Footwear and insole design features for offloading the diabetic at risk foot—A systematic review and meta‐analyses

Abstract

The aim of this systematic review was to identify the best footwear and insole design features for offloading the plantar surface of the foot to prevent foot ulceration in people with diabetic peripheral neuropathy. We searched multiple databases for published and unpublished studies reporting offloading footwear and insoles for people with diabetic neuropathy and nonulcerated feet. Primary outcome was foot ulcer incidence; other outcome measures considered were any standardized kinetic or kinematic measure indicating loading or offloading the plantar foot. Fifty‐four studies, including randomized controlled studies, cohort studies, case‐series, and a case‐controlled and cross‐sectional study were included. Three meta‐analyses were conducted and random‐effects modelling found peak plantar pressure reduction of arch profile (37 kPa (MD, −37.5; 95% CI, −72.29 to −3.61; P < .03), metatarsal addition (35.96 kPa (MD, −35.96; 95% CI, −57.33 to −14.60; P < .001) and pressure informed design 75.4 kPa (MD, −75.4 kPa; 95% CI, −127.4 to −23.44 kPa; P < .004).The remaining data were presented in a narrative form due to heterogeneity. This review highlights the difficulty in differentiating the effect of different insole and footwear features in offloading the neuropathic diabetic foot. However, arch profiles, metatarsal additions and apertures are effective in reducing plantar pressure. The use of pressure analysis to enhance the effectiveness of the design of footwear and insoles, particularly through modification, is recommended.

Data-driven CAD-CAM vs traditional total contact custom insoles: A novel quantitative-statistical framework for the evaluation of insoles offloading performance in diabetic foot

“…A recent review of Collings et al 2020 [ 17 ] highlighted the difficulty in differentiating the effect of the different insole and footwear features in offloading the NDF. However, they found that arch profiles, metatarsal additions, and apertures are effective in reducing plantar pressure.…”

“…Foot orthotics are mostly evaluated based on clinical experience and a trial-and-error approach [ 11 ]. Conversely, studies introducing the routinely use of quantitative plantar pressure measurement-driven directions for effectively offloading insoles are increasingly presented in the literature [ 2 , 3 , 7 , 5 , 8 – 14 , 17 ]. Several studies have investigated the offloading effects either induced by elevating pressures in areas of lower pressure (e.g.…”

“…medial arch support and metatarsal pads or bar) [ 3 , 9 – 11 , 18 – 20 ] or by the use of soft materials in areas of high pressure (e.g. forefoot cushion) [ 21 ] or the combination of the two [ 12 , 17 ]. In these studies, various optimisation strategies have been presented to find the "optimal offloading design".…”

“…In these studies, various optimisation strategies have been presented to find the "optimal offloading design". They are based on the 3D shape, and plantar pressure distributions information either used singularly (for total contact insoles) [ 13 , 22 , 23 ] or in some combined way [ 3 , 8 , 9 , 11 , 17 , 24 , 25 ]. Plantar pressure can be redistributed but not eradicated and reducing stress at one location may simply displace the risk of ulceration to a different area of the foot [ 12 ].…”

“…In any case, in the absence of other proven thresholds, the 200kPa limit is taken as a standard reference. Although these custom-made insole-design approaches significantly reduce plantar foot pressure, their effects have been studied in small groups of participants and outcomes are variable across patients [ 17 , 18 , 20 , 22 ], even if controlled clinical trials are increasingly presented in the literature [ 2 , 6 , 15 , 28 ]. To guarantee the best as possible offloading performance along time, a well-established periodic systematic control to verify and eventually modify/correct insoles’ characteristics has to be set [ 3 , 11 ].…”