The effect of insoles in therapeutic footwear—A finite element approach

Lemmon, David R.; Shiang, Tzyy-Yuang; Hashmi, Azfar; Ulbrecht, Jan S.; Cavanagh, Peter R.

doi:10.1016/s0021-9290(97)00006-7

Cited by 212 publications

(138 citation statements)

References 13 publications

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“…The shape-pluspressure-based insoles (insole Z) used in the present study were ϳ2 and 4 mm thicker under the forefoot than shapebased insoles X and Y, respectively. Our previous studies have suggested that a reduction in plantar pressure of ϳ2-6 kPa/mm may be expected as insole thickness is increased (18), and thus thickness alone probably would not have accounted for the 43-and 78-kPa differences between shape-plus-pressure-based insole Z and shape-based insoles X and Y, respectively, seen in the flexible shoe condition. We believe many insole manufacturers do not fully exploit the available volume in the shoe under the midfoot and arch to use as a transfer area for MTH loads, and the shape-pluspressure-based insoles in the current study have emphasized use of this space (Fig.…”

Section: Discussionmentioning

confidence: 94%

Custom Therapeutic Insoles Based on Both Foot Shape and Plantar Pressure Measurement Provide Enhanced Pressure Relief

et al. 2008

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OBJECTIVE -The purpose of this study was to determine whether custom insoles tailored to contours of the barefoot pressure distribution and shape of a patient's foot can reduce plantar pressures in the metatarsal head (MTH) region to a greater extent than conventional custom insoles.RESEARCH DESIGN AND METHODS -Seventy regions of elevated barefoot pressures (mean peak 834 kPa under MTHs) were identified in 20 subjects with diabetes. Foam box impressions of their feet were sent to three different orthotic supply companies for fabrication of custom insoles. One company was also given plantar pressure data, which were incorporated into the insole design. Measurements of in-shoe plantar pressures were recorded during gait for the three custom insoles in a flexible and a rocker-bottom shoe. Peak pressure and force-time integral were extracted for analysis.RESULTS -In 64 of 70 regions, the shape-plus-pressure-based insole in the flexible shoe achieved superior unloading compared with the two shape-based insoles. On average, peak pressure was reduced by 32 and 21% (both P Յ 0.0001) and force-time integral by 40 and 34% (both P Ͻ 0.0001) compared with the shape-based insoles. At the midfoot, force-time integral was increased by 51 and 33% (both P Ͻ 0.01). Similar trends were found using the rockerbottom shoe.CONCLUSIONS -Compared with insoles based only on shape, the use of foot shape with barefoot plantar pressure measurements in designing custom insoles results in enhanced offloading of high-pressure areas under the forefoot. This offloading was achieved by a greater transfer of load to the midfoot without additional loading of other forefoot structures.

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Section: Discussionmentioning

confidence: 94%

Custom Therapeutic Insoles Based on Both Foot Shape and Plantar Pressure Measurement Provide Enhanced Pressure Relief

et al. 2008

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“…Although a number of other investigators have used finite element models to design orthotic devices [9][10][11][12][13], the work of Erdemir et al is most pertinent to this project [13]. Erdemir et al investigated the shape and size of an individual plug placed within the midsole of the shoe.…”

Section: Discussionmentioning

confidence: 99%

“…Research by other investigators include a partial 2D-model of the 2 nd metatarsal region of the foot to study the effect on plantar pressure due to changes in insole and tissue thickness [9]; a 3D-model of the standing foot to study the effect of flat and conforming insole of different materials in the plantar pressure distribution [10,11]; a 2D-model of the heel region of the foot to study the effect that shape, material properties and thickness of the insole have on PPP [12]; a similar partial model of the 2 nd metatarsal described by Lemmon et al [9] to investigate the effect of softer single plugs of different shapes penetrating the complete thickness of the shoe midsole [13].…”

Section: Introductionmentioning

confidence: 99%

Multi-plug insole design to reduce peak plantar pressure on the diabetic foot during walking

Actis

Ventura

Lott

et al. 2008

Med Biol Eng Comput

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There is evidence that appropriate footwear is an important factor in the prevention of foot pain in otherwise healthy people or foot ulcers in people with diabetes and peripheral neuropathy. A standard care for reducing forefoot plantar pressure is the utilization of orthotic devices such as total contact inserts (TCI) with therapeutic footwear. Most neuropathic ulcers occur under the metatarsal heads, and foot deformity combined with high localized plantar pressure, appear to be the most significant factors contributing to these ulcers. In this study, patient-specific finite element models of the second ray of the foot were developed to study the influence of TCI design on peak plantar pressure (PPP) under the metatarsal heads. A typical full contact insert was modified based on the results of finite element analyses, by inserting 4 mm diameter cylindrical plugs of softer material in the regions of high pressure. Validation of the numerical model was addressed by comparing the numerical results obtained by the finite element method with measured pressure distribution in the region of the metatarsal heads for a shoe and TCI condition. Two subjects, one with a history of forefoot pain and one with diabetes and peripheral neuropathy, were tested in the laboratory while wearing therapeutic shoes and customized inserts. The study showed that customized inserts with softer plugs distributed throughout the regions of high plantar pressure reduced the PPP over that of the TCI alone. This supports the outcome as predicted by the numerical model, without causing edge effects as reported by other investigators using different plug designs, and provides a greater degree of flexibility for customizing orthotic devices than current practice allows.

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“…Future investigations should examine applied pressures and ST strain in a three dimensional manner. Finite element models are one means investigators are pursuing to examine the three dimensional effect of pressure on the ST of the foot (Lemmon et al, 1997;Gefen et al, 2000;Jacob and Patil, 1999;Cheung et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

Effect of footwear and orthotic devices on stress reduction and soft tissue strain of the neuropathic foot

Lott

Hastings²,

Commean

et al. 2007

Clinical Biomechanics

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Background-Ground reaction forces from walking result in stress (pressure) and soft tissue strain at the plantar aspect of the foot. Excessive plantar pressure and tissue strain on the insensate foot may lead to ulceration. Our study investigated the effect of therapeutic footwear and custom-made orthotic inserts on pressure and tissue strain along the second ray of the plantar foot, and how these two variables are associated.Methods-Twenty subjects (mean age 57.3 [SD 9.3], 12 male, 8 female, body mass index 32.5 [SD 7.4]) with diabetes mellitus, peripheral neuropathy, and a history of a plantar ulcer participated. Plantar pressure data were recorded during computed tomography scans for four conditions (barefoot, shoe, shoe+total contact insert, and shoe+total contact insert+metatarsal pad). For each condition tested, tissue strain and plantar pressure were determined at the second metatarsal head and at 15 other points along the second ray. Intepretation-Footwear and orthotic devices tested in this study decreased pressure and soft tissue strain at the second ray of the foot, and these two variables were strongly related. A better understanding of the role tissue strain plays in distributing plantar forces may lead to improvements in the design of orthotic devices. Findings-Differences

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The effect of insoles in therapeutic footwear—A finite element approach

Cited by 212 publications

References 13 publications

Custom Therapeutic Insoles Based on Both Foot Shape and Plantar Pressure Measurement Provide Enhanced Pressure Relief

Custom Therapeutic Insoles Based on Both Foot Shape and Plantar Pressure Measurement Provide Enhanced Pressure Relief

Multi-plug insole design to reduce peak plantar pressure on the diabetic foot during walking

Effect of footwear and orthotic devices on stress reduction and soft tissue strain of the neuropathic foot

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