The effect of insole configurations on plantar pressure in diabetic patients with neuropathic feet

The effect of insole configurations on plantar pressure in diabetic patients with neuropathic feet

Abstracts / Clinical Biomechanics 23 (2008) 662–720 Table 1 Bare forefoot plantar peak pressure (kPa) Region BT MT-1 MT-2 MT-3 MT-4 MT-5 * ** PNP (...

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Abstracts / Clinical Biomechanics 23 (2008) 662–720 Table 1 Bare forefoot plantar peak pressure (kPa) Region

BT MT-1 MT-2 MT-3 MT-4 MT-5 * **

PNP

(106 feet)

PNP+ (80 feet)

Mean

SD

Min–Max

Mean

SD

Min–Max

455 308 475 429 288 224

264 138 226 168 102 147

81–1180 90–801 160–1210 187–1120 140–660 70–782

405 481** 551 462 311 312*

257 313 271 202 149 238

24–10 132–1260 199–1220 152–1000 125–1020 66–1060

PNP versus PNP + P < 0.05. P < 0.005.

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The effect of insole configurations on plantar pressure in diabetic patients with neuropathic feet Nick A. Guldemond a, Geert HIM Walenkamp a, Pieter Leffers b, Fred Nieman c a

Department of Orthopaedic Surgery, University Hospital Maastricht, The Netherlands b Department of Epidemiology, Faculty of Medicine, Maastricht University, The Netherlands c Clinical Epidemiology and Medical Technology Assessment. University Hospital Maastricht, The Netherlands

Introduction Table 2 Summary of multiple regression models Region

Model

R

R2

BT

Clinical Radiological Comprehensive

0.54 0.51 0.37

0.29 0.26 0.14

3.927 0.128 0.175

0.185 0.708 0.704

MT-1

Clinical Radiological Comprehensive

0.62 0.22 0.62

0.39 0.19 0.39

3.103 3.751 4.014

0.058 0.353 0.206

MT-2

Clinical Radiological Comprehensive

0.46 0.42 0.58

0.22 0.18 0.33

3.311 2.771 2.645

0.156 0.263 0.244

MT-3

Clinical Radiological Comprehensive

0.35 0.40 0.46

0.12 0.16 0.21

3.251 3.139 2.795

0.137 0.245 0.206

MT-4

Clinical Radiological Comprehensive

0.30 0.25 0.35

0.09 0.06 0.13

3.017 2.03 2.026

0.131 0.371 0.359

MT-5

Clinical Radiological Comprehensive

0.47 0.46 0.57

0.22 0.21 0.33

3.096 1.448 1.837

0.201 0.596 0.564

SE

b

All P-values for the overall analyses were <.0001, except for the clinical and radiological models of MT-4 region: >.05. The P-value of each particular b coefficient was below .05.

(Table 2). Callus formation and toe deformity were identified as relevant clinical predictors for all regions. The radiological models explained up to 26% of variance with a maximum of seven predictors. For most regions the combination of clinical and radiological predictors resulted in the largest explained variance. Conclusion At best, clinical and radiological measurements could explain 40% local barefoot peak pressures in diabetic patients. The results of this study suggest that there is merit in quantitative plantar pressure measurement for standard diabetic foot care. doi:10.1016/j.clinbiomech.2008.03.051

Foot orthoses are widely prescribed in an attempt to decrease elevated plantar pressures in areas of actual or potential ulceration at the shoe–foot interface. The objective of this study was to evaluate the effects of a metatarsal dome, a varus and a valgus wedge and two arch supports on plantar pressures in patients with diabetic neuropathy. Methods Seventeen male diabetic patients with peripheral neuropathy and elevated barefoot plantar pressure were selected from an outpatient clinic. The insoles were tailor-made following standardized construction procedures and using identical materials. Two arch ‘inserts’ could be placed on the basic insole, resulting in three support heights: no support (basic insole), standard support and extra support, whereas the standard and the extra support were, respectively, 5 and 10 mm higher than the basic insole. For the dome condition, a standard manufactured metatarsal dome was positioned on the basic insole. Full-length 5° varus and valgus ‘posts’ or ‘wedges’ made of cork were placed underneath the basic insole. Eleven insole configurations were compared with the basic insole. All insole configurations were evaluated with the Pedar Insole-systemÒ (Novel, Munich), while patients walked on a treadmill in standard socks and oxford type shoes. Peak pressure was calculated for the big toe, the lateral, central and medial forefoot regions. For each region, the highest peak pressure measured during the baseline condition (basic insole) was used to calculate the difference between the experimental conditions. A four-way within-factor repeated measures ANOVA design was used for the analysis of the plantar pressure data. Results In the lateral region, only the effect of a metatarsal dome was statistically significant (P < .001). For the central forefoot region, the effects of a metatarsal dome standard and extra arch support were statistically significant (P < .001).

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Abstracts / Clinical Biomechanics 23 (2008) 662–720

This was also true for the effects on in the medial forefoot region. There were no statistically significant effects of the insole configurations in the big toe region (P > .224), with an exception of the combination of the extra arch support and a varus wedge (P < .017). The highest reductions were accomplished with an extra arch support in combination with a metatarsal dome. The reductions achieved with a combination of components were not attributable to an interaction effect, but an additive effect of the independent components. The effects of the insole components in the lateral and big toe regions were small. Both varus and valgus wedges resulted in minor effects. The variation of the plantar pressure data in the big toe region points toward the specific individual responses in this region. Conclusion For non-deformed flexible neuropathic feet, the greatest effects on peak pressure reductions were achieved in the central and medial forefoot regions through application of a metatarsal dome and an (extra) arch support. Means and standard deviations of peak pressures, averaged over left and right feet

a

Doctoral Program in Physical Therapy, US Army-Baylor University, TX, USA b Department of Physical Therapy, Northern Arizona University, AZ, USA

Background Static arch height extremes have been associated with increased risk for overuse injury (Kaufman et al., 1999; Williams and McClay, 2001). However, the influence of running shoe type on plantar pressure distributions or mean contact areas across either the planus or the cavus foot during gait remains unknown. The primary purpose of this study was to analyze differences in plantar pressure and mean contact area between individuals with pes planus or pes cavus feet across three shod conditions. A secondary purpose was to determine the association between the static arch height index (AHI; Williams and McClay, 2000) and the dynamic modified arch index (MAI; Cavanagh, 1987). Methods Subjects

Basic

Standard support

Extra support

Lateral Basic Varus Valgus Dome

13.5 ± 4.32 13.5 ± 3.71 13.2 ± 3.56 12.1 ± 4.00

13.8 ± 4.35 14.1 ± 4.02 13.4 ± 3.99 12.4 ± 3.98

13.6 ± 3.98 13.3 ± 3.58 13.0 ± 3.70 12.3 ± 3.86

Central Basic Varus Valgus Dome

As part of a larger study, 543 subjects were screened using the AHI. Seventy-five subjects were identified as having pes planus (n = 40; AHI < .306) or pes cavus (n = 35; AHI > .386) based on their AHI values being 1.5 standard deviations above or below the group mean.

21.0 ± 5.84 20.6 ± 4.33 20.6 ± 6.64 17.2 ± 6.71

19.0 ± 6.16 18.8 ± 5.08 18.6 ± 5.75 16.3 ± 6.04

16.4 ± 6.35 15.4 ± 7.00 16.2 ± 6.52 12.8 ± 6.68

Methods

Medial Basic Varus Valgus Dome

23.1 ± 5.89 22.5 ± 5.72 22.6 ± 6.87 18.7 ± 5.82

21.6 ± 5.08 21.1 ± 4.65 21.7 ± 5.45 17.7 ± 5.32

19.2 ± 5.30 17.8 ± 5.26 19.1 ± 5.28 15.0 ± 6.50

Big toe Basic Varus Valgus Dome

18.5 ± 8.38 18.2 ± 7.84 17.0 ± 7.75 17.0 ± 10.2

18.1 ± 9.65 17.0 ± 9.53 16.9 ± 7.51 18.0 ± 11.1

17.0 ± 9.27 14.6 ± 9.81 17.1 ± 9.77 16.5 ± 10.22

Basic conditions are outlined and bold printed.

doi:10.1016/j.clinbiomech.2008.03.052

Influence of running shoe type on distribution and magnitude of plantar pressures among those with pes planus or pes cavus feet Joseph M. Molloy a, Nancy S. Yeykal a, Bradley S. Tragord a, Matthew S. Neal a, Eric S. Nelson a, Douglas S. Christie a, Deydre S. Teyhen a, Thomas M. McPoil b

Capacitive pressure-sensing insoles (PedarÒ, Novel Electronics Inc., Munich, Germany) were secured to the subjects’ feet with anti-embolism stockings (Burnfield et al., 2004). Subjects walked on a treadmill at 3.0 mph under three shod conditions (non-shod, motion-control, and cushioning running shoes). Data analysis Mean contact area and mean plantar pressure of the forefoot, midfoot, and rearfoot were determined over a 10-step period. MAI was calculated by dividing the mean plantar contact area of the midfoot by the entire mean plantar contact area. Modified Pressure Index (MPI) was calculated using the same equation, but substituting mean contact pressure for area values. A 2  3 mixed model repeated measures ANOVA (a = .05) was performed for each dependent measure (MAI and MPI). Independent variables were arch type (pes planus and cavus) and condition (non-shod, motioncontrol and cushioning running shoes). To determine