Prosthetic Limb Advances Assist Amputees

“That’s where it all started was a wooden socket just like a pirate, you know, a peg leg.”

Kent Phillips is a certified and licensed prosthetist at Lubbock Artificial Limb and Brace. His father-in-law, Cecil McMorris, is a bilateral below-the-knee amputee from the Korean conflict and started the business in 1962. Phillips said prosthetic technology has changed vastly since he started working with the company in 1975.

Microprocessor technology has been developed to allow more natural movement in a prosthetic limb, and modern materials make wearing prostheses less tiring and more comfortable for an amputee.

“Back when I got in the field in ‘75,” Phillips said, “we were making plastic sockets, but we were setting them in wooden blocks, shaping them to look like a leg, and then covering it with plastic. Nowadays we use titanium, carbon – different components to make it as light as possible. Less energy is exerted, and it’s a whole lot easier on the patient.”

Phillips discussed the importance of fitting patients and making sure the prostheses does not rub sores or cause pain in the residual limb.

“The most common thing we see that they get in trouble with on the distal limb – any idea?” he said. “They don’t wear enough socks. Every patient wants to wear it too loose. It’s kind of like you wearing your shoes without socks, and you know you ought to have socks.”

Joan E. Sanders, Michael R. Severance, David L. Swartzendruber, Katheryn J. Allyn, and Marcia A. Ciol of the University of Washington in Seattle conducted a study in 2013 and wrote an article called, “Influence of prior activity on residual limb volume and shape measured using plaster casting: Results from individuals with transtibial limb loss.” The study consisted of 24 below-the-knee amputee participants, 17 males and seven females.

“Our results indicate that practitioners should be mindful of prior activity and doffing history when casting an individual’s limb for socket design and prosthetic fitting,” the authors said in the article. “In the present study, time between doffing and casting and order of testing affected cast volume.”

A prosthesis keeps the residual limb shrunken. If a prosthesis is fitted to the residual limb well, the prosthesis should fit snugly. Between doffing a prosthesis and casting a new one, the time should be limited, so the cast will stay the same size as the residual limb. If too much time passes, the cast will be larger and will not fit the patient as snugly as needed to prevent sores or injury.

Lacey Phipps, a senior biochemistry major from Ballycastle, Republic of Ireland, lifts up her pant leg to display one of two prosthetic legs with a tie-dye pattern melted into the plastic. She said her prosthetist from Washington, D.C., is one of the best. She is shadowing at Lubbock Artificial Limb and Brace because she hopes to become a prosthetist, too.

Phipps was born with bilateral clubfoot and made the decision to amputate her legs from the mid-calf down two years ago after many unsuccessful surgeries and spending the majority of her life in a wheelchair. She said doctors told her she would never walk, but she has now been walking for more than 14 months.

There are several causes of amputation. (Refer to Figure 1.) According to limb loss statistics on the Amputee Coalition website, about 185,000 amputations occur in the United States annually, and approximately 2 million Americans live with limb loss. The statistics also stated that over $8.3 billion of hospital costs were associated with amputation.

At 54 percent, vascular disease is the main cause of limb loss. This includes diabetes and peripheral arterial disease. The number of amputations due to diabetes is predicted to increase due to increasing obesity rates. (Refer to Figure 2.) Trauma is the next highest cause of amputation, at 45 percent, followed by cancer at less than two percent.

Darren Matsler, a senior communication design major from Lubbock, said the first thing he wonders about an amputee is how he or she lost a limb and adapts to that in life.

“I don’t know how I would live with it,” he said. “So, I figure every part of me is essential. I think it’s awesome. I think it shows you the strength we have to get over our, not necessarily disabilities, but our mental limitations that we might set on ourselves.”

Phipps’ below-the-knee prosthesis consists of a socket, pylon and foot. She said her feet are Ossur Variflex, which have a spring in the mechanics. The socket is custom fit and fits the leg to her body. The pylon is the metal “bone” of her leg, and the foot is like a regular foot allowing her to bear weight.

“So, it’s got some movement that kind of mimics an ankle,” Phipps said. “Yeah, that’s what my foot looks like. It walks essentially like your foot does.”

Walking is not all Phipps does. She is also a member of the Tech Irish Set Dancers. She described Irish set dance as being similar to a Texas square dance.

“As far as I know,” she said, “I’m the only bilateral amputee that does set dance. We haven’t ever been able to find another person that does it as an amputee.”

Phipps said she uses the same pair of feet for dancing and all other physical activities as she does for walking. The only times she’s had to change her legs have been on kayaking trips to allow herself to fit properly into the kayak.

“I do white water kayaking,” she said. “I do mountain biking. I do rock climbing. I do backpacking. I go hiking. I’m a bit of an adventure freak. I did a bicycle ride this summer 340 miles from Pittsburg to D.C. literally the week before I got back to class.”