Medical-grade footwear: the impact of fit and comfort

Development of a footwear sizing system for diabetic feet

The number of diabetic patients is increasing rapidly who have vulnerable feet and might be easily affected by different adversities. Since there is no available footwear sizing system for diabetic patients, manufacturers produce diabetic footwear of different sizes and fittings based on other available footwear sizing systems, which may result in inappropriate fitting. To get footwear with proper fittings, diabetic patients may go for customized or bespoke footwear based on their foot conditions, which is very costly. This study attempts to explore the foot complications of diabetic patients and categorize their feet to create a new sizing system using foot measurements from 102 male diabetic patients based on three dimensions of human feet, namely foot length, ball girth, and instep circumference. K-means data clustering is followed to categorize the data into three broad groups, namely small, medium, and large groups for footwear sizing. The developed footwear sizing system uses a sizing interval of 8 mm and a fitting interval of 6 mm. This study suggests a total of 11 sizes along with 24 different fittings for the footwear manufacturers for producing diabetic footwear. This newly developed footwear sizing system has a total of 79.41 % coverage where there are 10, 10, and 4 fittings in the small, medium, and large groups, respectively. The proposed footwear sizing system can help footwear manufacturers understand the proper size and fit of diabetic patients' feet so that they can make appropriate footwear for diabetic patients economically.

Efficacy of auxetic lattice structured shoe sole in advancing footwear comfort-From the perspective of plantar pressure and contact area

Introduction

Designing footwear for comfort is vital for preventing foot injuries and promoting foot health. This study explores the impact of auxetic structured shoe soles on plantar biomechanics and comfort, motivated by the integration of 3D printing in footwear production and the superior mechanical properties of auxetic designs. The shoe sole designs proposed in this study are based on a three-dimensional re-entrant auxetic lattice structure, orthogonally composed of re-entrant hexagonal honeycombs with internal angles less than 90 degrees. Materials fabricated using this lattice structure exhibit the characteristic of a negative Poisson's ratio, displaying lateral expansion under tension and densification under compression.

Methods

The study conducted a comparative experiment among three different lattice structured (auxetic 60°, auxetic 75° and non-auxetic 90°) thermoplastic polyurethane (TPU) shoe soles and conventional polyurethane (PU) shoe sole through pedobarographic measurements and comfort rating under walking and running conditions. The study obtained peak plantar pressures (PPPs) and contact area across seven plantar regions of each shoe sole and analyzed the correlation between these biomechanical parameters and subjective comfort.

Results

Compared to non-auxetic shoe soles, auxetic structured shoe soles reduced PPPs across various foot regions and increased contact area. The Auxetic 60°, which had the highest comfort ratings, significantly lowered peak pressures and increased contact area compared to PU shoe sole. Correlation analysis showed that peak pressures in specific foot regions (hallux, second metatarsal head, and hindfoot when walking; second metatarsal head, third to fifth metatarsal head, midfoot, and hindfoot when running) were related to comfort. Furthermore, the contact area in all foot regions was significantly associated with comfort, regardless of the motion states.

Conclusion

The pressure-relief performance and conformability of the auxetic lattice structure in the shoe sole contribute to enhancing footwear comfort. The insights provided guide designers in developing footwear focused on foot health and comfort using auxetic structures.

Effectiveness of footwear and foot orthoses in reducing medial metatarsophalangeal joint pressure in women with hallux valgus

BACKGROUND

Hallux valgus is a common condition where the subluxation of the first metatarsophalangeal joint and lateral deviation of the hallux at the interphalangeal joint creates difficulty with footwear fit. Footwear and foot orthoses are commonly prescribed nonsurgical treatments for hallux valgus.

RESEARCH QUESTION

Do extra-width footwear and foot orthoses influence peak pressure at the medial aspect of the metatarsophalangeal and interphalangeal joints in women with hallux valgus?

METHODS

Community-dwelling women with symptomatic hallux valgus underwent gait testing when wearing their own shoes and when wearing extra-width footwear fitted with three-quarter length, arch-contouring prefabricated foot orthoses. Peak pressure (kPa) on the medial aspect of the metatarsophalangeal and medial interphalangeal joints and on the plantar surface of the foot (hallux, lesser toes, metatarsophalangeal joint 1, metatarsophalangeal joints 2-5, midfoot and heel) were measured using the novel pedar®-X system with the pedar® pad and pedar® insole, respectively (Novel, GmbH, Munich, Germany). Paired samples t-tests were used to calculate the differences between the two conditions, and the magnitude of observed differences was calculated using Cohen's d.

RESULTS

We tested 28 participants (aged 44-80 years, mean 60.7, standard deviation 10.7). Compared to their own footwear, wearing the intervention footwear and orthoses was associated with a statistically significant decrease in pressure on the medial aspect of the metatarsophalangeal joint (58.3 ± 32.8 versus 42.6 ± 32.8, p=0.026, d=0.49), increased pressure under the midfoot (70.7 ± 25.7 versus 78.7 ± 23.6, p=0.029, d=0.33) and decreased pressure underneath the heel (137.3 ± 39.0 versus 121.3 ± 34.8, p=0.019, d=0.45).

SIGNIFICANCE

The intervention footwear and orthoses significantly decreased peak pressure on the medial aspect of the first metatarsophalangeal joint but had no significant effect on the interphalangeal joint. Further studies are required to determine whether these changes are associated with improvements in symptoms associated with hallux valgus.

Enhancing Footwear Safety for Fall Prevention in Older Adults: A Comprehensive Review of Design Features

BACKGROUND

Falls are a global concern affecting people of all ages; however, older adults are particularly vulnerable to age-related factors and foot-related issues. Footwear is critical for preventing falls, as it provides stability and protection against slips, trips, and falls (STFs). However, a significant gap exists in the systematic exploration of the safety aspects of footwear design for fall prevention in older adults.

METHODS

This comprehensive review applied a meticulous search strategy encompassing prominent databases, including Google Scholar, ScienceDirect, SCOPUS, MEDLINE, ResearchGate, and PubMed. This review synthesized and analyzed existing research to bridge knowledge gaps and provide insights into optimal footwear choices for older adults in terms of design features such as fit, fixation, heel height, collar height, slip resistance, and sole/insole hardness.

RESULTS

The results underscore the importance of specific design features for preventing falls among older adults. A proper fit, secure fixation, appropriate heel and collar heights, slip resistance, and sole/insole hardness significantly contributed to fall prevention. These findings offer valuable guidance for optimizing footwear designs to enhance comfort, stability, and safety in the daily lives of older individuals.

CONCLUSION

This comprehensive review fills a critical knowledge gap regarding the safety of footwear designs for fall prevention in older adults. The identified design features play a vital role in reducing the risk of falls and offer practical recommendations for the development of safer footwear. Ultimately, this study contributes to the existing knowledge base and supports efforts to prevent STFs in older adults through improved footwear design.

Predictive factors for foot pain in the adult population

BACKGROUND

Foot pain has been associated to factors like: fat, body mass index, age increased, female gender and the presence of pathologies. Although evidence is limited. The purpose is to determine the predictive factors for foot pain in the adult population.

METHODS

From January to December 2021, 457 patients were > 18 years, gave signed informed consent to take part to this cross sectional study. All completed demographic data and various questionnaires related to pain: Foot Function Index, EuroQoL-5D and Visual Analogue Scale (foot pain). Anthropometric measurements were obtained using McPoil platform and foot posture was assessed by the Foot Posture Index (FPI). To determine whether a volume change is a predictive factor for foot pain, a parameter was established: the volumetric index for footwear (VIF). Factors linked to the presence of pain, including the considered VIF variables, were analyzed through multivariable logistic regression.

RESULTS

Among the study population, 40.7% were male and 59.3% female. The mean age of 39.06 years and a body mass index of 25.58 Kg/cm2. The logistic regression model had a classification capability of 72.4%, a sensitivity of 72.3% and a specificity of 73%, in which, the predictors considered were the variables found to have a significant association with FFI-pain > 45 points,, showed that younger women, with a higher BMI, higher values of right FPI (pronation), poorer overall perceived health and with problems in walking were more likely to experience foot pain.

CONCLUSION

Predictive factors for foot pain in the adult population include gender, age, Body Mass Index, FPI on the right foot, perceived health and mobility. Clinical implication, the presented measure aids physicians in assessing their patients´ foot pain likelihood.

Increased footwear comfort is associated with improved running economy - a systematic review and meta-analysis

Footwear with or without custom foot orthotics have the potential to improve comfort, but the link with running performance needs further investigation. We systematically reviewed the association of footwear comfort on running economy in recreational runners. Nine electronic databases were searched from inception to March 2020. Eligible studies investigated both direct outcome measures of running performance (e.g. running speed) and/or physiological measures (e.g. running economy (RE)) alongside comfort for each footwear condition tested. Methodological quality was assessed using the "Effective Public Health Practice Project" (EPHPP). RE during submaximal running was the most common physiological outcome reported in 4 of the 6 eligible studies. The absolute difference in RE between the most and least comfortable footwear condition was computed, and meta-analysis was conducted using a random effect model. The most comfortable footwear is associated with a reduction in oxygen consumption (MD: -2.06 mL.kg^-1.min^-1, 95%CI: -3.71, -0.42, P = 0.01) while running at a set submaximal speed. There was no significant heterogeneity (I² = 0%, P = 0.82). EPHPP quality assessment demonstrated weak quality of the studies, due to reporting bias and failing to disclose the psychometric properties of the outcome measures. It can be concluded with moderate certainty that improved RE in recreational athletes is associated with wearing more comfortable footwear compared to less comfortable footwear.HighlightsThis systematic review reports on the association of footwear comfort with running economy in recreational runners.Running economy during constant submaximal running is likely improved in recreational runners wearing more comfortable compared to less comfortable footwear.This finding is based on a meta-analysis, including four studies, showing a small but statistically significant decreased oxygen consumption at steady state speeds while wearing the most comfortable footwear.

Clinical Efficacy of a 3D Foot Scanner app for the Fitting of Therapeutic Footwear in Persons with Diabetes in Remission: A Randomized and Controlled Clinical Trial

To evaluate the ability of high-risk patients with diabetes in remission to select proper therapeutic footwear (TF) and validate a novel 3D foot scanner app for selecting the proper fitting TF. We conducted a randomized and controlled clinical trial enrolling 30 patients with a previously healed diabetic foot ulcer carried out in a specialized diabetic foot unit between November 2021 and June 2022. All patients were recommended to TF with extra depth volume and rocker sole. The control group could acquire the TF size and model according to aesthetic preferences, while the experimental group had to acquire a specific size and model according to the result of a novel mobile app 3D feet scan. TF was recommended to change when the ill-fitting reasons were found, excessive length or tightness or compromise with toes. The primary outcome measure was the requirement of TF change after prescription because of ill-fitting. A total of seven patients required TF change, one of them (6.7%) in the experimental group and six patients (40%) in the control group (p = .031, 95% CI [0.011-1.04]). Reasons for ill-fitting were as follows: four patients due to excessive length and three patients due to toe compromise. The relative risk reduction for the need to change the TF via the foot scan compared to the control group was 83%, and the number needed to treat was 20. High-risk patients with diabetes tend to select TF with inadequate fitting (length or capacity), and they should be guided hand to hand to acquire proper TF.

Relationships between the Perception of Footwear Comfort and the Fear of Falls in People at the Early Period of Old Age

Objective: The present study aimed to analyze the relationships between the perceptions of footwear comfort with fear of falls in younger-old women and men. Participants: the population sample involved 100 free-living community dwellers aged 65−74. Design: the Falls Efficacy Scale-International and a visual analogue scale to assess perception of footwear comfort were used as research tools. Results: there were statistically significant differences in the FES-I results in people who suffered a fall in the last year compared to those who did not experience a fall (p < 0.001), as well as in the subjective assessment of mediolateral control in people who have suffered and have not suffered a fall in the last year (p = 0.033). In women, statistically significant relationships were found in the subjective assessment of shoe comfort in terms of arch height (p = 0.025) and material properties of the footwear (p = 0.036) with the results of FES-I. Conclusions: People who have fallen show a higher level of fear of falling. The assessment of footwear comfort in terms of mediolateral control was lower in the younger-old who had experienced a fall in the last year. In women, a worse assessment of arch height and material properties of the footwear is accompanied by greater fear of falling.

Perception of footwear comfort and its relationship with the foot structure among youngest-old women and men

Background

Adequate footwear comfort and functionality are important regardless of age, but they become particularly important in the youngest-old women and men, mainly due to the fact that this age range is the initial period of old age with changes in shoe preferences. The aim of this study was to assess the perception of footwear comfort and its relationship with the feet structure in youngest-old women and men.

Methods

The cross-sectional study covered community dwellers living on their own aged 65–74 years (50 women; 50 men). The feet characteristics were measured using the CQ-ST podoscope (Electronic System, Ltd, EU), and the perception of footwear comfort was assessed with a visual analogue scale. The assessment took into account gender-specific footwear of a certain brand (Befado Dr orto).

Results

Statistically significant intergender differences were observed in the perception of footwear comfort with respect to the shoe heel width (p = 0.022), the arch height (p = 0.013), the overall comfort (p = 0.049) and the material properties of the footwear (p = 0.017). In women, there were statistically significant positive relationships among the heel angle (γ) and the perception of footwear comfort in terms of heel cushioning (p = 0.021), forefoot cushioning (p = 0.015), arch height (p = 0.029). In men, there was a statistically significant negative relationship of the left foot Clarke’s angle with the heel height (p = 0.043), and a positive relationship between the right foot width and the arch height (p = 0.044).

Conclusions

Youngest-old women, compared to men of the same age range, have a higher perception of shoe comfort in terms of the shoe heel width, the arch height, the overall comfort of the footwear and the material properties of the footwear. The appropriate profile and construction of the shoe allows for an increase in the contact surface of the foot with the shoe, hence the improvement in the perception of footwear comfort in people with lowered arch or widened forefoot.

The immediate effects of hallux valgus orthoses: A comparison of orthosis designs

BACKGROUND

Hallux valgus orthoses are available in a wide range of designs and materials, but the effects of their design on functional performance have not been fully investigated.

RESEARCH QUESTION

This present study aims to comprehensively analyze the immediate effects of soft and semi-rigid hallux valgus orthoses on balance, plantar pressure, hallux valgus angle, and subjective sensations.

METHODS

Sixteen female subjects have participated in the study, including 10 subjects with healthy feet and 6 with hallux valgus. Three conditions are tested, including in the barefoot and using two types of commercially available hallux valgus orthoses. The subjects participate in static and dynamic (walking) tests with the use of the Novel Pedar® system. The peak pressure values in the hallux, lateral toes, first metatarsophalangeal joint, 2-4th metatarsal heads, 5th metatarsal head, medial midfoot, lateral midfoot and rearfoot in the various foot conditions are examined and compared. The hallux valgus angle of each subject is measured based on their footprint. Their subjective feelings towards the orthoses are also evaluated. A repeated-measures analysis of variance, and independent-sample t-test are performed.

RESULTS

The correction of the hallux valgus angle is statistically significant when the subjects with hallux valgus use the orthoses. In comparing the two types of orthoses, the use of the orthosis made of soft materials results in correction in the hallux valgus angle and higher wear comfort, and lower plantar pressure in hallux area.

SIGNIFICANCE

The results provide insights into the design of hallux valgus orthoses, thus offering practical reference for the selection of hallux valgus orthosis with compromise between functional performance and wear comfort.

Toe gaps and their assessment in footwear for people with diabetes: a narrative review

BACKGROUND

Adequate footwear fit is critical in preventing diabetes-related foot ulcers. One important element is the toe gap, the difference between foot length and internal footwear length available to the foot. We summarised the literature on toe gaps in studies assessing footwear worn by people with diabetes, the methods used to measure both foot length and internal footwear length and identify ambiguities which may impact on toe gap assessment in clinical practice, and suggest pragmatic solutions.

METHODS

The Google Scholar database was searched to April 2020 for peer-reviewed studies using keywords related to incorrectly fitting or ill-fitting and diabetes, foot and ulcer which returned 979 results. Included studies within this narrative review encompassed toe gap measurement to assess footwear worn by people with diabetes.

RESULTS

A total of eight studies were included after full paper review. Toe gap ranges as used in assessments of footwear worn by people with diabetes vary, with a minimum of 1.0-1.6 cm and a maximum of 1.5-2.0 cm, as do methods of measuring internal footwear length. Only three published studies suggested possible measuring devices.

CONCLUSIONS

Toe gap ranged as used when assessing footwear fit in people with diabetes vary and a gold standard device for internal footwear length measurement has yet to emerge. International guidelines provide welcome standardisation, but further research is needed to evaluate both the effect of toe gap ranges upon pressure, plantar stress response and ulceration and available measuring devices to facilitate development of toe gap measurement protocols that may further enhance consistency in practical assessments.

Comparative study of the strength characteristics of a novel wood-plastic composite and commonly used synthetic casting materials

BACKGROUND

Woodcast® is a wood-plastic composite casting material that becomes pliable and self-adhesive when heated to 65 °C and returns to being weightbearing as it cools down. The present study aims to test whether this novel non-toxic casting material is strong enough for clinical use by comparing its strength against materials that are already used in weightbearing casting applications such as total contact casts.

METHODS

The strength of Woodcast® samples was compared against the strength of two commonly used synthetic casting materials (Delta-Cast®, OrthoTape). The effect of environmental factors such as cooling, prolonged heating and exposure to water was also assessed.

FINDINGS

The results of this study indicated that Woodcast® is stronger than the synthetic casting materials in compression but weaker in tension. The flexural strength of Woodcast® was 14.24 MPa (±1.25 MPa) while the respective strength of Delta-Cast® and OrthoTape was 18.96 MPa (±7.46 MPa) and 12.93 MPa (±1.93 MPa). Independent samples t-test indicated that the difference between Woodcast® and the other two materials was not statistically significant (P > .05). Woodcast® recovered 90% and 78% of its tensile or flexural strength respectively after 15 min of cooling at ambient temperature and its strength was not reduced by prolonged heating. On average, exposure to water reduced the flexural strength of Delta-Cast® by 6% and of OrthoTape by 44%. The strength of Woodcast® was not affected by exposure to water.

INTERPRETATION

The comparison between Woodcast® and commonly used synthetic casting materials indicated that Woodcast® is indeed strong enough to be safely used in weightbearing casting applications.

Footprint Curvature in Spanish Women: Implications for Footwear Fit

The incorrect adjustment of footwear produces alterations in the foot that affect quality of life. The usual measurements for shoe design are lengths, widths and girths, but these measures are insufficient. The foot presents an angle between the forefoot and the rearfoot in the transverse plane, which is associated with foot pronation, hallux valgus and metatarsus adductus. Here, we aimed at identifying the groups formed by the angulations between the forefoot and rearfoot using a sample of footprints from 102 Spanish women. The angle between the forefoot and rearfoot was measured according to the method described by Bunch. A cluster analysis was performed using the K-means algorithm. Footprints were grouped into three types: curved, semi-curved and straight, according to the degrees of angulation between the forefoot and rearfoot. There is great variability in the morphology of the foot. Based on our findings, to achieve a better footwear fit, we propose the manufacture of three types of lasts with different curvatures.

Monitoring of external predisposing factors for Diabetic Foot: A literature review and physicians' perspectives

Background: Diabetic foot is one of the most important complications of diabetes caused by the existence of some destructive factors in different anatomical locations of feet. Management and monitoring of these factors are very important to decrease or avoid ulcerating lesions of the foot. The purpose of this study is to identify and introduce the predisposing factors and anatomical locations associated with these destructive factors. Methods: First, we conducted a comprehensive review of different databases to identify the factors and associated anatomical locations from the previous studies. Then, we designed a questionnaire and invited physicians and specialists to express their perspectives on these factors and locations. The data were analyzed using SPSS version 23. Frequency, percentage, mean and standard deviation of these variables were calculated. Results: Based on the literature review, four factors, including pressure, moisture and sweat, temperature, and acceleration were identified as factors destructive to the tissues of the diabetic foot and worsen ulcers. The view of specialists approved the results of the literature review. Besides, there was an insignificant difference between the results of the literature review and the specialists' view in terms of anatomical locations that need to be continuously monitored. Conclusion: Monitoring the pressure in heel, first metatarsal, and first metatarsal head; moisture and sweat under the fingers, hallux and heels as well as the temperature at the first metatarsal, first metatarsal head, and the third metatarsal head are important in preventing ulceration, destructing the foot tissue, and accelerating the treatment process.

Everyday footwear: An overview of what we know and what we should know on ill-fitting footwear and associated pain and pathology

Footwear has been used to protect feet for millennia with socially exclusive population adopting stylish and fashionable shoes with expensive materials. In terms of historic timeline, only more recently footwear has been worn by all classes in the western world as an integral part of their apparel. Traditionally, footwear has been constructed from natural materials, mainly leather, but has recently benefitted from the flexibility that technology has provided with a plethora materials and new design innovations. Although it has expanded the availability for a variety of consumers, the choice and fit continue to be problematic with many individuals wearing shoes that are ill-fitting. Provision of specific footwear advice for problem feet is poorly evidenced and is heavily practitioner dependant limiting its efficacy. There is limited understanding as to the changes that can occur from regularly wearing footwear that is unsuitable in shape, style and construction which is referred to as ill-fitting. Current research on the effect that everyday footwear has on foot function and pain focuses mainly on women's shoes, particularly high heels. Defining what is a good fitting shoe, that does not damage the foot or mechanics of walking, may need to be individualised, but best fit is based on loose historical parameters rather than research evidence. The aim of this overview is to highlight aspects of current research, establishing what is known about the effect's shoes have on the feet as well as exploring the mythology around footwear fit and advice that is often historical in nature.

An integrative review of therapeutic footwear for neuropathic foot due to diabetes mellitus

BACKGROUND

Therapeutic footwear is built on a model of patient's foot, for people with diabetes suffering with neuropathy. Can the footwear helps to improve plantar pressure in neuropathic foot? This study focussed on available data on therapeutic footwear as an intervention for improving and offloading plantar pressure in neuropathic diabetic foot.

METHODS

Relevant scientific literature in PubMed, Medline and Google Scholar published between 2000 and 2017 were searched. The keywords searched were therapeutic footwear, plantar pressure, neuropathic foot, rocker sole, ulcer healing and offloading of plantar pressure. Articles on randomized controlled trials, observational, cohort, feasibility and factorial studies were reviewed.

RESULTS

One hundred and twenty five (125) articles were identified. The article comprised of 6 randomized controlled trials, 2 observational, 1 cohort, 1 feasibility and 1 factorial study met the inclusion criteria and were critiqued with a total enrolment of 1380 study subjects.

CONCLUSIONS

The review of the collated literature demonstrated that, therapeutic footwear can improve the healing of neuropathic diabetic foot ulcer by redistributing plantar pressure. However, the efficacy of therapeutic footwear requires the inclusion of technical features that should not be compromised from the design to the production of the footwear.