Shear and Pressure Reducing Insoles for the Diabetic Foot
Condition: Diabetes; Ulceration; Amputation; Foot Deformity; Neuropathy
MeSH terms: Foot Deformities; Foot Deformities, Congenital; Diabetic Foot
Study type: Interventional

Summary: 
      We evaluated the feasibility of the GlideSoft™ novel insole to reduce pressure and shear
      forces on the foot. No commercially available insoles are designed to reduce shear. Although
      insurance providers spend millions on diabetics' therapeutic insoles, there is no scientific
      data about shear or pressure reduction. We will evaluate the optimal bonded materials from
      Phase I compared to the Glidesoft™ design using the same combination of viscoelastic
      materials. We evaluate 2 patient groups of 150 patients per arm (300 total) in an 18 month
      trial. The control group patient arm wore a traditional bonded insole whereas another the
      second arm receive the GlideSoft™. At baseline, and at the end of the 18 month trial, in-shoe
      gait lab and in vitro biomechanical parameters measured pressure, shear, and material
      properties as these changed with wear. This Phase II eighteen (18) month clinical trial
      evaluated the effectiveness of ShearSole™ reducing the incidence of diabetic ulcers. The
      overall study hypothesis was that GlideSoft™ provides significant shear reduction as compared
      to traditional insoles without sacrificing pressure reduction characteristics or durability.
    

Detailed description: 
      1. To evaluate the efficacy of a shear reducing shoe insole (GlideSoft) in reducing the
           incidence of diabetic foot pathology among high-risk patients. We studied the
           effectiveness of a shear reducing shoe insole to prevent foot ulcers in high-risk
           diabetics with sensory neuropathy, a history of a foot ulcer or a history of a partial
           foot amputation. The study comprised two treatment arms. The first group received
           standard therapy involving standard therapeutic shoes and insoles, patient education and
           regular foot evaluations by a physician. The second group received the same standard
           therapy, but instead of the standard insoles patients used the GlideSoft - a novel shear
           reducing insole. As determined in the Phase I study, the GlideSoft dramatically reduced
           shear forces compared to standard insoles, while performing equally well in reducing
           compressive forces. Patients were followed for 18 months. The primary study outcome was
           for incident foot ulcers. Our hypothesis was that patients who use the GlideSoft will
           have fewer ulcers and that these ulcers will be less severe compared to patients
           evaluated in the Standard Insole Group.

        2. To evaluate changes in pressure and shear reducing capabilities of the two. To evaluate
           changes in pressure and shear reducing capabilities of the GlideSoft and standard
           insoles over the duration of use.

           We measured in-shoe pressures and in-vitro shear forces at the foot-insole interface at
           the beginning of the study and after patients wore the insole for four months or one
           "standard cycle of wear". We used the Novel Electronics, Inc. Pedar in-shoe pressure
           system to measure the interface between the foot and insole and the Shear Force Tester
           (see Phase I report) to evaluate shear forces. We expected that the GlideSoft would
           significantly reduce shear forces and provide equivalent reduction in vertical forces at
           both the day 0 evaluation and day 120 evaluations.

        3. To evaluate patient perceived benefits, satisfaction, and compliance with the 2. To
           evaluate changes in pressure and shear reducing capabilities of the GlideSoft and
           standard insoles over the duration of use.

      We measured in-shoe pressures and in-vitro shear forces at the foot-insole interface at the
      beginning of the study and after patients wore the insole for four months or one "standard
      cycle of wear". We used the Novel Electronics, Inc. Pedar in-shoe pressure system to measure
      the interface between the foot and insole and the Shear Force Tester (see Phase I report) to
      evaluate shear forces. We expected that the GlideSoft would significantly reduce shear forces
      and provide equivalent reduction in vertical forces at both the day 0 evaluation and day 120
      evaluations.
    

Intervention name(s): pressure reducing insole; GlideSoft®
Intervention type(s): Device; Device
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single
Primary purpose: Prevention
Keywords: friction; pressure; insole; ulcer; prevention