealthCare marketing manager at the demonstration at Hanger.

Hanger practice manager and certified prosthetist Cooper Gehrman and Konetchy calibrated each C-Leg individually at Hanger’s 25th Avenue North site, using a laptop and Bluetooth technology.

The C-Leg’s lithium-ion battery powers a knee angle sensor, which supplies details to the built-in microprocessor controlling the prosthetic’s hydraulic cylinder, which moves the leg.

“The microprocessor is using the force-sensing pylon and the knee angle sensor in the knee to look at the patient’s gait 50 times per second and to adjust for the flexion and extension valves in the knee to accommodate the speed at which a patient walks,” Konetchy said.

“Whether the amputee is technologically savvy is something to take into consideration because if the patient doesn’t remember to charge it, it’s not going to do him any good,” Gehrman said.

At Hanger, Central Minnesotans were selected to try the C-Leg, which can be optimized for the user’s interests and daily activities.

The C-Leg by Otto Bock was the world’s first fully microprocessor-controlled prosthetic knee, Knox said.

“The Otto Bock Roadshow is something we started four years ago to let people sort of try the technology before they buy it ... before they make the investment,” she said.

“A lot of times with a practitioner, once they’ve billed for the device, that includes their time for the next three years typically, so you’re kind of billing up front for the patient care.”

The first C-Leg was sold in 1999 and about 30,000 of them have since been sold worldwide. They allow users to speed up or slow down, take on hills or slopes, and recover from stumbles.

The latest modifications to the C-Leg include a wireless remote control to easily switch between modes and a standing mode that allows the user to relax and take weight off his or her sound limb.

“The term ‘bionic’ in the prosthetics industry has been coming up more nowadays as technology becomes more microprocessor-based, adapting to the patient’s day-to-day needs,” Gehrman said.