Bus SA, Ulbrecht JS, Cavanagh PR: Pressure relief and load redistribution by custom-made insoles in diabetic patients with neuropathy and foot deformity. Clin Biomech19: 629, 2004.10.1016/j.clinbiomech.2004.02.010)| false
Ibrahim M, El Hilaly R, Taher M, et al: A pilot study to assess the effectiveness of orthotic insoles on the reduction of plantar soft tissue strain. Clin Biomech28: 68, 2013.10.1016/j.clinbiomech.2012.09.003)| false
Kato H, Takada T, Kawamura T, et al: The reduction and redistribution of plantar pressures using foot orthoses in diabetic patients. Diabetes Res Clin Pract31: 115, 1996.879211010.1016/0168-8227(96)01214-4)| false
Owings TM, Woerner JL, Frampton JD, et al: Custom therapeutic insoles based on both foot shape and plantar pressure measurement provide enhanced pressure relief. Diabetes Care31: 839, 2008.1825289910.2337/dc07-2288)| false
Witana CP, Goonetilleke RS, Xiong S, et al: Effects of surface characteristics on the plantar shape of feet and subjects' perceived sensations. Appl Ergon40: 267, 2009.10.1016/j.apergo.2008.04.01418513701)| false
Xiong S, Goonetilleke RS, Zhao J, et al: Foot deformations under different load-bearing conditions and their relationships to stature and body weight. Anthropol Sci117: 77, 2009.10.1537/ase.070915)| false
Papuga MO, Burke JR: The reliability of the associate platinum digital foot scanner in measuring previously developed footprint characheristics: a technical note. J Manipulative Physiol Ther34: 114, 2011.
Papuga MO, Burke JR: The reliability of the associate platinum digital foot scanner in measuring previously developed footprint characheristics: a technical note. J Manipulative Physiol Ther34: 114, 2011.10.1016/j.jmpt.2010.12.008)| false
Paton J, Graham B, Jones R, et al: Effectiveness of insoles used for the prevention of ulceration in the neuropathic diabetic foot: a systematic review. J Diabetes Complication25: 52, 2011.10.1016/j.jdiacomp.2009.09.002)| false
Mohamed O, Cerny K, Rohek L, et al: The effects of Plastazote and Aliplast/Plastazote orthoses on plantar pressure in elderly persons with diabetic neuropathy. J Prosthet Orthot16: 55, 2004.10.1097/00008526-200404000-00005)| false
Accurate representation of the insole geometry is crucial for the development and performance evaluation of foot orthoses designed to redistribute plantar pressure, especially for diabetic patients.
Considering the limitations in the type of equipment and space available in clinical practices, this study adopted a simple portable three-dimensional (3-D) desktop scanner to evaluate the 3-D geometry of an orthotic insole and the corresponding deformities after the insole has been worn. The shape of the insole structure along horizontal cross sections is defined with 3-D scanning and image processing. Accompanied by an in-shoe pressure measurement system, plantar pressure distribution in four foot regions (hallux, metatarsal heads, midfoot, and heel) is analyzed and evaluated for insole deformity.
Insole deformities are quantified across the four foot regions. The hallux region tends to show the greatest changes in shape geometry (17%–50%) compared with the other foot regions after 2 months of insole wear. As a result of insole deformities, plantar peak pressures change considerably (–4.3% to +69.5%) during the course of treatment.
Changes in shape geometry of the insoles could be objectively quantified with 3-D scanning techniques and image processing. This investigation finds that, in general, the design of orthotic insoles may not be adequate for diabetic individuals with similar foot problems. The drastic changes in the insole shape geometry and cross-sectional areas during orthotic treatment may reduce insole fit and conformity. An inadequate insole design may also affect plantar pressure reduction. The approach proposed herein, therefore, allows for objective quantification of insole shape geometry, which results in effective and optimal orthotic treatment.
Corresponding author: Kit-lun Yick, PhD, Institute of Textiles and Clothing, ST735, The Hong Kong Polytechnic University, Hung Hum, Hong Kong, Hong Kong, Hong Kong. (E-mail: email@example.com).