Material considerations expand footwear options

[Guest guest]

Material considerations expand footwear options

Patient's desire for choice and practioners' desire for reimbursement

often drive manufacturing changes.

By: Lori Rochelle Roniger

http://biomech.com/showArticle.jhtml?articleID=180100020

The materials used in diabetic footwear have been going high-tech,

mirroring trends in other specialty clothing and shoes.

Diabetic footwear manufacturers are incorporating stretchy materials

like neoprene and Lycra that allow footwear to better accommodate

feet with edema or deformities. They've also begun featuring X-

Static, a silver-containing material purported to have antimicrobial

and thermoconductive properties.

Shoe styles have evolved, too, so that many of the models look more

like regular shoes, although current products are not yet ready to be

called fashion forward. But that doesn't change the fact that for

many diabetic patients, the necessity of wearing specialized footwear

makes them feel like children who are forced to eat their vegetables:

They know it's good for their health but they just don't like it.

" Baby boomers are looking for more stylish shoes-everyone is, " said

Ross Marty, CO, CPed, who used to operate his own practice and is now

Acor's director of clinical education, about his many patients in

this age group. " But you need to have a shoe that's functional first.

You can worry about the style later. "

He said these individuals tend to be Internet-savvy. They research

their problems and ask more questions than the typical patient,

requiring that medical practitioners provide more educational

information on footwear. But it also offers an opportunity to explain

the functional reasons behind the way a shoe is constructed and

styled.

Stretch it out

Shoes containing stretchy materials can be helpful for diabetic

patients with edema, as well as for individuals with other foot

deformities, either unilateral or bilateral, said Bob Toth, CPed.

Toth works with patients at Boas Surgical in town, PA, and is

also a consultant for footwear manufacturer Pedors.

" They work well for a diverse population of patients, " Toth said.

He noted that shoes made with stretch features in different areas can

accommodate a brace worn unilaterally, such as a molded ankle foot

orthosis (MAFO), or deformities, such as hammertoes or bunions,

without requiring a bigger shoe width, a larger shoe size for one

foot-which usually requires buying one and a half or two pairs of

shoes-or a custom shoe.

" If not for stretchy materials, these patients would have to have

shoes made, " Toth said.

And having custom shoes made, which can be a necessity for those with

foot deformities that can't be accommodated by other shoes, isn't

cheap. The cost can start at $200 and run more than $1000. Branier

Orthopedic Custom Molded Shoes' products typically are at least $550

for a basic blucher-style lace-up model, with other styles, like

boots, and other features, like heavy-duty deerskin, costing more.

Toth also noted that stretchy materials allow more margin of error

for inexperienced fitters. And he explained that shoes made with

stretchy materials provide greater softness and less pressure on the

feet of diabetic patients with edema than more traditional leather

shoes, which are more likely to rub against the feet and cause skin

abrasion.

The first shoes Pedors offered in 1997 contained neoprene. These

models, as well as one premiered later, are ideal for diabetic

patients, particularly those with problems such as edema, peripheral

neuropathy, and rheumatoid arthritis, according to O'Hare,

the company's president and cofounder. O'Hare and his brother, ,

created the company in 1995, immediately setting to work on

researching and developing stretch shoes.

O'Hare said he prefers neoprene to Lycra or other types of

spandex because it offers a greater degree of support and has an

aesthetically pleasing tendency to revert back to its original shape.

Pedors' stretch shoes also are lightweight and machine-washable,

features that can be especially helpful for patients in long-term

care facilities, some of whom have only limited mobility and are

incontinent. The company is currently studying other potential

stretch materials and materials thought to increase air flow in shoes

and boost vascular activity in people with diabetes, O'Hare said.

Footwear manufacturer Aetrex Worldwide falls into the Lycra camp,

using the material predominantly in the forefoot in the company's

shoes for people with diabetes. Because of the added flexibility in

the toe area, some of the company's shoes are well-suited for

diabetic patients with foot deformities like hammertoes and bunions,

said Glenn Strickman, Aetrex's vice president of sales.

Some of the company's shoes are also lined with plastazote, a closed

cell polyethylene foam, which allows the footwear to mold to the

foot, Strickman said.

Silver mining

Diabetic patients nowadays have multiple opportunities to encounter

silver, which is used in footwear specifically designed for the foot

problems they typically face, as well as in silver-coated dressings

used for healing chronic wounds.

X-Static, which is manufactured by Noble Fiber Technologies, is

licensed for use in shoes, socks, and orthoses for individuals with

diabetes and other foot problems and in other products like athletic

clothing and bandages. Since 2004, the lining of Acor's shoes, which

are designed for people with diabetes and other foot problems, have

contained X-Static. The topcover of Acor's Sole Defense orthoses,

which are worn by diabetic patients, also contains the silver

product, as does TheraSock's SmartKnit Silver seamless diabetic sock,

manufactured by Knit-Rite.

" Having silver against the skin reduces the chance of infection, "

Marty said.

A number of studies on the antimicrobial properties of silver have

been conducted. Researchers reported in Antimicrobial Agents and

Chemotherapy in January 1987, that the survival of bacteria, such as

Escherichia coli, Klebsiella, Pseudomonas, Staphylococcus, and

Streptococcus decreased when exposed to X-Static, with the bacterial

death rate increasing as silver ion concentration increased.

Another study published in 1987, and also conducted by Penn State

University researchers, found that wearing silver-containing foot

orthoses significantly decreased the number of microorganisms present

in the foot and led to a reduction in odor compared to wearing

orthoses without the element. For seven days, nine study subjects

wore shoes with Dr. Scholl's Double Comfort Insoles.

A lightweight cloth woven with silver-coated thread was pressure-

laminated to the bottom of the insole in the right shoe. In the left

(control) shoe, the same insole had a cloth of the same weight that

did not contain silver pressure-laminated to its bottom.

The investigators found that the number of microorganisms in the

shoes with the experimental orthoses decreased by an average of 88%

and in the control shoes increased by an average of 12%.

Additionally, a subjective test of the shoes at the end of the study

found that the ones with the silver-containing cloth attached to the

orthoses smelled less than the control shoes.

Marty recommends silver-containing footwear for high-risk patients

with elevated chances of ulceration and for those who perspire

heavily. In addition to its other qualities, silver is believed to

have thermoconductive properties, he said, allowing heat to be

transferred away from a blister or other wound, lessening the chance

that it will worsen.

Audree Lezniewicz, CPed, a clinical specialist at Acor, noted that

wearing footwear lined with a silver-containing fabric, as well as

orthoses and socks including the metal, is helpful for

immunocompromised patients.

" Anything you can do to reduce the possibility of any kind of

bacterial or fungal infection is beneficial to the diabetic patient, "

she said.

A reduction in foot edema has been anecdotally observed in those who

wear shoes containing X-Static. Diabetic footwear customers have more

interest in edema nowadays, Marty noted, since with more of them

conducting personal medical research, they are more frequently self-

diagnosing the problem. He recommended that patients with edema wear

shoes with two liners, one of which can be removed later in the day

to provide more depth if they experience swelling.

Pour it on

Orthoses are also seeing their share of technological improvements.

For high-risk diabetic patients, Toth likes to use prefabricated heat-

moldable trilaminated orthoses that contain microcellular urethane

foam. He has designed such a product for Pedors, which is similar to

the custom-made orthoses he constructs for some of his own patients.

Trilaminates that contain Poron or other microcellular urethane foam

products are more spongy and provide better relief to high-pressure

areas over time than bilaminates without the substance, according to

Toth.

Foto, CPed, a biomedical research engineer at the Baton Rouge,

LA-based National Hansen's Disease Programs, which is part of the

U.S. Department of Health and Human Services, published a study in

the December 1998 issue of Foot & Ankle International that compared

various multidensity orthotic material combinations. His research

found that a polyurethane product like Poron in combination with

plastazote, which is thermomoldable, yielded the best performance

after more than 100,000 cycles in a dynamic compression device.

" We saw that polyurethane is the champion, " Foto said.

Additionally, he noted that a firm-density plastazote-polyurethane

combination held up better in response to repetitive stress than

medium-density plastazote. Foto studied these products in part

because Medicare reimburses orthoses that are custom-molded and

multidensity.

But there's more than one way to make an orthosis for diabetic

patients. Prime Materials' Treadeasy Footcare Products uses its own

brand of plastazote, Primolene, which became available in 2005 and

for which Medicare's Therapeutic Shoe Bill provides reimbursement, as

a top layer for its trilaminate foot orthoses.

" It doesn't bottom out as quickly as some products, " Prime Materials

president Drew Gallacher said of Primolene.

Prime Materials makes approximately 80% of the materials it uses in

its Treadeasy orthoses. Materials manufactured by the firm are also

purchased by other foot product companies, as well as firms in such

industries as aerospace and automobile production.

Gallacher said Primolene is cheaper than other plastazotes.

It is composed of relatively small cells, which is preferable to

larger-cell products, as they may have more air bubbles and a rougher

texture. He said it is ideal for providing total contact for the foot

and that areas where minimal pressure is exerted, such as under the

arches and toes, don't compress.

Gallacher also touts Prime Materials' polyurethane product, Celon,

which has been available since 2004 and serves as a middle layer for

Treadeasy orthoses. Prime Materials promotes Celon, made from a blend

of multiple ethylene vinyl acetate and rubber materials, for its

rebound qualities. But it is not moldable, leaving that task to other

orthotic layers and materials. EVA provides the bottom layer for

Treadeasy orthoses.

Molding the future

Foto plans to study how silver-containing orthoses handle mechanical

stress. Trained as a mechanical engineer, he strives to provide

objective information on generic materials used in diabetic footwear

to guide practitioners and companies in crafting therapeutic products

and solutions for patients.

However, his research will not look at other characteristics, such as

moisture and bacteria control, that Noble Fiber Technologies

attributes to X-Static and products in which it is used. Foto sees

the ability to withstand mechanical stress as the key attribute of an

orthosis for someone with diabetes. And as a federal government

employee, he wants to ensure that a diabetic orthosis, of which

Medicare will pay for three per year per patient, will work well for

four months.

Prime Materials may begin manufacturing more rigid materials to be

used in orthoses at some point, although Gallacher said they will be

most appropriate for athletes and people in need of foot alignment

corrections and not people with diabetes.

Meanwhile, other diabetic shoe and orthosis manufacturers continue to

study the properties of materials that haven't previously been

incorporated in such footwear. While many of them prefer to remain

quiet about the specific materials and their qualities, fearing their

plans may be poached by competitors, look for the inclusion of new

materials in diabetic footwear products as soon as this year.

" Upcoming products will take diabetic footwear to another level, "

Toth said.