Kevin Johnson Puts a New Suspension System to the Test
February 2015 Issue
Before Kevin Johnson became a clinical trial test patient for a new suspension system that could improve comfort and mobility for people who use transfemoral prostheses, he used a lot of duct tape. It was the only way the Ohio native could keep his prosthesis on.
In 1979, Johnson was a teenager working on the family farm when he lost the lower portion of his right leg and part of his left foot after his shoestring became tangled in a combine and pulled him into the machine. He spent three months in the hospital, five months in recovery, and three years, including through high school, navigating on crutches.
"In the beginning, my skin was constantly breaking down and my socket was always full of blood. It was very painful, so it was a lot easier to get around on crutches," remembers Johnson, who says he's "49 and holding." The discomfort, however, did not stop him from resuming his old life after the accident. That meant getting back into farming, including operating the combine, and wrestling on his high school team. "I've never looked back [after the accident]," says Johnson, who has two grown children.
When he graduated from high school, Johnson says he realized that he wasn't going to have a good quality of life if he had to continue using crutches. Because his residual limb had many skin grafts, which caused pain and bled when he used a prosthesis, and because he had no leverage in the socket, he consulted with a prosthetist, and felt he would have greater options with a transfemoral-level amputation. After one surgeon refused to operate, Johnson and his mother found an orthopedic surgeon who was willing to amputate about four more inches of Johnson's leg, which removed all the scar tissue and skin grafts. "I was going from a below-the-knee amputee to becoming an above-the-knee amputee, so it was something I really had to think about," Johnson says.
He was 18 years old when he had the surgery in July 1983. One month later, Johnson says he was "ready to hit the ground running." He spent the next three years going through two more prosthetic limbs, trying to find one that would work well and be conducive with his active lifestyle. Johnson says that in 1988, his prosthetist at the time "broke the mold, literally," while making a new limb for him. That mold was the plaster cast used to pattern his socket, but the technicians glued it back together and fabricated a socket anyway. His prosthetist wanted to start over, but Johnson insisted on trying the new, albeit flawed, limb.
"Don't change a thing," Johnson remembers telling his prosthetist. "It fit perfectly and really allowed me to get on with my life."
For the next 20 or so years, Johnson-who owns a utility and excavating company that requires him to drive bulldozers and fly helicopters, and who has an affinity for driving monster trucks, roping cattle in rodeos, and racing motorcycles-wore that limb. When it would break, which it often did given Johnson's physically demanding work and his penchant for extreme sports, he purchased the parts out of his own pocket and did his own custom fabrication using a welding torch and duct tape.
Bye-Bye Duct Tape
By the end of 2007, Johnson's prosthesis had reached a point where even duct tape failed as a suitable repair material. A friend referred him to WillowWood, Mt. Sterling, Ohio, which Johnson thought was just another place to buy parts for his prosthesis. He didn't know that the company was about to change his life.
After a visit to WillowWood, he was told the company was not currently seeking test patients. "They asked me to fill out some paperwork and to check back with them in about a year," Johnson says. Five days later, however, Johnson received a call from company engineers asking him to return. "They said 'you do everything you're not supposed to do,' and wanted me to be a test patient," he says.
In February 2008, Johnson was accepted into WillowWood's test patient program and became one of about 20 patients for a new prosthetic technology program funded by the U.S. Department of Veterans Affairs (VA). WillowWood had begun working with the VA and the Lewis Stokes Cleveland VA Medical Center (VAMC) on new prosthetic technology for veterans with transfemoral amputations. The system is part of the VA's investment to improve prosthetic technology for military personnel, and now civilians such as Johnson benefit from a newly designed prosthetic system that uses elevated vacuum, intelligent controls, and phase change materials cooling technology.
According to William "Bill" Jones, BOCP, chief of Prosthetic and Sensory Aids Service, Cleveland VAMC, the ultimate goal of the program is to provide a secure and reliable fit and greater comfort for individuals with transfemoral amputations. "The range of comfort has improved tremendously," says Jones, who worked with five veterans as part of the testing phase for the suspension system. "The more comfort they feel, the longer they can wear their socket during the day, and the more comfortable they feel as a result, the more they can do for themselves."
Johnson was a good addition to the patient testing according to Jeff Denune, CP/L, WillowWood's clinical director of prosthetics and Johnson's prosthetist since he became part of the test program. "He's exactly what WillowWood was looking for," Denune says.
Denune says Johnson's role as a test patient is to provide WillowWood's development and testing department with feedback on test components.
"Kevin is a good thinker and has great mechanical skills," he says. "He's been known to break his previous prostheses. After he has broken them, he thinks of creative ways to keep things going."
Johnson was told by WillowWood employees to do whatever he could to push the prosthetic limbs he tested to their limits, and that is exactly what he has done. Since becoming a test patient, Denune says Johnson has yet to break a test prosthesis-but that's not from lack of trying.
Before becoming a tester for the suspension system, Johnson used his left foot when operating the accelerator on his cars, trucks, and the bulldozers for his business. Because his prosthesis was so loose, when he'd jump down from a heavy equipment machine, he used to let it fall to the ground and then lower himself and secure it back on. This is no longer the case.
"The vacuum system is great; it holds my leg in place," Johnson says. "Before, my leg used to fit like a loose shoe. It moved around a lot. Now the fit is so secure, I use my right leg for the accelerator. Now it fits so tight, it almost feels like it's a part of me." In fact, the socket fits so securely, Johnson says he can jump in the air and he doesn't have to worry about his leg coming off. "I haven't been able to do that in years," he says.
In addition to a better vacuum system, the new limb has been developed with other comfort factors in mind, including a new liner designed so that the user's residual limb will perspire less when wearing the prosthesis, Denune says. "The technology within the liner allows the limb to dissipate heat into the environment," he says. "As a result, the skin's healthier."
Johnson agrees. He says he has had little or no perspiration and skin irritation since he began wearing the prosthesis. "Before, I would have to dry out my liner four to five times a day," he says. "That's something I haven't had to do with this one."
No Going Back
Reports on the new system continue to be positive, according to Jones.
"These veterans now have greater range of motion," he says. "As a result, it has not only changed their lives, but those of their significant others because these amputees are increasingly able to do more and more for themselves."
Johnson agrees and says his association with WillowWood has been a fantastic partnership. "I give them my feedback on the positives and the flaws, and they listen," he says. "It's been a blessing that I can't brag on enough."
It wouldn't sit too well with him if he had to return to using his previous prosthetic leg. "They'd have to fight me for it," Johnson says. "I'd be out the door before they could grab me and get it off me."
Betta Ferrendelli is a freelance writer based in Denver, Colorado.