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

Abstract

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.

Keywords

diabetic foot ulcer therapeutic footwear ill-fitting shoes prevention

Introduction

Diabetic foot ulcers (DFU) have become a serious complication secondary to diabetic foot syndrome; it has been stated in previous research that 19–34% of patients with diabetes will develop a DFU during their life.¹ Even after ulcer resolution, patients will suffer from high recurrence rates, being an unsolved issue and rising the recurrence rates to 65% after 5 years.¹ Providing structured education about foot-specific self-care has been demonstrated to effectively prevent a first-ever or recurrent and should consist of information on wearing adequately protective footwear.² Among the recommended therapies for preventing diabetic foot disease, orthopedic devices such as therapeutic footwear (TF)^3–5 have been demonstrated to prevent foot ulcers.

TF has become one of the most prescribed non-medical therapies to prevent diabetic foot and its complications (2). TF has been widely studied in the literature, and the design of the outsole^6–9 and the mechanical characteristics are topics with a high evidence level.¹⁰ The footwear is engineered to offer proper arch support and reduce the magnitude of plantar pressure on the metatarsal heads and bony prominences, which may build excessive hyperkeratotic tissues that eventually ulcerate.^11,12 International Working Group of Diabetic Foot (IWGDF)² guidelines recommend that people with loss of protective sensation (LOPS) or peripheral artery disease (PAD) must take extra care when selecting, or being fitted with, footwear; this is most important when they also have foot deformities (IWGDF risk-2) or have a history of a previous ulcer/amputation (IWGDF risk-3). Recommendations for footwear fitting are focused on TF length, the width of the metatarsal heads, and enough height to allow room for all the toes and possible deformities.² Despite the many advantages and advancements in the design of diabetic footwear, foot ulcerations still occur, with a high risk of reulcerations.¹³ Poorly fitting shoes in which soft tissues of the foot are under pressure for an extended period¹⁴ can lead to ulcer occurrence, some of which will lead to amputation.¹⁵ Between the causes of ill-fitting shoes, the literature mainly describes narrow shoes or thigh fitting shoes,^16–18 blisters from wearing new shoes,³ and sores from new shoes provided by a non-expert orthotist.¹⁹ Inappropriate shoe size becomes another reason for non-fitting TF; previous authors^20,21 have examined the footwear size of persons with diabetes and found that many of them are wearing inappropriate footwear during daily activities. Loss of protective sensation secondary to diabetic peripheral neuropathy (DPN) skews sensory perceptions and can alter the proper selection of the TF.

In clinical practice, TF fitting is evaluated with the patient in the standing position, preferably later in the day (when they may have foot swelling), comparing the foot shape with footwear dimensions. Due to peripheral neuropathy, previous DFU, and minor amputation, the structure of the foot in high-risk patients (IWGDF risk-3) differs from those without foot complications (IWGDF risk 1-2). International guidelines recommend developing and implementing advanced interventions for foot self-management in ulcer prevention; thus, an accurate and reliable method to obtain the foot contours is paramount for orthopedic footwear to provide optimal fit and foot protection.

To our knowledge, no research has compared the ability of diabetes high-risk patients in remission in selecting the proper footwear size and characteristics to avoid foot complications. This study's aims were: 1) to evaluate the ability of high-risk patients with diabetes in remission to select the proper TF; and 2) to validate a novel 3D foot scanner app for selecting the proper fitting TF.

Material and Methods

Study Design

We performed a randomized and controlled parallel (1:1) clinical trial of patients with diabetes between November 2021 and June 2022. This study was approved by a local ethics in November 2021. Each patient provided written informed consent before inclusion according to the guidelines of the Declaration of Helsinki.²²

Participants

We enrolled patients from an outpatient specialized diabetic foot unit. Inclusion criteria were confirmed type 1 or type 2 diabetes, age > 18 years, LOPS as a result of DPN, and previous foot ulcer in the foot (IWGDF-risk 3 patients in remission). Exclusion criteria were ulcer during the examination, transmetatarsal or major amputation (below or above the knee), history of rheumatoid disease, other neuropathy causes, and need for custom-made footwear due to severe foot deformity and need for walking aids. Patients who rejected the TF for esthetic purposes were also excluded, based on a study reporting that patient dissatisfaction with the prescribed footwear results in low adherence rates.²³

3D Foot Scan and Therapeutic Footwear

The patients were randomly assigned to the control or experimental group. A study flow diagram is shown in Figure 1.

Both groups (Podartis s.r.l Unipersonale—Crocceta del Montello (TV), Italy) were prescribed with manufactured TF with the same general characteristics regardless of the allocation: high toe box; extra width to accommodate toe deformities such as claw or hammer toes, and a wide heel; and laces or buckles for fasteners. Furthermore, the shoes were free of seams, folds, and hollows.⁴ All the patients wore a total contact insole to decrease peak pressures in the plantar aspect of the foot. The sole density was the same for both groups, a rigid (composite fiber, density 330 kg/m² Shore A) sole.⁶ All shoes had a rocker sole (ie, an anteroposterior rocker) for plantar pressure reduction of the metatarsophalangeal joints. The pivot point needed to be proximal to these joints. The rocker angle was defined as the 20° angle between the floor and sole under the metatarsal heads.⁶

Control group participants acquired their TF size and model according to aesthetic preferences (standard TF prescription); while the experimental group participants had to acquire a specific size and model according to the result of a novel mobile app 3D feet scan (smart-fitting by Podiapp - Podartis s.r.l Unipersonale-Crocceta del Montello (TV), Italy), the scanner delivers an accuracy of up to 0.05 mm. Also, the foot station used in this study enables efficient scanning of the dorsal, medial, and lateral surface of the foot. The foot scan was performed for every patient's foot in the standing position with half weight-bearing as recommended by previous research²⁴ due to the optimal combination of foot deformation secondary to different body loads. For the foot scan, patients were requested to stand upright with equal loading on each foot over the calibrated foot station (it consists of 43-calibrated points slide with a foot shape in the middle of the foot station) (Fig 2A). Then, the clinician tried to take as many points as possible with the phone horizontally to make that viable (Fig 2B). The algorithm did not consider photos with points below a fixed threshold, but the more points are taken into the picture, the more accurate the model will be. For a perfect 3D foot reconstruction, the clinician must take between 18 and 24 pictures of the foot at 360° with a 45° of phone angulation. During the acquisition the patient was asked to remain in a stable position. For a better foot reconstruction, we tried to not include the other foot in the acquisition for a better capture of the photo. After the 3D reconstruction of the foot (Fig 2C), the software recommended the ideal TF based on foot anthropometric characteristics (foot length, foot width, metatarsal circumference, and forefoot width).

Figure 2 legend. A. Half weigh bearing position of the patient over the calibrated foot station; B. Acquisition of foot pictures of the foot in 360° with a 45° of phone angulation; C. 3D reconstruction of the foot.

For both study groups, patients were asked to acquire their TF and instructed to return to the diabetic foot outpatient clinic to properly validate the fitting of their shoes.

Validation of proper TF fitting was performed by a specialized podiatrist with more than 5 years of experience in foot biomechanics via exploration of visual foot points in the print of the therapeutic footwear in weight-bearing and walking positions. TF was recommended to change when the following ill-fitting reasons were found, excessive length or tightness (checked by direct palpation of the largest toe with a minimum requirement of 1.5 centimeters between the toe and the distal cover of the TF) or compromise with toes (checked by direct palpation of the dorsum of the interphalangeal joint of the minor toes and the hallux). We evaluated these criteria in the forefoot, due to previous literature have focused in evaluating ill-fitting ulcers in the toes.^16–18

Outcome Measures

The primary outcome measure was the requirement of therapeutic footwear change after prescription because of the ill-fitting shoe. The secondary outcome measure was the presence of a recurrent event during a 6-month follow-up period, which was defined according to the IWGDF guidelines.²⁵ The investigator who assessed TF fitting and presence of ulcer occurrence was blinded to the randomization and allocations of participants.

At baseline, clinical characteristics were assessed after the patient signed informed consent on day 0. Body mass index (BMI) was calculated as weight (kg) divided by height (m²). Clinicopathologic data were collected, including diabetes type, mean duration of diabetes, and HbA1c (%) values in the previous 3 months.

Loss of protective sensation secondary to DPN was confirmed by the inability to sense the pressure of a 10-g Semmes-Weinstein monofilament at three plantar foot sites and/or a vibration perception threshold >25 V as assessed via the biothesiometer (Me.Te.Da. s.r.l., Via Silvio Pellico, 4, 63074 San Benedetto del Tronto AP, Italy) (26). Additionally, foot pulses, ankle-brachial index (ABI), and toe brachial index (TBI) were calculated for every patient (27).

Forefoot deformities were considered when the foot presents any of the following conditions: toe contractures (such as hammertoe), bony prominences, and hyperkeratosis.^26,27

TF adherence was evaluated monthly using the Monitor Orthopedic shoes (MOS) questionnaire²⁸ and stratified into patients who achieved less than 80% of daily TF adherence and more than 80% of daily TF adherence. The MOS questionnaire is a practical and reproducible questionnaire that can be used for a wide range of patients with foot problems.²⁸ However, most of the questions on the original version were not relevant for this research. We therefore used a shortened version of the MOS regarding the frequency and daily duration of use of TF.

The study investigator randomly assigned subjects using a computer-generated randomization table in a balanced design (1:1) to (1) 3D scanner guided TF prescription or (2) standard TF prescription. The randomization was performed by an investigator who was unaware of the identity of the participants (J.L.L.M.). The caregiver investigators received the allocated participant number by email.

For the analyses of the secondary outcomes, patients were asked to come for a clinical visit monthly, according to the international guidelines,²⁹ until the 6-month follow-up period.

Statistical Analyses

Univariate analysis for risk factors associated with shoe-fitting conditions was performed using the Chi-square test for categorical variables and the Student t-test for quantitative variables using SPSS version 20.0 (SPSS, Chicago, IL, USA). The strength of difference in the effect size was calculated by Phi coefficient for the chi-square test and r coefficient for the non-parametric test considering the values >.01 as a small effect, >.30 as a medium effect, and >.50 as a large effect. Cohen's d was calculated as the effect size for the parametric test using the effect size calculator (http://www.uccs.edu/∼lbecker/) and considering the values >.2, >.5, and >.8 as small, moderate, anlarge effects, respectively.³⁰

Relative risk reduction $(RRR = \frac{E x p e r i m e n t a l g r o u p r i s k - C o n t r o l g r o u p r i s k}{C o n t r o l g r o u p r i s k})$ and the number needed to treat $(NNT = \frac{1}{E x p e r i m e n t a l g r o u p r i s k - C o n t r o l g r o u p r i s k})$ were used to estimate the size of the effect.

The sample size calculation was based on a previous study of six persons with diabetes who assessed the foot shape with a 3D laser measurement.³¹ As a relevant risk reduction, we assumed a difference in the unfitting rate of 15% in the patients prescribed with a 3D foot scanner based on what we considered a relevant risk reduction compared with the group of patients prescribed with a standard prescription. With a 0.05 setting (one-sided), power of 0.80 in an × 2 analysis, and an anticipated loss to follow-up of 10%, we intended to include 30 patients (15 in each group).

Results

A total of 30 patients were included in the study, and they were randomly assigned to two different groups: the control group (n = 15) and the experimental group (n = 15).

Data on demographics, diabetes, and foot complications were collected at baseline (Table 1).

Table 1.

legend: sd, standard deviation. Control group: standard TF prescription; experimental group: 3D scanner guided TF prescription group.

Baseline Characteristics	All patients(N = 30)	Control Group(n = 15)	Experimental Group(n = 15)	P-value[95% CI]	Effect size
Male, n (%)	24 (80%)	12 (80%)	12 (80%)	0.987	-
Female n, (%)	6 (20%)	3 (20%)	3 (20%)	0.987	-
Type 2 Diabetes, n (%)	26 (86.7%)	14 (93.3%)	12 (80%)	0.283	0.196
Type 1 Diabetes, n (%)	4 (13.3%)	1 (6.7%)	3 (20%)	0.283	0.196
Permeable Pedal Pulses, n (%)	11 (36.7%)	4 (26.7%)	7 (46.7%)	0.256	0.208
Previous minor amputation, n (%)	21 (70%)	12 (80%)	9 (60%)	0.232	0.218
Ankle Brachial Pressure Index, mean ± SD	1.13 ± 0.26	1.09 ± 0.27	1.17 ± 0.25	0.463	0.307
Toe Brachial Pressure Index, mean ± SD	0.74 ± 0.17	0.78 ± 0.15	0.70 ± 0.18	0.214	0.282
Mean age ± SD (years)	65.1 ± 11.75	63.8 ± 10.25	66.4 ± 13.31	0.544	0.218
Glycated hemoglobin mmol/mol (%), mean ± SD	8.4 ± 1.58	8.2 ± 1.28	8.6 ± 11.58	0.492	0.048
Diabetes mellitus (years), mean ± SD	15.5 ± 10.35	12.33 ± 8.05	18.86 ± 11.58	0.084	0.342
Body Mass Index (kg/cm²)	24.11 ± 4.57	24.14 ± 5.45	24.09 ± 3.67	0.987	0.010
Hammer Toe, n (%)	22 (73.3%)	11 (73.3%)	11 (73.3%)	0.876	0
Bony prominence, n (%)	24 (80%)	13 (86.7%)	11 (73.3%)	0.361	0.167
Hyperkeratosis, n (%)	27 (90%)	14 (93.3%)	13 (86.7%)	0.543	0.111

Data on the location of previous foot ulcers were collected in Table 2.

Table 2.

Previous ulcer location for both study groups.

Previous ulcer location	Control Group (n = 15)	Experimental Group (n = 15)
Hallux	2 (13.3%)	3 (20%)
Minor Toes	1 (6.7%)	5 (33.3%)
Metatarsal Head	10 (66.7%)	6 (40%)
Midfoot	1 (6.7%)	-
Heel	1 (6.7%)	1 (6.7%)

Seven patients in the sample required TF change (23.3%), one of them (14.3%) in the experimental group and six patients (85.7%) in the control group (p = .031, 95% CI [0.011-1.04]) (Table 3).

Table 3.

Univariate analyses.

Baseline Characteristics	Ill-fitting TF requires change(n = 7)	Non-ill-fitting TF require change(n = 23)	P-value[95% CI]	Effect size
Male, n (%)	7 (100%)	17 (73.9%)	0.131	0.27^a
Female n, (%)	-	6 (26.1%)	0.131	0.27^a
Type 2 Diabetes, n (%)	7 (100%)	19 (82.6%)	0.236	0.21^a
Type 1 Diabetes, n (%)	-	4 (17.4%)	0.236	0.21^a
Permeable Pedal Pulses, n (%)	2 (28.6%)	9 (39.1%)	0.61	0.09^a
Previous minor amputation, n (%)	7 (100%)	14 (60.9%)	0.048*	0.36^a
Ankle Brachial Pressure Index, mean ± SD	1.03 ± 0.19	1.16 ± 0.74	0.252	0.24^b
Toe Brachial Pressure Index, mean ± SD	0.77 ± 0.15	0.73 ± 0.18	0.633	0.24^b
Mean age ± SD (years)	62.57 ± 9.74	65.86 ± 12.38	0.525	0.29^b
Glycated hemoglobin mmol/mol (%), mean ± SD	8.32 ± 0.98	8.42 ± 1.74	0.89	0.07^b
Diabetes mellitus (years), mean ± SD	13.28 ± 11.19	16.3 ± 10.24	0.539	0.28^b
Body Mass Index (kg/cm²)	24.25 ± 5.04	24.07 ± 4.53	0.928	0.03^b
Hammer Toe, n (%)	5 (71.4%)	17 (73.9%)	0.896	0.02^a
Bony prominence, n (%)	7 (100%)	17 (73.9%)	0.131	0.27^a
Hyperkeratosis, n (%)	7 (100%)	20 (87%)	0.314	0.18^a
Control Group, n (%)	6 (85.7%)	9 (39.1%)	0.031*	0.41^a
Experimental Group, n (%)	1 (14.3%)	14 (60.9%)	0.031*	0.41^a

Note. DM, diabetes mellitus; SD, standard deviation; Kg, kilograms; cm², squared centimeters. TF, Therapeutic Footwear.

For categorical variables: chi-square test, as the Phi coefficient: 0.01 represents a small effect; 0.30 represents a medium effect, and 0.50 represents a large effect.

For normally distributed variables: Student’s t-test was used for independent samples; effect size was given by Cohen’s d: >0.2 for a small effect, >0.5 for a moderate effect, and >0.8 for a large effect; d is positive if the mean difference is in the predicted direction.

P<0.05 indicates statistical significance.

Reasons for ill-fitting were as follow: four patients due to excessive length and three patients due to toe compromise of the toe box.

The relative risk reduction (RRR) for the need to change the TF via the foot scan compared to the standard prescription was 83%, and the number needed to treat (NNT) was 20.

Secondary Outcome Measure

After the 6-month follow-up period, five patients (16.6%) suffered a recurrent event after TF validation, two of them (13.3%) in the experimental group and three (20%) in the control group, without statistical difference between groups (p = .624, 95% CI [0.087-4.341]. All the recurrent events were related to plantar foot ulcers beneath a metatarsal. All three recurrent patients were patients who required TF changed after standard prescription. Additionally, when analyzing TF adherence, all the patients included in the research exhibited more than 80% of daily adherence to using the prescribed TF.

Discussion

Our results show that patients” footwear choices based on characteristics and size should not be the choice for footwear prescription. Compared with a standard TF prescription, a 3D guided foot scan prescription reduces the risk of ill-fitting TF election in patients with previous plantar ulcers. Based on the results of the RRR, patients prescribed via the use of specialized technologies had an 83% lower risk of developing an ill-fitting footwear-related injury.

During the last few years, research has focused on their efforts to develop manufactured TF with preventive features that could protect the foot, decrease plantar pressure forces and reduce the recurrence and amputation rates.^32,33 These basic design specifications of TF are: sufficient interior space in length and width, with a minimum of 1 cm space in length between the longest toe and inner of the shoe, the box must be sufficiently high to accommodate foot deformities, no seams in the inner, use of laces and Velcro, and enough width to prevent scars from the presence of edema and sagittal deformities.³⁴

Despite progress in TF prescription and technical specifications, we demonstrate how 40% of patients with diabetes select unappropriated TF, even when using basic specifications, such as foot length and width, thus increasing re-ulceration risk. TF choices are often driven by patients” beliefs³⁵ and aesthetic characteristics^23,36; these modifiable factors must be taken into account, and clinicians should prescribe TF via objective tools and new technologies to prevent further foot complications.

In the current research, TF length and high pressure in the toes secondary to toes deformities with the toe box were the reasons for ill-fitting shoes. Previous research has demonstrated that medical-grade footwear reduces plantar pressures in the toes³⁷; despite this, they analyzed healthy subjects without DPN, which may further alter the perception when considering choosing a TF. Following the same trend, longer or shorter TF can lead to foot ulceration; it is thought that to obtain a good fit from a TF that a distance of 1 cm is required at the end of the toe to allow for elongation during the gait cycle and prevent complications.³⁸ This has particular implications for lesser toe deformities associated with wearing TF shorter or longer than the foot³⁹; in persons with diabetic foot, toe ulcers become one of the most common locations of ulcer occurrence in the foot.⁴⁰ Clinicians must focus on their efforts to prescribe the proper TF size; the current research demonstrated that compared to standard prescription and patients” own choice, an integrated 3D foot scan app is a more effective way to prescribe and recommend TF.

International Guidelines²⁹ recommend that you assess TF fitting under general conditions; despite this, they do not recommend assessing the fitting by clinicians and neither analyze the possibility of ill-fitting shoes with precise new technologies. This study opens a research field, not only for non-specialized clinicians but also for patients” self-management for the ease of use; the app is available for all mobile devices; in the future, researchers could investigate the relationship between foot-self management and foot complications with the use of this kind of technologies.

A thorough search of the literature reveals that this is the first study to clinically investigate the effectiveness of guided prescription of TF via 3D foot scanners to clinically decrease foot complications secondary to ill-fitting shoes. Efforts in diabetic foot prevention tend to look for the cost-benefit of implementing programs to prevent diabetes-related foot ulcers in high-risk populations compared with the cost of treating diabetes-related foot ulcers⁴¹; further research should confirm if 3D scanners decrease not only foot complications but even related costs.

However, our results should be interpreted with caution; patient blinding was not performed due to the impossibility of masking the intervention (use of a 3D foot scan app with a mobile phone device). Additionally, although the primary outcome measure (defined as the requirement of TF change after prescription because of an ill-fitting shoe) was assessed by an experienced clinician, further studies must confirm if the TF change after TF unfitting is necessary with the use of validated systems like in-shoe pressure or sear forces assessment.³⁷ Second, three patients developed a recurrent event during the follow-up in the plantar forefoot area, and all of them were patients with standard TF prescription; despite this, the three patients were not related to ill-fitting TF, and the recurrence was related to higher plantar pressures and the presence of hyperkeratosis.

Unfortunately, the plausibility of the results may be limited by the relatively low number of participants, further research should validate the primary outcome measure in a separate cohort; additionally, patients were not matched for important confounding variables known to cause DFU, thus the primary outcome measure could be biased.

Conclusion

High-risk patients with diabetes tend to select manufactured TF with inadequate fitting in length or capacity, and they should be guided hand to hand to acquire proper TF. A 3D foot scanner app is a reliable device to measure foot shape and can help high-risk patients with diabetes in remission select an optimal fitting.

Footnotes

Trial Registration

The present study is registered on ClinicalTrial.gov (Registration no.: NCT05353114).

Acknowledgments

The authors gratefully acknowledge the support of the staff and patients of the Diabetic Foot Unit of the Complutense University of Madrid.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

ORCID iDs

Mateo López-Moral

Raúl J. Molines-Barroso

Yolanda García-Álvarez

Francisco J. Álvaro-Afonso

Marta García-Madrid

José Luis Lázaro-Martínez

References

Armstrong

Boulton

AJM

Bus

. Diabetic foot ulcers and their recurrence. N Engl J Med. 2017;376(24):2367-2375.

Bus

Lavery

Monteiro-Soares

, et al. Guidelines on the prevention of foot ulcers in persons with diabetes (IWGDF 2019 update). Diabetes Metab Res Rev. 2020;36(Suppl 1):e3269.

Ahmed

Barwick

Butterworth

Nancarrow

. Footwear and insole design features that reduce neuropathic plantar forefoot ulcer risk in people with diabetes: a systematic literature review. J Foot Ankle Res. 2020;13(1):30.

Lopez-Moral

Lazaro-Martinez

Garcia-Morales

Garcia-Alvarez

Alvaro-Afonso

Molines-Barroso

. Clinical efficacy of therapeutic footwear with a rigid rocker sole in the prevention of recurrence in patients with diabetes mellitus and diabetic polineuropathy: a randomized clinical trial. PLoS One. 2019;14(7):e0219537.

Bus

Waaijman

Arts

, et al. Effect of custom-made footwear on foot ulcer recurrence in diabetes: A multicenter randomized controlled trial. Diabetes Care. 2013;36(12):4109-4116.

Lopez-Moral

Molines-Barroso

Alvaro-Afonso

Uccioli

Senneville

Lazaro-Martinez

. Importance of Footwear Outsole Rigidity in Improving Spatiotemporal Parameters in Patients with Diabetes and Previous Forefoot Ulcerations. J Clin Med. 2020;9(4).

Chapman

Preece

Braunstein

, et al. Effect of rocker shoe design features on forefoot plantar pressures in people with and without diabetes. Clin Biomech (Bristol, Avon). 2013;28(6):679-685.

Karimi

. The evaluation of foot rockers on the kinematic parameters of individuals with diabetes. Foot Ankle Spec. 2018;11(4):322-329.

Preece

Chapman

Braunstein

Bruggemann

Nester

. Optimisation of rocker sole footwear for prevention of first plantar ulcer: comparison of group-optimised and individually-selected footwear designs. J Foot Ankle Res. 2017;10:27.

10.

Alahakoon

Fernando

Galappaththy

, et al. Meta-analyses of randomized controlled trials reporting the effect of home foot temperature monitoring, patient education or offloading footwear on the incidence of diabetes-related foot ulcers. Diabet Med. 2020;37(8):1266-1279.

11.

Tang U

Zugner

Lisovskaja

Karlsson

Hagberg

Tranberg

. Comparison of plantar pressure in three types of insole given to patients with diabetes at risk of developing foot ulcers - A two-year, randomized trial. J Clin Transl Endocrinol. 2014;1(4):121-132.

12.

Paton

Glasser

Collings

Marsden

. Getting the right balance: Insole design alters the static balance of people with diabetes and neuropathy. J Foot Ankle Res. 2016;9:40.

13.

Dubsky

Jirkovska

Bem

, et al. Risk factors for recurrence of diabetic foot ulcers: Prospective follow-up analysis in the eurodiale subgroup. Int Wound J. 2013;10(5):555-561.

14.

Boulton

. Diabetic neuropathy and foot complications. Handb Clin Neurol. 2014;126:97-107.

15.

Ahmad

. The diabetic foot. Diabetes Metab Syndr. 2016;10(1):48-60.

16.

Edmonds

Blundell

Morris

Thomas

Cotton

Watkins

. Improved survival of the diabetic foot: the role of a specialized foot clinic. Q J Med. 1986;60(232):763-771.

17.

Ekpebegh

Iwuala

Fasanmade

Ogbera

Igumbor

Ohwovoriole

. Diabetes foot ulceration in a Nigerian hospital: in-hospital mortality in relation to the presenting demographic, clinical and laboratory features. Int Wound J. 2009;6(5):381-385.

18.

Ogbera

Osa

Edo

Chukwum

. Common clinical features of diabetic foot ulcers: perspectives from a developing nation. Int J Low Extrem Wounds. 2008;7(2):93-98.

19.

Macfarlane

Jeffcoate

. Factors contributing to the presentation of diabetic foot ulcers. Diabet Med. 1997;14(10):867-870.

20.

Harrison

Cochrane

Abboud

Leese

. Do patients with diabetes wear shoes of the correct size? Int J Clin Pract. 2007;61(11):1900-1904.

21.

McInnes

Hashmi

Farndon

, et al. Comparison of shoe-length fit between people with and without diabetic peripheral neuropathy: a case-control study. J Foot Ankle Res. 2012;5(1):9.

22.

Medical A

. World medical association declaration of Helsinki: ethical principles for medical research involving human subjects. JAMA. 2013;310(20):2191-2194.

23.

Jarl

Tranberg

Johansson

Alnemo

Lundqvist

. Predictors of adherence to wearing therapeutic footwear among people with diabetes. J Foot Ankle Res. 2020;13(1):45.

24.

Zhang

Yick

Yip

. Foot deformation analysis with different load-bearing conditions to enhance diabetic footwear designs. PLoS One. 2022;17(3):e0264233.

25.

van Netten

Bus

Apelqvist

, et al. Definitions and criteria for diabetic foot disease. Diabetes Metab Res Rev. 2020;36(Suppl 1):e3268.

26.

Lazaro-Martinez

Aragon-Sanchez

Alvaro-Afonso

Garcia-Morales

Garcia-Alvarez

Molines-Barroso

. The best way to reduce reulcerations: if you understand biomechanics of the diabetic foot, you can do it. Int J Low Extrem Wounds. 2014;13(4):294-319.

27.

Molines-Barroso

Lazaro-Martinez

Aragon-Sanchez

Alvaro-Afonso

Garcia-Morales

Garcia-Alvarez

. Forefoot ulcer risk is associated with foot type in patients with diabetes and neuropathy. Diabetes Res Clin Pract. 2016;114:93-98.

28.

van Netten

Jannink

Hijmans

Geertzen

Postema

. Use and usability of custom-made orthopedic shoes. J Rehabil Res Dev. 2010;47(1):73-81.

29.

Schaper

van Netten

Apelqvist

, et al. Practical guidelines on the prevention and management of diabetic foot disease (IWGDF 2019 update). Diabetes Metab Res Rev. 2020;36(1):e3266.

30.

Cohen

. A power primer. Psychol Bull. 1992;112(1):155-159.

31.

Novak

Mozina

Jezersek

. 3D laser measurements of bare and shod feet during walking. Gait Posture. 2014;40(1):87-93.

32.

Igiri

Tagang

Okoduwa

SIR

Adeyi

Okeh

. An integrative review of therapeutic footwear for neuropathic foot due to diabetes mellitus. Diabetes Metab Syndr. 2019;13(2):913-923.

33.

Bus

Armstrong

Gooday

, et al. Guidelines on offloading foot ulcers in persons with diabetes (IWGDF 2019 update). Diabetes Metab Res Rev. 2020;36(Suppl 1):e3274.

34.

Bus

Zwaferink

Dahmen

Busch-Westbroek

. State of the art design protocol for custom-made footwear for people with diabetes and peripheral neuropathy. Diabetes Metab Res Rev. 2019:e3237.

35.

Price

. How can we improve adherence? Diabetes Metab Res Rev. 2016;32(Suppl 1):201-205.

36.

Jarl

Lundqvist

. Adherence to wearing therapeutic shoes among people with diabetes: a systematic review and reflections. Patient Prefer Adherence. 2016;10:1521-1528.

37.

Hurst

Branthwaite

Greenhalgh

Chockalingam

. Medical-grade footwear: the impact of fit and comfort. J Foot Ankle Res. 2017;10:2.

38.

Menz

Morris

Lord

. Footwear characteristics and risk of indoor and outdoor falls in older people. Gerontology. 2006;52(3):174-180.

39.

Menz

Morris

. Footwear characteristics and foot problems in older people. Gerontology. 2005;51(5):346-351.

40.

Gershater

Londahl

Nyberg

, et al. Complexity of factors related to outcome of neuropathic and neuroischaemic/ischaemic diabetic foot ulcers: a cohort study. Diabetologia. 2009;52(3):398-407.

41.

Perrin

Raspovic

Williams

, et al. Establishing the national top 10 priority research questions to improve diabetes-related foot health and disease: a Delphi study of Australian stakeholders. BMJ Open Diabetes Res Care. 2021;9(2).