Engineering Investment Aids Gel Liner Wearers

December 10, 2012

Contact: Lisa Watkins
1.800.848.4930 ext. 106

Engineering Investment Aids Gel Liner Wearers

After two years and numerous clinical trials, WillowWood is pleased to announce the latest advancement to Alpha® Liners. WillowWood has enhanced the gel used in its popular Alpha Liners to Advanced Formulas that improve performance while retaining comfort.

The Advanced Formulas have been in development for two years. Over 75 formulations of the gel were tested mechanically in order to identify the best candidate. Afterwards, with the help of 83 test patients internally and at beta sites, a full round of clinical testing was completed. Attributes of the Advanced Formulas tested include the rate at which gel migrates away from and returns to pressure points, biocompatibility, tensile strength, tear strength, durometer, peel strength, and elastic modulus. Comfort, while hard to quantify since it is subjective, was also gauged and rated by participating test patients.

Mechanical testing revealed a decrease in the gel migrating away from pressure points, which simulated high pressure areas or bony prominences on residual limb, compared to the previous gel formulations. Test patients with areas of high pressure within their sockets or bony prominences on their residual limbs confirmed these results. They noticed greater liner longevity while test patients without these issues continued to experience the same level of comfort and liner performance they were accustomed to with current Alpha Liners.

“Over the years, we’ve had numerous conversations with clinicians about how to improve Alpha Liners without detracting from their comfort or the skin-friendly nature of the mineral-oil and Vitamin E within the gel”, said Jeff Doddroe, New Product Development Director at WillowWood. “We take these conversations seriously and this improvement is founded in customer feedback. We started our quest to address liner durability and gel response time. We allowed ourselves time to extensively test various changes to the advanced formulas until we were 100% satisfied that the change would be positive for amputees and maintain the comfort they expect.”

When introduced in 1996 after 48 months of development and testing by inventor Bruce Kania and WillowWood, the revolutionary thermoplastic elastomer Alpha Liners were designed to comfortably protect residual limbs and skin from shear forces, abrasion, and breakdown. Sixteen years later the intent of Alpha Liners remains unchanged while the product line has experienced continuous improvements and expansion. For example,
– Initially offered in only one fabric and color, Alpha Liners are now offered in four different fabrics, each with its own features and benefits, and four different colors.
– Three additional gel profiles (AK, symmetrical, and progressive), developed for optimal fit and comfort, joined the initial profile options of uniform, tapered and contoured profiles.
– The thread and stitching methods used in Alpha Liners have evolved over the years to improve liner longevity and comfort.

Starting January 1, 2013, WillowWood will begin transitioning to shipping Alpha Liners and Sleeves that contain the Advanced Formulas in both Classic and Hybrid variants. Mineral oil and Vitamin E remain key components of the proprietary Advanced Formulas. Both prefabricated liners and custom Alpha DESIGN® Liners will utilize the Advanced Formulas. Sizing of the liners is unchanged and Alpha Liners will continue to have a 30-day trial period and 12-month warranty.

WillowWood, located in Mt. Sterling, Ohio, is an industry leader in the design, manufacturing, and distribution of prosthetic products, including LimbLogic®, the Fusion™ Foot, and the OMEGA® CAD system. For more information about WillowWood and its products, please call 1.800.848.4930 or visit the company website

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