Study on the foot shape characteristics of the elderly in China

Prevalence and Clinical Factors Associated With Pes Planus Among Children and Adults: A Population-Based Synthesis and Systematic Review

Estimates of pes planus ("flatfoot") prevalence vary considerably across studies. Moreover, there is uncertainty over which factors are associated with the pes planus prevalence. We aimed to systematically review the prevalence and clinical factors associated with flatfoot among children and adults. We searched Web of Science, PubMed/MEDLINE, and Google Scholar databases reporting population-based flatfoot prevalence. Two reviewers independently extracted the data and assessed the qualities of the studies. Subgroup analysis was conducted to analyze the associated factors on flatfoot prevalence. Frequencies, odds ratios (OR), and 95% confidence intervals (CI) were performed using descriptive analysis and chi-square test accounting for heterogeneity. Any conflict in the data analysis was discussed by all the reviewers. Twelve studies including 2509 flatfoot cases were analyzed (overall prevalence 15.6%, n = 16,000). The subgroup analysis indicated that male gender (OR = 1.26, 95% CI: 1.15-1.37), age groups 3 to 5 years (OR = 2.02, 95% CI: 1.78-2.30) and 11 to 17 years (OR = 1.91, 95% CI: 1.64-2.22), Asian race (OR = 2.34, 95% CI: 2.10-2.60), and obesity (OR = 2.62, 95% CI: 2.06-3.32) were more associated with flatfoot (p < .001). Conversely, female gender (OR = 0.44, 95% CI: 0.40-0.48) and White race (OR = 0.52, 95% CI: 0.47-0.57) were less associated with flatfoot (p < .001). Our findings may be valuable for clinical/surgical settings, particularly, for those modifiable findings and targeted populations. However, we suggest that future studies estimating flatfoot should consider prospective/multicenter designs using a common screening methods in random samples populations.

A Three-Dimensional Printed Foot Orthosis for Flexible Flatfoot: An Exploratory Biomechanical Study on Arch Support Reinforcement and Undercut

The advancement of 3D printing and scanning technology enables the digitalization and customization of foot orthosis with better accuracy. However, customized insoles require rectification to direct control and/or correct foot deformity, particularly flatfoot. In this exploratory study, we aimed at two design rectification features (arch stiffness and arch height) using three sets of customized 3D-printed arch support insoles (R+U+, R+U-, and R-U+). The arch support stiffness could be with or without reinforcement (R+/-) and the arch height may or may not have an additional elevation, undercutting (U+/-), which were compared to the control (no insole). Ten collegiate participants (four males and six females) with flexible flatfoot were recruited for gait analysis on foot kinematics, vertical ground reaction force, and plantar pressure parameters. A randomized crossover trial was conducted on the four conditions and analyzed using the Friedman test with pairwise Wilcoxon signed-rank test. Compared to the control, there were significant increases in peak ankle dorsiflexion and peak pressure at the medial midfoot region, accompanied by a significant reduction in peak pressure at the hindfoot region for the insole conditions. In addition, the insoles tended to control hindfoot eversion and forefoot abduction though the effects were not significant. An insole with stronger support features (R+U+) did not necessarily produce more favorable outcomes, probably due to over-cutting or impingement. The outcome of this study provides additional data to assist the design rectification process. Future studies should consider a larger sample size with stratified flatfoot features and covariating ankle flexibility while incorporating more design features, particularly medial insole postings.

Can Insoles Be Used to Improve Static and Dynamic Balance of Community-Dwelling Older Adults? A Systematic Review on Recent Advances and Future Perspectives

This systematic review investigated the effects of orthopedic, vibrating, and textured insoles on the postural balance of community-dwelling older adults. Articles published in English from 1999 to 2019 investigating the effects of (a) orthopedic, (b) vibrating, and (c) textured insoles on static and dynamic balance in community-dwelling older adults were considered. Twenty-four trials with a total of 634 older adults were identified. The information gathered generally supported the balance-improving effects of orthopedic, vibrating, and textured insoles in both static and dynamic conditions among community-dwelling older adults. Further examination found that rigidity, texture patterns, vibration thresholds, and components like arch supports and heel cups are important factors in determining whether insoles can improve balance. This review highlights the potential of insoles for improving the static and dynamic balance of community-dwelling older adults. Good knowledge in insole designs and an understanding of medical conditions of older adults are required when attempts are made to improve postural balance using insoles.

Effect of 3D Printing Individualized Ankle-Foot Orthosis on Plantar Biomechanics and Pain in Patients with Plantar Fasciitis: A Randomized Controlled Trial

BACKGROUND Traditional ankle-foot orthoses (AFOs) are not effective in treating plantar fasciitis, while customized 3-dimensional (3D) printed ankle-foot orthoses are effective in treating many ankle-foot diseases. This study investigated the effects of customized 3D printed AFOs on biomechanics and comfort of the plantar foot in plantar fasciitis. MATERIAL AND METHODS Sixty patients with bilateral plantar fasciitis aged 31-60 years participated in this study. At week 0, patients were randomly assigned into 2 groups: the control group consisting of those wearing separate shoes with prefabricated AFOs; and the experimental group consisting of those wearing a separate shoe and customized 3D-printed AFO. The Footscan® system recorded maximum pressure, maximum strength, and contact area of patients' hallux, toes 2-5, first to fifth metatarsal, midfoot, lateral heel, and midfoot heel at weeks 0 and 8. Patients used visual analogue scale scores at weeks 0 and 8 to assess overall comfort of foot orthosis, to determine the credibility and comfort of both orthopedic insole conditions. RESULTS At week 0, in the experimental group, peak pressure in the hallux and first metatarsal area was significantly higher than the control group (P<0.05), while mid-heel and lateral heel peak pressures were significantly lower than the control group (P<0.05). After 8 weeks, all groups reported more comfort compared with the same group in week 0 (P<0.05). The comfort scores reported by the experimental group were significantly lower than those of the control group (P<0.05). CONCLUSIONS This study supports the efficiency of customized 3D printing AFO for reducing damage associated with plantar lesions and improving comfort in patients with plantar fasciitis compared with prefabricated AFO. Customized AFO is useful in the treatment of plantar fasciitis compared with prefabricated AFOs.