Computers Have Entered The Realm Of Artificial Limbs

Have you ever wondered how you would react to losing an arm or leg? Would you use an artificial arm or leg known as a “prosthesis?”

In my life work as an orthopaedic surgeon, I occasionally cared for people with above-knee and below-knee amputations, never imaging how I personally would cope with and accept loss of a limb.

A month ago during conversation with fellow retired friends at our weekly breakfast get-together, I learned how citizens of the African country of Sierra Leone had arms or legs intentionally amputated by rebels to discourage opposition of the civil war. This shocking knowledge made me realize if I had an amputated leg, I would feel like half a person.

The emotional impact of losing a limb was honestly stated by a 16-year-old young lady, Memunata Mansaray, featured on the cover of the February 2013 magazine, Rotarian, who had one arm amputated at age 2 – at the same time her parents were killed in the Sierra Leone civil war.

“I feel less human because I have one arm,” she said, “and it makes me feel uncomfortable. I can do anything that anyone with two arms can do and more.” She now plays high school soccer in Washington, D.C.

Today, arm or leg prostheses are prescribed for people who need amputation as medical treatment for incurable bone infection, malignant tumors and poor blood supply called ischemia. I personally have a vivid recollection of a saintly gentleman I cared for whose leg was amputated above the knee for a persisting bone infection. He accepted an above-knee, artificial leg made by a local prosthetist. After rehabilitation with physical therapists, he walked independently and later became an inspirational speaker convincing listeners how a little bit of bad luck and tragedy in their life can be overcome.

As one can imagine, accepting and using an artificial limb, in particular a leg, the most common prosthesis, is a psychological and physical challenge. Self pity, increased physical effort to move the leg prosthesis, and difficulty performing normal activities of running, climbing stairs, and playing sports are obstacles facing the amputee.

This month, Dan Wojcik, a certified prosthetist at Nelson Prosthetics in Jamestown, met with me to explain how microprocessor computers revolutionized artificial legs in the last 10 years, permitting normal walking, stair climbing and even running.

The age of a bionic leg has arrived. Sensors in the prosthetic foot transmit 1,000 electrical impulses a second to microprocessors in the knee, signaling the knee to resist or bend depending on where the foot is positioned during a complete step from heel strike to push off whether walking, running or climbing stairs.

Therefore, if a person is going down stairs one leg after the other in a normal fashion, computers in the prosthetic foot signal the knee to create resistance when the person steps down with the normal leg because all weight is on the flexed or bent knee in the artificial leg, but the prosthetic knee will not buckle or give way.

Similarly, going up stairs leading with the artificial leg requires the bionic knee to accept body weight, become straight, and then allow leg muscles to push one up to the next step without the knee giving way. This technology comes with a price, $40,000 for a bionic knee and $20,000 for a bionic foot. Battery life for the knee microprocessor is two days before recharging is necessary. Present day prostheses can be held in place with suction, thereby eliminating straps, laces and belts used in the past.

During the summer at the London Olympic Games, we were treated to a spectacle by the South African sprinter, Oscar Pistorius, a bilateral below-knee amputee competing alongside the world’s fastest men. His prostheses were temporarily fitted with curved metal blades designed to simulate the hind foot of the cheetah, the fastest mammal on Earth.

Accepting an amputation particularly in later life is a challenge, but with emotional support the use of a prosthetic leg is becoming easier with computer technology.