Dan Rodricks: A giant step for Tony, with the help of a good therapist and a bionic knee | COMMENTARY

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Tony Gerst trains to use Ossur's Power Knee with physical therapist and amputation specialist Michelle Jamin at Real Life Prosthetics in Abingdon.

Tony Gerst took a big step the other day, and his physical therapist expressed her elation with a sound that is difficult to describe.

I’ve never heard anything like it — neither whoop nor squeal, but some sort of high-pitched “Wheee!”


Yes, maybe “Whee!” is what I heard, though I’m still not sure that best describes Michelle Jamin’s expression of happiness at her 77-year-old patient’s achievement.

With the help of a new product — what its manufacturer calls a motor-powered microprocessor knee, or MPK — Tony Gerst was able to climb one step with his right leg or, to be precise, with what remains of his right leg. It was amputated — first below the knee, later above it.


Until a few months ago, when he started using a bionic device called the Power Knee, Gerst was only able to negotiate a curb or climb a step by leading with his left leg. The other day, working with Jamin, he was able to lead with his right. The new device gave him the power he needed to pull that off, and when it happened, Jamin uttered the happy sound I’d never heard before.

Background: Tony Gerst used to own and operate Boxcar Avenue, an ice cream shop in Perryville in Cecil County. But he had to give it up several years ago when health problems developed following reconstructive surgeries on his right ankle.

“His first amputation was in 2008,” Jamin says. “It was originally a below-knee amputation due to pain and gangrene. … In 2020, he had three revision surgeries and had a difficult time with his wound healing due to poor vascularization of the limb. Ultimately, he developed osteomyelitis [a bone infection] in the femur and required an above-knee amputation in December 2021.”

The following spring, Gerst received his first above-knee prosthesis and started working with Jamin, an amputee specialist, in a room at Real Life Prosthetics in Abingdon.

With regular therapy, he made progress and was ready to go bionic by fall. The prosthetists at Real Life outfitted him with a Power Knee just before Christmas. They also gave him a microprocessor-controlled ankle.

The manufacturer of both devices is Ossur, a longtime prosthetics developer based in Iceland. Its website says the Power Knee “helps fill the absence of muscle power.” Gerst finds it particularly helpful when he needs to rise from a chair. He works with Jamin on that during therapy sessions.

“The Power Knee is replacing the muscle that has been taken from him,” she says. “So it’s replacing hamstrings, replacing his quad, and actively progressing him forward.”

“It makes a big difference,” Gerst adds. “It helps move you along faster.”


It also reduces the amount of energy he needs to get around and relieves the stress Gerst had to put on his left leg to get out of a chair or up a ramp.

“Now he’s got power in both legs,” Jamin says. “He’s able to balance more between the two.”

When his motions prompt the microprocessor, the Power Knee makes a whirring sound reminiscent of the movements of a movie robot. Some people, Gerst says, get a little startled when they hear that.

“It can be loud at times,” says Jamin, “but the function that it gives people really outweighs the sound issue.”

Motor-powered prosthetic limbs have been a thing for several years.

Last fall, the College of Engineering at the University of Utah rolled out the Utah Bionic Leg, promising to “help people with amputations, particularly elderly individuals, to walk much longer and attain new levels of mobility.” The Utah Bionic Leg uses motors, processors and artificial intelligence to give amputees more power to walk, stand, sit and get up and down stairs.


At Real Life Prosthetics, Gerst is the first patient to use a Power Knee.

Jamin, whose practice is called Align Rehabilitation, now has three patients learning to use it.

Gerst’s achievement the other day occurred on an outdoor staircase. With his left hand on a railing and Jamin steadying him on the right, Gerst attempted to climb the stairs the way he did years ago, before his amputation.

That’s a simple movement most of us take for granted, but it has a term in physical therapy: “Step over step,” essentially one foot over the other.

“Normally,” says Jamin, “someone with an above knee amputation has to step onto stairs step-to-step, meaning two feet on one step each time. They have to step up with their non-prosthetic side.”

So Monday in the sunshine, Tony Gerst gave it a try. He planted his bionic right foot on a concrete step, and his bionic knee helped him up. At the same time, he swung his left leg to the next higher step, just like that, just as he did years ago, and Michelle Jamin made that happy sound.