OBJECTIVE -To compare the effectiveness of different types of footwear insoles in the diabetic neuropathic foot. RESEARCH DESIGN AND METHODS-A sample of 241 consecutive diabetic patients (158 men and 83 women, age 57.5 Ϯ 9.6 years [mean Ϯ SD], and mean duration of diabetes 12.3 Ϯ 7.2 years) attending the foot clinic with previous foot ulceration and those considered at high risk of foot ulceration were included in the study. The study groups consisted of group 1, patients provided with sandals with insoles made with microcellular rubber (n ϭ 100); group 2, with sandals with polyurethane foam (n ϭ 59); group 3, with molded insoles (n ϭ 32); and group 4, with their own footwear containing leather board insoles (n ϭ 50). Neuropathy status was assessed using a biothesiometer. Plantar pressure was measured using the RS Scan inshoe pressure measurement system. Data obtained from the metatarsal heads were used as the peak pressure. The state of the sandals was assessed after 9 months. The patients were considered to have had an ulcer relapse when either a new ulcer appeared at the site of a previous one or a new foot ulcer appeared in a different area.RESULTS -Patients who were using therapeutic footwear showed lower foot pressure (group 1, 6.9 Ϯ 3.6; group 2, 6.2 Ϯ 3.9; and group 3, 6.8 Ϯ 6.1 kPa; P ϭ 0.0001), while those who used the nontherapeutic footwear showed an increased foot pressure (group 4, 40.7 Ϯ 20.5 kPa; P ϭ 0.008). The occurrence of new lesions was significantly higher in patients in group 4 (33%) when compared with that of all other groups (4%).CONCLUSION -Therapeutic footwear is useful to reduce new ulceration and consequently the amputation rate in the diabetic population. Diabetes Care 27:474 -477, 2004D iabetic foot infection is a common cause for hospital admission among diabetic patients in India. This could be attributed to several sociocultural practices, such as walking barefoot, inadequate facilities for diabetes care, poor education, and poor socioeconomic conditions (1). It was reported earlier (2) that recurrence of foot infection was common among South Indian type 2 diabetic subjects and was related to the presence of peripheral vascular disease and neuropathy. A diabetic patient with a history of previous ulceration or amputation is at an increased risk for further ulceration, infection, and subsequent amputation. Alterations in foot dynamics due to ulceration, joint deformity, or amputation can cause abnormal distribution of plantar pressures and result in the formation of a new ulcer (3). In our earlier study (4), we reported that limited joint mobility and increased plantar pressure appear to be important determinants of foot ulceration irrespective of the duration of diabetes.The reduction of pressure peaks by providing special shoes turns out to be an effective tool for managing the neuropathic foot. Data from randomized trials on the usefulness of therapeutic footwear in preventing foot ulcers varies, with some studies showing benefits (5-7) and a few others not showing any benefic...

No abstract

Many foams and viscoelastic materials are used in shoes as insoles to replace the shock-absorbing and pressure distributing functions of natural fat pad beneath the foot that was lost due to some conditions such as diabetes, arthritis, age or overuse. In the present work, porous polyurethane sheets of 3-10 mm thickness based on segmented polyetherurethanes and polyesterurethane were developed by coagulation method. Sheets of different density, hardness and thickness were developed and tested for their mechanical and cushioning properties. The effect of concentration and composition of polymer and volume of solvent were studied and the required density, hardness and thickness of the sheets for application in therapeutic footwear were optimized from the test results.

It has been proved that polyurethane (PU) foam and viscoelastic PUs are offering better cushioning and shock absorption properties than other materials such as foam rubbers, polyethylene, ethylene vinyl acetate, and polyvinyl chloride which are used currently as insole materials in therapeutic footwear for diabetic and orthopedic patients to ''offload'' or redistribute high pressure under the foot. The aim of this research work was to prepare viscoelastic materials based on PUs having the highest degree of phase separation that provides for the elastomeric nature of these polymers. Polymer structures with a high concentration of amide groups can be made with the addition of hydrazine or a diacid hydrazide to a diisocyanate. We had prepared various PUs by chain extending the isocyanate-terminated prepolymer with terepthalic dihydrazide, 5-hydroxy isothalic dihydrazide, and 1,4-butanediol. Polymers were developed into sheets by phase inversion method using dimethyl formamide as solvent and water as nonsolvent. To improve the mechanical properties of PU sheets the polymer solution was blended with polyester-based PU Desmopan 8078 (CPU) in 1 : 1 ratio and the solution mixture was developed into sheet by the same method. Further PU sheets based on only CPU were also developed with various concentrations of PU. The synthesized PU and their blends with CPU were characterized by infrared spectroscopy, differential scanning calorimetry, thermo gravimetric analysis, gel permeation chromatography, and dynamic mechanical analysis. Morphological characteristics of PU sheets were studied by scanning electron microscopy.

No abstract