In-shoe plantar pressure measurement technologies for the diabetic foot: A systematic review

Abstract

Introduction: Loss of cutaneous protective sensation and high plantar pressures increase the risk for diabetic foot patients. Trauma and ulceration are imminent threats, making assessment and monitoring essential. This systematic review aims to identify systems and technologies for measuring in-shoe plantar pressures, focusing on the at-risk diabetic foot population.

Methods: A systematic search was conducted across four electronic databases (Scopus, Web of Science, PubMed, Oxford Journals) using PRISMA methodology, covering articles published in English from 1979 to 2024. Only studies addressing systems or sensors exclusively measuring plantar pressures inside the shoe were included.

Results: A total of 87 studies using commercially available devices and 45 articles proposing new systems or sensors were reviewed. The prevailing market offerings consist mainly of instrumented insoles. Emerging technologies under development often feature configurations with four, six or eight resistive sensors strategically placed within removable insoles. Despite some variability due to the inherent heterogeneity of human gait, these devices assess plantar pressure, although they present significant differences between them in measurement results. Individuals with diabetic foot conditions appears exhibit elevated plantar pressures, with reported peak pressures reaching approximately 1000 kPa. The results also showed significant differences between the diabetic and non-diabetic groups.

Conclusion: Instrumented insoles, particularly those incorporating resistive sensor technology, dominate the field. Systems employing eight sensors at critical locations represent a pragmatic approach, although market options extend to systems with up to 960 sensors. Differences between devices can be a critical factor in measurement and highlights the importance of individualized patient assessment using consistent measurement devices.

Keywords: Diabetic foot; In-shoe systems; Instrumented insoles; Plantar pressure; Systematic review.

Fig. 1

Keywords used in the search for the selection of articles in the databases.

Fig. 2

Flow diagram of the selection of articles according to the PRISMA methodology.

Fig. 3

Predominant sensor technologies (A) and distribution of the most commonly used sensor configurations (B).

Fig. 4

Distribution of average plantar pressures between the non-diabetic and diabetic population through measurements with all devices (A) and between the group of author and market available devices with measurements from all participants (B). The studies do not present sufficient data for ML plantar location to compare author-devices vs. market-devices. Abbreviations: MH 1 - first metatarsal head, MH 2/3 - second/third metatarsal heads, MH 4/5 - fourth/fifth metatarsal heads, ML - midfoot lateral.

Fig. 5

Distribution of average plantar pressures of the non-diabetic population (A) and the diabetic population (B) both through measurements with author devices and those available on the market. The studies do not present sufficient data for ML plantar location to compare author-devices vs. market-devices. Abbreviations: MH 1 - first metatarsal head, MH 2/3 - second/third metatarsal heads, MH 4/5 - fourth/fifth metatarsal heads, ML - midfoot lateral.