In 1997 the world was introduced to the first microprocessor prosthetic knee. This innovative device has changed the lives of thousands of above knee amputees since its introduction to the US market in 1999. The advent of the microprocessor knee has been a game changer in the field of prosthetics.
The C-Leg, by Otto Bock, utilizes a microprocessor to analyze and respond to to sensors at a rate of 50 times per second. The constant analysis of terrain and gait provides the amputee with a knee that is responsive in real time. Many C-Leg wearers report an increased sense of stability, especially when variations in walking speed occur.
The knee works by controlling the amount and angle of movement (flexion), within the "joint." A system of hydraulic cylinders are controlled by the microprocessor after the information from the sensors is received. The knee is allowed to bend to a certain angle based upon the combined readings from the angle and movement sensors.
When the prosthesis is not fully weighted, the knee remains in free-swing. After they are fully trained and prosthetic trust has been developed, many wearers note that the C-Leg takes the thought process out of walking. Various modes are available to accommodate for a variety of activities, ranging from walking to riding a bike.
Unlike mechanical knees, the C-Leg allows the user to vary their walking speed without adjusting their gait as well as enabling the individual to walk down the stairs in a leg-over-leg pattern. Should the amputee stumble, the knee will adjust without buckling. Because of the speed of the microprocessor, the knee responds to missteps and stumbles before the human body.
Here is a little tidbit of trivia you can use to impress your amputee friends. Most people assume that the "C" in C-Leg stands for computerized or computer. In actuality, the "C" refers to the original model number of the device, which was known as the 3C100 knee. It was shortened to C-Leg and the name has been applied to each version manufactured.
Although the C-Leg isn't for every above knee amputee, it has proven to be a valuable tool for many of our patients. If you are interested in learning about the C-Leg and if this knee is for you, give us a call.