During a recent follow-up examination, Dr. Kenneth Johnson checked the flexibility of patient Juanita Davis new ankle, which was replaced with a prosthesis like the one pictured below. (photos by Dana Johnson)
The procedure involves replacing the ankle joint with a small device composed of two different kinds of metal, cast chrome cobalt and shiny titanium. A plastic polyethylene liner provides a base for the movable joint section. The exterior is porous, which allows the bone to grow into the prosthesis, further stabilizing the new joint.
The prosthesis fits in the tibia and fibula, Johnson said. Carefully aligning the ankle area, doctors shave out a square area of bone to put in the prosthesis.
The device uses the latest advances in computer, sensor, electric motor and battery technology to give it bionic capabilities: It is the first prosthetic with powered knee and ankle joints that operate in unison. It comes equipped with sensors that monitor its user’s motion. It has microprocessors programmed to use this data to predict what the person is trying to do and operate the device in ways that facilitate these movements.
“With our latest model, we have validated our hypothesis that the right technology was available to make a lower-limb prosthetic with powered knee and ankle joints,” said Goldfarb. “Our device illustrates the progress we are making at integrating man and machine.”