Volume 41 Number
6A, November/December 2004
Pages 767 — 774
Effectiveness of insoles on plantar pressure redistribution
Bonnie Yuk San Tsung, MPhil; Ming Zhang, PhD; Arthur Fuk Tat Mak, PhD; Margaret Wan Nar Wong, FRCS
Jockey Club Rehabilitation Engineering Centre, The Hong Kong Polytechnic University, Hong Kong, China;
Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
Abstract-For this study, we compared the effectiveness of different design insoles for redistributing pressure during walking for diabetic patients and for normal control subjects. Comparisons of dynamic plantar foot pressure patterns were made with different support, including shoe-only, flat insole, and three contoured insoles. We custom-molded the three contoured insoles by casting the plantar surface of the foot under the conditions of non-weight-bearing, semi-weight-bearing, and full-weight-bearing. With the F-Scan in-shoe system, the interfacial pressure distribution during walking with different plantar supports was measured at 50 Hz for 10 s. The use of insoles could significantly reduce local peak pressure and pressure-time integral and increase the contact area. Contoured insoles were significantly better than flat insoles with regard to the insole functions in reducing local peak pressures. The insole with the semi-weight-bearing foot shape can offer the greatest peak pressure reduction compared to other insole designs, especially for patients with peak pressure located at the second to third metatarsal heads.
Key words: diabetes mellitus, foot biomechanics, foot pathologies, foot shape, insole design, neuropathy, plantar pressure.