The role of foot pressure measurement in the prediction and prevention of diabetic foot ulceration-A comprehensive review

Testing protocols and measurement techniques when using pressure sensors for sport and health applications: A comparative review

Plantar pressure measurement systems are routinely used in sports and health applications to assess locomotion. The purpose of this review is to describe and critically discuss: (a) applications of the pressure measurement systems in sport and healthcare, (b) testing protocols and considerations for clinical gait analysis, (c) clinical recommendations for interpreting plantar pressure data, (d) calibration procedures and their accuracy, and (e) the future of pressure sensor data analysis. Rigid pressure platforms are typically used to measure plantar pressures for the assessment of foot function during standing and walking, particularly when barefoot, and are the most accurate for measuring plantar pressures. For reliable data, two step protocol prior to contacting the pressure plate is recommended. In-shoe systems are most suitable for measuring plantar pressures in the field during daily living or dynamic sporting movements as they are often wireless and can measure multiple steps. They are the most suitable equipment to assess the effects of footwear and orthotics on plantar pressures. However, they typically have lower spatial resolution and sampling frequency than platform systems. Users of pressure measurement systems need to consider the suitability of the calibration procedures for their chosen application when selecting and using a pressure measurement system. For some applications, a bespoke calibration procedure is required to improve validity and reliability of the pressure measurement system. The testing machines that are commonly used for dynamic calibration of pressure measurement systems frequently have loading rates of less than even those found in walking, so the development of testing protocols that truly measure the loading rates found in many sporting movements are required. There is clear potential for AI techniques to assist in the analysis and interpretation of plantar pressure data to enable the more complete use of pressure system data in clinical diagnoses and monitoring.

Differences in running biomechanics and tibiotalar cartilage T2 relaxation time between runners with and without asymptomatic tibial sesamoid bone marrow edema - clinical case series

The impact of asymptomatic bone marrow edema (BME) in sesamoids on running biomechanics remains largely unknown, but exploring this relationship could aid early detection of forefoot-related injuries with cost-effective modalities. This study aimed to compare the running biomechanics of runners with asymptomatic BME in the tibial sesamoids with that of healthy controls. Four runners with asymptomatic BME in tibial sesamoids and four healthy runners participated. Lower extremity joint kinetics and kinematics were assessed along with plantar pressure while running at a self-selected speed. The T2 relaxation time of the tibiotalar cartilage was measured using MRI-derived T2 maps. Compared to the non-injured group, the injured group exhibited significantly lower plantar pressure under the hallux (p = 0.001), increased peak ankle rotation angles (p = 0.025), reduced ankle power generation (p = 0.049), and increased knee extension torque (p = 0.015). No significant differences in T2 values of the tibiotalar cartilage were observed. It appears that runners with asymptomatic BME adapted their running strategies by modifying their ankle biomechanics and reducing plantar pressure, even in the absence of pain. While the precise implications of these biomechanical alterations warrant further investigation, this study provides valuable insights into the relationship between asymptomatic BME and running biomechanics.

A Multi-Faceted Digital Health Solution for Monitoring and Managing Diabetic Foot Ulcer Risk: A Case Series

INTRODUCTION

Diabetic foot ulcers (DFU) are a devastating complication of diabetes. There are numerous challenges with preventing diabetic foot complications and barriers to achieving the care processes suggested in established foot care guidelines. Multi-faceted digital health solutions, which combine multimodal sensing, patient-facing biofeedback, and remote patient monitoring (RPM), show promise in improving our ability to understand, prevent, and manage DFUs.

METHODS

Patients with a history of diabetic plantar foot ulcers were enrolled in a prospective cohort study and equipped with custom sensory insoles to track plantar pressure, plantar temperature, step count, and adherence data. Sensory insole data enabled patient-facing biofeedback to cue active plantar offloading in response to sustained high plantar pressures, and RPM assessments in response to data trends of concern in plantar pressure, plantar temperature, or sensory insole adherence. Three non-consecutive case participants that ultimately presented with pre-ulcerative lesions (a callus and/or erythematous area on the plantar surface of the foot) during the study were selected for this case series.

RESULTS

Across three illustrative patients, continuous plantar pressure monitoring demonstrated promise for empowering both the patient and provider with information for data-driven management of pressure offloading treatments.

CONCLUSION

Multi-faceted digital health solutions can naturally enable and reinforce the integrative foot care guidelines. Multi-modal sensing across multiple physiologic domains supports the monitoring of foot health at various stages along the DFU pathogenesis pathway. Furthermore, digital health solutions equipped with remote patient monitoring unlock new opportunities for personalizing treatments, providing periodic self-care reinforcement, and encouraging patient engagement-key tools for improving patient adherence to their diabetic foot care plan.

Plantar pressure measurement in diabetic foot disease: A scoping review

AIMS/INTRODUCTION

Patients with a healed diabetic foot ulcer (DFU) have a 40% risk of ulcer recurrence within a year. New and effective measures to prevent DFU recurrence are essential. We aimed to highlight emerging trends and future research opportunities in the use of plantar pressure measurement to prevent DFU recurrence.

MATERIALS AND METHODS

Our scoping review protocol was drafted using the Preferred Reporting Items for Systematic Reviews and Meta-analysis - Scoping Review protocol. Peer-reviewed, English-language papers were included that addressed both plantar pressure measurement and diabetic foot disease, either as primary studies that have advanced the field or as review papers that provide summaries and/or opinion on the field as a whole, as well as specific papers that provide guidelines for future research and advancement in the field.

RESULTS

A total of 24 eligible publications were identified in a literature search using PubMed. A further 36 eligible studies were included after searching the references sections of these publications, leaving a total of 60 publications included in this scoping review.

CONCLUSIONS

Plantar pressure measurement can and will play a major role in the prevention of DFU. There is already a strong, albeit limited, evidence base in place to prove its benefit in reducing DFU recurrence. More research is required in larger populations, using remote monitoring in real-world settings, and with improved technology.

Identification and analysis of prognostic metabolic characteristics in colon adenocarcinoma

Colon adenocarcinoma (COAD) is a highly lethal gastrointestinal malignancy. The five-year survival rate of metastatic colorectal cancer remains low, at 14 percent. Numerous publications have suggested a role for peroxisome proliferator-activated receptors (PPARs) in malignancy. Recent studies have shown that PPARs, as nuclear transcription factors, may serve as potential targets for the treatment of metabolic syndrome tumors and their associated complications. However, the molecular mechanism has not been thoroughly investigated. Hence, in order to enhance the prediction of personalized medicine for PPAR-associated modulators in malignancy treatment, a timely review becomes essential. Utilizing TCGA-COAD expression profile data and patient overall survival (OS) information, this study systematically conducted investigations to identify and develop Hub stem cell-related diagnostic and prognostic identification models, aiming to enhance the multi-gene markers for COAD. Utilizing the differential expression profiles of stem cell-related genes, an 11-gene (SLC27A4, CPT1C, CPT1B, CPT2, CYP4A11, FABP3, FABP7, AQP7, MMP1, ACOX1, ANGPTL4) diagnostic and prognostic model was developed. This model demonstrated precise diagnostic and prognostic capabilities and holds the potential to characterize the clinicopathologic features of COAD. Univariate and multivariate Cox proportional hazards regression analyses were conducted to ascertain the independent factors influencing OS outcomes in COAD. The results revealed that CPT1B, SLC27A4, and FABP3 were identified as independent risk prognostic factors for OS in COAD, whereas ACOX1 and CPT2 served as independent protective prognostic factors. The hub genes associated with PPARs were identified through the differential expression of contrast agent COAD and normal tissues. Finally, the investigation of variations in immune infiltration and the analysis of relevant biological pathways validate the prognostic significance of the independent post-factors within this molecular model. This research aims to provide references for comprehending the mechanism of post-transcriptional regulation of COAD and molecular therapy.

HMOX1 as a therapeutic target associated with diabetic foot ulcers based on single-cell analysis and machine learning

Diabetic foot ulcers (DFUs) are a serious chronic complication of diabetes mellitus and a leading cause of disability and death in diabetic patients. However, current treatments remain unsatisfactory. Although macrophages are associated with DFU, their exact role in this disease remains uncertain. This study sought to detect macrophage-related genes in DFU and identify possible therapeutic targets. Single-cell datasets (GSE223964) and RNA-seq datasets (GSM68183, GSE80178, GSE134431 and GSE147890) associated with DFU were retrieved from the gene expression omnibus (GEO) database for this study. Analysis of the provided single-cell data revealed the distribution of macrophage subpopulations in the DFU. Four independent RNA-seq datasets were merged into a single DFU cohort and further analysed using bioinformatics. This included differential expression (DEG) analysis, multiple machine learning algorithms to identify biomarkers and enrichment analysis. Finally, key results were validated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western bolt. Finally, the findings were validated using RT-qPCR and western blot. We obtained 802 macrophage-related genes in single-cell analysis. Differential expression analysis yielded 743 DEGs. Thirty-seven macrophage-associated DEGs were identified by cross-analysis of marker genes with macrophage-associated DEGs. Thirty-seven intersections were screened and cross-analysed using four machine learning algorithms. Finally, HMOX1 was identified as a potentially valuable biomarker. HMOX1 was significantly associated with biological pathways such as the insulin signalling pathway. The results showed that HMOX1 was significantly overexpressed in DFU samples. In conclusion, the analytical results of this study identified HMOX1 as a potentially valuable biomarker associated with macrophages in DFU. The results of our analysis improve our understanding of the mechanism of macrophage action in this disease and may be useful in developing targeted therapies for DFU.

Prevention of foot ulcers in persons with diabetes at risk of ulceration: A systematic review and meta-analysis

AIMS

Prevention of foot ulcers in persons with diabetes is important to help reduce the substantial burden on both individual and health resources. A comprehensive analysis of reported interventions is needed to better inform healthcare professionals about effective prevention. The aim of this systematic review and meta-analysis is to assess the effectiveness of interventions to prevent foot ulcers in persons with diabetes who are at risk thereof.

MATERIALS AND METHODS

We searched the available scientific literature in PubMed, EMBASE, CINAHL, Cochrane databases and trial registries for original research studies on preventative interventions. Both controlled and non-controlled studies were eligible for selection. Two independent reviewers assessed risk of bias of controlled studies and extracted data. A meta-analysis (using Mantel-Haenszel's statistical method and random effect models) was done when >1 RCT was available that met our criteria. Evidence statements, including the certainty of evidence, were formulated according to GRADE.

RESULTS

From the 19,349 records screened, 40 controlled studies (of which 33 were Randomised Controlled Trials [RCTs]) and 103 non-controlled studies were included. We found moderate certainty evidence that temperature monitoring (5 RCTs; risk ratio [RR]: 0.51; 95% CI: 0.31-0.84) and pressure-optimised therapeutic footwear or insoles (2 RCTs; RR: 0.62; 95% CI: 0.26-1.47) likely reduce the risk of plantar foot ulcer recurrence in people with diabetes at high risk. Further, we found low certainty evidence that structured education (5 RCTs; RR: 0.66; 95% CI: 0.37-1.19), therapeutic footwear (3 RCTs; RR: 0.53; 95% CI: 0.24-1.17), flexor tenotomy (1 RCT, 7 non-controlled studies, no meta-analysis), and integrated care (3 RCTs; RR: 0.78; 95% CI: 0.58-1.06) may reduce the risk of foot ulceration in people with diabetes at risk for foot ulceration.

CONCLUSIONS

Various interventions for persons with diabetes at risk for foot ulceration with evidence of effectiveness are available, including temperature monitoring (pressure-optimised) therapeutic footwear, structured education, flexor tenotomy, and integrated foot care. With hardly any new intervention studies published in recent years, more effort to produce high-quality RCTs is urgently needed to further improve the evidence base. This is especially relevant for educational and psychological interventions, for integrated care approaches for persons at high risk of ulceration, and for interventions specifically targeting persons at low-to-moderate risk of ulceration.

Synergistic advancements in high-performance flexible capacitive pressure sensors: structural modifications, AI integration, and diverse applications

The development of flexible pressure sensors for monitoring human motion and physiological signals has attracted extensive scientific research. However, achieving low monitoring limits, a wide detection range, large bending stresses, and excellent mechanical stability simultaneously remains a serious challenge. With the aim of developing a high-performance capacitive pressure sensor (CPS), this paper introduces the successful preparation of a single-walled carbon nanotube (SWNT)/polydimethylsiloxane (S-PDMS) composite dielectric with a foam-like structure (high permittivity and low elasticity modulus) and MXene/SWNT (S-MXene) composite film electrodes with a micro-crumpled structure. The above structurally modified CPS (SMCPS) demonstrated an excellent response output during pressure loading, achieving a wide pressure detection range (up to 700 kPa), a low detection limit (16.55 Pa), fast response/recovery characteristics (48/60 ms), enhanced sensitivity across a wide pressure range, long-term stability under repeated heavy loading and unloading (40 kPa, >2000 cycles), and reliable performance under various temperature and humidity conditions. The SMCPS demonstrated a precise and stable capacitive response in monitoring subtle physiological signals and detecting motion, owing to its unique electrode structure. The flexible device was integrated with an Internet of Things module to create a smart glove system that enables real-time tracking of dynamic gestures. This system demonstrates exceptional performance in gesture recognition and prediction with artificial intelligence analysis, highlighting the potential of the SMCPS in human-machine interface applications.

Foot Plantar Pressure Abnormalities in Near Adulthood Patients with Type 1 Diabetes

Increased ulcer risk diminishes the quality of life in diabetes. This study assessed abnormalities in foot plantar pressure distribution in adolescents with T1D to detect early signs of ulcer risk. A total of 102 T1D patients, without diabetic neuropathy, were included (mean age 17.8 years, mean diabetes duration 7.4 year). Pedography was captured using Novel emed. Data from the study group were compared with reference data. The study revealed a statistically significant reduced foot contact area in both feet in the entire foot and under the head of the fifth metatarsal bone and the second toe. In both feet, the peak pressure was increased under the entire foot, hindfoot, midfoot, first metatarsal head, big toe, and second toe. There was no statistically significant difference in peak pressure. The mean plantar pressure rating was statistically significantly increased in both feet across the entire sole, in the hindfoot, midfoot, and first metatarsal head. T1D patients of age near adulthood without neuropathy have increased values in mean pressure and reduced contact area, pointing to the need of monitoring and preventive measures. These results point to the need of further research and analysis which should include various risk factor such as foot anatomy, body posture, or certain metabolic factors.

Effective and clinically relevant optimisation of cushioning stiffness to maximise the offloading capacity of diabetic footwear

INTRODUCTION

Optimising the cushioning stiffness of diabetic footwear/orthoses can significantly enhance their offloading capacity. This study explores whether optimum cushioning stiffness can be predicted using simple demographic and anthropometric parameters.

METHODS

Sixty-nine adults with diabetes and loss of protective sensation in their feet were recruited for this cross-sectional observational study. In-shoe plantar pressure was measured using Pedar® for a neutral diabetic shoe (baseline) and after adding cushioning footbeds of varying stiffness. The cushioning stiffness that achieved maximum offloading was identified for each participant. The link between optimum cushioning stiffness and plantar loading or demographic/anthropometric parameters was assessed using multinomial regression.

RESULTS

People with higher baseline plantar loading required stiffer cushioning materials for maximum offloading. Using sex, age, weight, height, and shoe-size as covariates correctly predicted the cushioning stiffness that minimised peak pressure across the entire foot, or specifically in the metatarsal heads, midfoot and heel regions in 70%, 72%, 83% and 66% of participants respectively.

CONCLUSIONS

Increased plantar loading is associated with the need for stiffer cushioning materials for maximum offloading. Patient-specific optimum cushioning stiffness can be predicted using five simple demographic/anthropometric parameters. These results open the way for methods to optimise cushioning stiffness as part of clinical practice.

Evaluation of in-shoe plantar pressure and shear during walking for diabetic foot ulcer prevention

OBJECTIVE

To investigate reliability and changes of in-shoe plantar pressure and shear during walking at three cadences with two insole designs. This was a precursor to the investigation of plantar loading in people with diabetes for potential foot ulcer prevention.

METHOD

A sensorised insole system, capable of measuring plantar pressure and shear at the heel, fifth metatarsal head (5MH), first metatarsal head (1MH) and hallux, was tested with ten healthy participants during level walking. Reliability was evaluated, using intra-class correlation coefficient (ICC), while varying the cadences and insole types. Percentage changes in pressure and shear relative to values obtained at self-selected cadence with a flat insole design were investigated.

RESULTS

Mean±standard deviation of maximum pressure, medial-lateral and anterior-posterior shear of up to 380±24kPa, 46±2kPa and -71±4kPa, respectively, were measured. The ICC in ranges of 0.762-0.973, 0.758-0.987 and 0.800-0.980 were obtained for pressure, anterior-posterior and medial-lateral shear, respectively. Opposite anterior-posterior shear directions between 5MH and 1MH (stretching), and between 1MH and hallux (pinching) were observed for some participants. Increasing cadence increased pressure and anterior-posterior shear (by up to +77%) but reduced medial-lateral shear at the heel and hallux (by up to -34%). Slower cadence increased anterior-posterior shear (+114%) but decreased medial-lateral shear (-46%) at the hallux. The use of a flexible contoured insole resulted in pressure reduction at the heel and 5MH but an increase in anterior-posterior shear at the heel (+69%) and hallux (+75%).

CONCLUSION

The insole system demonstrated good reliability and is comparable to reported pressure-only systems. Pressure measurements were sensitive to changes in cadence and insole designs in ways that were consistent with the literature. However, our plantar shear showed localised shear changes with cadences and insoles for the first time, as well as stretching and pinching effects on plantar tissue. This opens new possibilities to investigate plantar tissue viability, loading characteristics and orthotic designs aimed towards foot ulcer prevention.

Preventative Sensor-Based Remote Monitoring of the Diabetic Foot in Clinical Practice

Diabetes and its complications, particularly diabetic foot ulcers (DFUs), pose significant challenges to healthcare systems worldwide. DFUs result in severe consequences such as amputation, increased mortality rates, reduced mobility, and substantial healthcare costs. The majority of DFUs are preventable and treatable through early detection. Sensor-based remote patient monitoring (RPM) has been proposed as a possible solution to overcome limitations, and enhance the effectiveness, of existing foot care best practices. However, there are limited frameworks available on how to approach and act on data collected through sensor-based RPM in DFU prevention. This perspective article offers insights from deploying sensor-based RPM through digital DFU prevention regimens. We summarize the data domains and technical architecture that characterize existing commercially available solutions. We then highlight key elements for effective RPM integration based on these new data domains, including appropriate patient selection and the need for detailed clinical assessments to contextualize sensor data. Guidance on establishing escalation pathways for remotely monitored at-risk patients and the importance of predictive system management is provided. DFU prevention RPM should be integrated into a comprehensive disease management strategy to mitigate foot health concerns, reduce activity-associated risks, and thereby seek to be synergistic with other components of diabetes disease management. This integrated approach has the potential to enhance disease management in diabetes, positively impacting foot health and the healthspan of patients living with diabetes.

A scientometrics analysis and visualisation of diabetic foot research from 1955 to 2022

Diabetic foot (DF) has become a serious health problem in modern society, and it has been a hotspot of research for a long time. However, little scientometric analysis has been carried out on DF. In the present study, we analysed 8633 literature reports on DF in the Web of Science Core Collection from database inception until April 23, 2022. VOSviewer (Centre for Science and Technology Studies at Leiden University, Leiden, the Netherlands) and CiteSpace (College of Computing and Informatics, Drexel University, Philadelphia, United States) were employed to address high-impact countries and institutions, journals, references, research hotspots, and key research fields in DF research. Our analysis findings indicated that publications on DF have increased markedly since 2016 and were primarily published in the United States of America. The recent studies focus on the amniotic membrane, foot ulcers, osteomyelitis, and diabetic wound healing. The five keyword clusters, which included DF ulcer and wound healing therapies, management and guidelines, neuropathy and plantar pressure, amputation and ischemia, and DF infection and osteomyelitis, are helpful for enhancing prevention, standardising treatment, avoiding complications, and improving prognosis. These findings indicated a method for future therapies and research in DF.

A Wearable Insole System to Measure Plantar Pressure and Shear for People with Diabetes

Pressure coupled with shear stresses are the critical external factors for diabetic foot ulceration assessment and prevention. To date, a wearable system capable of measuring in-shoe multi-directional stresses for out-of-lab analysis has been elusive. The lack of an insole system capable of measuring plantar pressure and shear hinders the development of an effective foot ulcer prevention solution that could be potentially used in a daily living environment. This study reports the development of a first-of-its-kind sensorised insole system and its evaluation in laboratory settings and on human participants, indicating its potential as a wearable technology to be used in real-world applications. Laboratory evaluation revealed that the linearity error and accuracy error of the sensorised insole system were up to 3% and 5%, respectively. When evaluated on a healthy participant, change in footwear resulted in approximately 20%, 75% and 82% change in pressure, medial-lateral and anterior-posterior shear stress, respectively. When evaluated on diabetic participants, no notable difference in peak plantar pressure, as a result of wearing the sensorised insole, was measured. The preliminary results showed that the performance of the sensorised insole system is comparable to previously reported research devices. The system has adequate sensitivity to assist footwear assessment relevant to foot ulcer prevention and is safe to use for people with diabetes. The reported insole system presents the potential to help assess diabetic foot ulceration risk in a daily living environment underpinned by wearable pressure and shear sensing technologies.

Does in-shoe pressure analysis to assess and modify medical grade footwear improve patient adherence and understanding? A mixed methods study

BACKGROUND

Medical grade footwear (MGF) with demonstrated plantar-pressure reducing effect is recommended to reduce the risk of diabetes-related foot ulceration (DFU). Efficacy of MGF relies on high adherence (≥ 80%). In-shoe pressure analysis (IPA) is used to assess and modify MGF, however, there is limited evidence for the impact on patient adherence and understanding of MGF. The primary aim of this study was to determine if self-reported adherence to MGF usage in patients with previous DFU improved following IPA compared to adherence measured prior. The secondary aim was to determine if patient understanding of MGF improved following in-shoe pressure analysis.

METHODS

Patients with previous DFU fitted with MGF in the last 12 months were recruited. The first three participants were included in a pilot study to test procedures and questionnaires. MGF was assessed and modified at Week 0 based on findings from IPA using the Pedar system (Novel). Patients completed two questionnaires, one assessing patient adherence to MGF at Week 0 and Week 4, the other assessing patient understanding of MGF before and after IPA at week 0. Patient understanding was measured using a 5-point Likert scale (strongly disagree 1 to strongly agree 5). Patient experience was assessed via a telephone questionnaire administered between Weeks 0-1.

RESULTS

Fifteen participants were recruited, and all completed the study. Adherence of ≥ 80% to MGF usage inside the home was 13.3% (n = 2) pre-IPA and 20.0% (n = 3) at Week 4. Outside the home, ≥ 80% adherence to MGF was 53.3% (n = 8) pre-IPA, and 80.0% (n = 12) at Week 4. Change in scores for understanding of MGF were small, however, all participants reported that undergoing the intervention was worthwhile and beneficial.

CONCLUSIONS

Self-reported adherence inside the home demonstrated minimal improvement after 4 weeks, however, adherence of ≥ 80% outside the home increased by 27%, with 80% of all participants reporting high adherence at Week 4. Participants rated their learnings from the experience of IPA as beneficial.

Artificial Intelligence Methodologies Applied to Technologies for Screening, Diagnosis and Care of the Diabetic Foot: A Narrative Review

Diabetic foot syndrome is a multifactorial pathology with at least three main etiological factors, i.e., peripheral neuropathy, peripheral arterial disease, and infection. In addition to complexity, another distinctive trait of diabetic foot syndrome is its insidiousness, due to a frequent lack of early symptoms. In recent years, it has become clear that the prevalence of diabetic foot syndrome is increasing, and it is among the diabetes complications with a stronger impact on patient's quality of life. Considering the complex nature of this syndrome, artificial intelligence (AI) methodologies appear adequate to address aspects such as timely screening for the identification of the risk for foot ulcers (or, even worse, for amputation), based on appropriate sensor technologies. In this review, we summarize the main findings of the pertinent studies in the field, paying attention to both the AI-based methodological aspects and the main physiological/clinical study outcomes. The analyzed studies show that AI application to data derived by different technologies provides promising results, but in our opinion future studies may benefit from inclusion of quantitative measures based on simple sensors, which are still scarcely exploited.

Vitamin C and the management of diabetic foot ulcers: a literature review

OBJECTIVE

The lifetime risk of developing a diabetic foot ulcer (DFU) in people with diabetes is as high as 25%. A trio of factors constitute the diabetic foot syndrome that characterises DFUs, including neuropathy, vascular disease and infections. Vitamin C has important functions in the nervous, cardiovascular, and immune systems that are implicated in DFU development. Furthermore, vitamin C deficiency has been observed in individuals with DFUs, suggesting an important function of vitamin C in DFU management and treatment. Therefore, this literature review evaluates the role of vitamin C in the nervous, cardiovascular and immune systems in relation to wound healing and DFUs, as well as discussing vitamin C's lesser known role in depression, a condition that affects many individuals with a DFU.

METHOD

A literature search was done using PubMed, Cochrane Library, Embase, Ovid, Computer Retrieval of Information on Scientific Projects, and NIH Clinical Center. Search terms included 'diabetic foot ulcer,' 'diabetic foot,' 'vitamin C,' and 'ascorbic acid.'

RESULTS

Of the 71 studies initially identified, seven studies met the inclusion criteria, and only three were human clinical trials. Overall, the literature on this subject is limited, with mainly observational and animal studies, and few human clinical trials.

CONCLUSION

There is a need for additional human clinical trials on vitamin C supplementation in individuals with a DFU to fill the knowledge gap and guide clinical practice.

A novel graded-stiffness footwear device for heel ulcer prevention and treatment: a finite element-based study

Diabetic heel ulceration is a serious, destructive, and costly complication of diabetes. In this study, a novel "graded-stiffness" offloading method was proposed. This method consists of heel support with multi-increasing levels of stiffness materials, to prevent and treat heel ulcers. A three-dimensional finite element model of the heel was used to evaluate the novel "graded-stiffness" orthotic device compared to two existing solutions: (1) an insole with a hole under the active ulcer and (2) an insole with a hole filled with a soft material (elastic modulus of 15 kPa). Volumetric exposure evaluation of internal tissues to stress was performed at two volume-of-interests: (1) the area of the heel soft tissues typically at high risk for ulceration, and (2) the soft tissues surrounding the high-risk area. The models predict that the "graded-stiffness" offloading solution is more effective than existing solutions in distributing and reducing heel internal loads, considering both volume-of-interests. Comparing different material gradient combinations for the offloading support reveals considerable variation of the heel stress distribution. In clinical practice, the "graded-stiffness" technological solution enables to form an adaptable and flexible system that can be customized to a specific patient, through adequate selection of the offloading materials, to fit the shape and size of the ulcer. This solution can be made as an off-the-shelf product or alternatively, be manufactured by-demand using 3D printing tools. The proposed novel practical offloading solution has the potential for streamlining and optimizing the prevention and treatment of diabetic heel ulcers.

Smart Insole Based on Flexi Force and Flex Sensor for Monitoring Different Body Postures

This study aims to fabricate smart insoles using wireless Flexi force and bend sensing technology. Polyvinyl chloride (PVC) film was chosen as the substrate to hold all the sensors. The developed smart insole has a three-layer structure (insole-PVC layer-fabric layer) and is calibrated in an isolation laboratory to evaluate its measurement performance. One male volunteer subject exhibited four different body postures, namely tree pose, forward-leaning, squatting, and forward folding pose. Changes in pressure distribution were considered to be similar for the forward, squat, and forward-folded positions. When subjects performed a full squat, the flex sensor exhibited maximum flexion during the squat position, and the flex sensor response against the squat pose was found to be higher by about 18.18% than in the forward lean, respectively. The tree pose has the highest error rate at the first metatarsal, about 18.6%, of which the maximum absolute relative error of the sensor is less than 5%. Plantar pressure distribution and body posture measurements were successfully validated using Flexi force and flex sensors embedded in the smart insole. The smart insole proposed in this research work has broader prospects for clinical application.

Diabetes mellitus and diabetic foot ulcer: Etiology, biochemical and molecular based treatment strategies via gene and nanotherapy

Diabetes mellitus (DM) is a collection of metabolic and pathophysiological disorders manifested with high glucose levels in the blood due to the inability of β-pancreatic cells to secrete an adequate amount of insulin or insensitivity of insulin towards receptor to oxidize blood glucose. Nevertheless, the preceding definition is only applicable to people who do not have inherited or metabolic disorders. Suppose a person who has been diagnosed with Type 1 or Type 2DM sustains an injury and the treatment of the damage is complicated and prolonged. In that case, the injury is referred to as a diabetic foot ulcer (DFU). In the presence of many proliferating macrophages in the injury site for an extended period causes the damage to worsen and become a diabetic wound. In this review, the scientific information and therapeutic management of DM/DFU with nanomedicine, and other related data were collected (Web of Science and PubMed) from January 2000 to January 2022. Most of the articles revealed that standard drugs are usually prescribed along with hypoglycaemic medications. Conversely, such drugs stabilize the glucose transporters and homeostasis for a limited period, resulting in side effects such as kidney damage/failure, absorption/gastrointestinal problems, and hypoglycemic issues. In this paper, we review the current basic and clinical evidence about the potential of medicinal plants, gene therapy, chemical/green synthesized nanoparticles to improving the metabolic profile, and facilitating the DM and DFU associated complications. Preclinical studies also reported lower plasma glucose with molecular targets in DM and DFU. Research is underway to explore chemical/green synthesized nanoparticle-based medications to avoid such side effects. Hence, the present review is intended to address the current challenges, recently recognized factors responsible for DM and DFU, their pathophysiology, insulin receptors associated with DM, medications in trend, and related complications.

Relationship Between Plantar Tissue Hardness and Plantar Pressure Distributions in People With Diabetic Peripheral Neuropathy

Objective: People with diabetic peripheral neuropathy (DPN) are usually accompanied with increased plantar pressure. Such high plantar loading during daily activities may cause changes in the biomechanical properties of plantar soft tissue, whose viability is critical to the development of foot ulcers. This study aimed to investigate the relationship between plantar tissue hardness and plantar pressure in people with and without DPN, and preliminarily explore the influence of plantar loading patterns on the plantar pressure and tissue hardness.

Methods: The study was conducted on 14 people with DPN and 14 diabetic people without DPN. The Shore durometer and MatScan System were used to measure the plantar tissue hardness and plantar pressure, respectively. The plantar loading level was evaluated by the duration of daily weight-bearing activity and was used to group diabetic participants with and without DPN into two subgroups (lower loading group and higher loading group).

Results: The plantar tissue hardness was significantly correlated with static peak plantar pressure (PPP, p < 0.05) and dynamic pressure-time integral (PTI, p < 0.05) in the forefoot region in people with DPN. Results of variance analysis showed a significant interaction effect between peripheral neuropathy and plantar loading on tissue hardness (p < 0.05), but not plantar pressure. For people with DPN, significant differences in tissue hardness between the higher loading group and lower loading group were observed in the forefoot, midfoot and hindfoot regions. In the higher loading group, people with DPN had significantly greater tissue hardness than that in people without DPN in the toes, forefoot, midfoot and hindfoot regions (p < 0.05).

Conclusions: There is a significant correlation between tissue hardness and PPP, and between tissue hardness and PTI in people with DPN. Plantar loading associated with daily activities plays a significant role on the plantar tissue hardness in people with DPN. The findings of this study contribute to further understand the relationship between increased plantar tissue hardness and high plantar pressure in people with diabetic peripheral neuropathy.

Site-Specific, Critical Threshold Barefoot Peak Plantar Pressure Associated with Diabetic Foot Ulcer History: A Novel Approach to Determine DFU Risk in the Clinical Setting

Background and Objectives: Barefoot peak plantar pressures (PPPs) are elevated in diabetes patients with neuropathic foot ulcer (DFU) history; however, there is limited reported evidence for a causative link between high barefoot PPP and DFU risk. We aimed to determine, using a simple mat-based methodology, the site-specific, barefoot PPP critical threshold that will identify a plantar site with a previous DFU. Materials and Methods: In a cross-sectional study, barefoot, site-specific PPPs were measured with normal gait for patients with DFU history (n = 21) and healthy controls (n = 12), using a validated carbon footprint system. For each participant, PPP was recorded at twelve distinct plantar sites (1st–5th toes, 1st–5th metatarsal heads (MTHs), midfoot and heel), per right and left foot, resulting in the analysis of n = 504 distinct plantar sites in the diabetes group, and n = 288 sites in the control group. Receiver operator characteristic curve analysis determined the optimal critical threshold for sites with DFU history. Results: Median PPPs for the groups were: diabetes sites with DFU history (n = 32) = 5.0 (3.25–7.5) kg/cm², diabetes sites without DFU history (n = 472) = 3.25 (2.0–5.0) kg/cm², control sites (n = 288) = 2.0 (2.0–3.25) kg/cm²; (p < 0.0001). Diabetes sites with elevated PPP (>6 kg/cm²) were six times more likely to have had DFU than diabetes sites with PPP ≤ 6 kg/cm² (OR = 6.4 (2.8–14.6, 95% CI), p < 0.0001). PPP > 4.1 kg/cm² was determined as the optimal critical threshold for identifying DFU at a specific plantar site, with sensitivity/specificity = 100%/79% at midfoot; 80%/65% at 5th metatarsal head; 73%/62% at combined midfoot/metatarsal head areas. Conclusions: We have demonstrated, for the first time, a strong, site-specific relationship between elevated barefoot PPP and previous DFU. We have determined a critical, highly-sensitive, barefoot PPP threshold value of >4.1 kg/cm², which may be easily used to identify sites of previous DFU occurrence and, therefore, increased risk of re-ulceration. This site-specific approach may have implications for how high PPPs should be investigated in future trials.

Plantar pressure during gait: norm-referenced measurement for Brazilian healthy adults using the Footwork Pro® System

Abstract Introduction The measurement of plantar pressure is an important component in the evaluation of the locomotive system. However, the absence of norm-referenced measurement poses limitations to its use. Objective To verify the influence of gender on plantar pressure during gait in healthy adults and to propose norm-referenced measurement that may be used as a reference for monitoring. Methods The study included 353 healthy participants (158 females and 195 males), aged between 20 and 64 years, and with a normal foot posture. Using a pressure platform, the peak plantar pressure and pressure-time integrals were measured in three areas of the foot: forefoot, midfoot, and hindfoot. Results Both indicators of plantar pressure showed no significant differences between genders (p ≤ 0.05). Higher peak plantar pressure was found in the forefoot region, while a higher pressure-time integral was found in the hindfoot region. Percentile distribution values were made available for the data set of females and males. Conclusion The available norm-referenced measurement may be used to identify pathological gait parameters, monitor the efficacy of therapeutic interventions, and detect individuals in need of referral for a more sophisticated and detailed evaluation.

Early diagnosis of diabetic peripheral neuropathy based on infrared thermal imaging technology

AIMS

The purpose of this study was to detect and compare the surface temperature of plantar vessels in mild diabetic peripheral neuropathy (DPN) patients and healthy controls, to explore a simple, convenient and reliable method for early diagnosis of DPN, and to explore the influence of sex and age on vascular surface temperature.

MATERIALS AND METHODS

In this study, 60 mild DPN patients (30 males and 30 females) and 60 healthy volunteers were randomly recruited according to their age and sex. Intra-class correlation coefficient was used to evaluate the repeatability of skin temperature measurement in the vascular area. A general linear model was used to analyse the difference of skin temperature between mild DPN patients and healthy controls.

RESULTS

The infrared detection results of skin temperature corresponding to blood vessels showed excellent test-retest reliability. There was no significant difference in skin temperature between sex and age. But there were significant differences in skin temperature between mild DPN patients and healthy controls, except for the posterior tibial artery.

CONCLUSIONS

For mild DNP patients, in case of no obvious abnormality in the infrared detection of lower extremity arterial surface temperature, the small vessels have shown early abnormal body surface temperature, that is, the surface temperature of related vessels increased. The research conclusions of this article not only enable us to better understand the correlation between body surface temperature and hemodynamic parameters, but also provide an in vivo, non-invasive, and convenient way of thinking and methods for early diagnosis of DPN.

Flexible Ultra-Thin Nanocomposite Based Piezoresistive Pressure Sensors for Foot Pressure Distribution Measurement

Foot pressure measurement plays an essential role in healthcare applications, clinical rehabilitation, sports training and pedestrian navigation. Among various foot pressure measurement techniques, in-shoe sensors are flexible and can measure the pressure distribution accurately. In this paper, we describe the design and characterization of flexible and low-cost multi-walled carbon nanotubes (MWCNT)/Polydimethylsiloxane (PDMS) based pressure sensors for foot pressure monitoring. The sensors have excellent electrical and mechanical properties an show a stable response at constant pressure loadings for over 5000 cycles. They have a high sensitivity of 4.4 kΩ/kPa and the hysteresis effect corresponds to an energy loss of less than 1.7%. The measurement deviation is of maximally 0.13% relative to the maximal relative resistance. The sensors have a measurement range of up to 330 kPa. The experimental investigations show that the sensors have repeatable responses at different pressure loading rates (5 N/s to 50 N/s). In this paper, we focus on the demonstration of the functionality of an in-sole based on MWCNT/PDMS nanocomposite pressure sensors, weighing approx. 9.46 g, by investigating the foot pressure distribution while walking and standing. The foot pressure distribution was investigated by measuring the resistance changes of the pressure sensors for a person while walking and standing. The results show that pressure distribution is higher in the forefoot and the heel while standing in a normal position. The foot pressure distribution is transferred from the heel to the entire foot and further transferred to the forefoot during the first instance of the gait cycle.

Associations between changes in loading pattern, deformity, and internal stresses at the foot with hammer toe during walking; a finite element approach

Over the past decade, Finite Element (FE) modelling has been used as a method to understand the internal stresses within the diabetic foot. Foot deformities such as hammer toe have been associated with increased risk of foot ulcers in diabetic patients. Hence the aim of this study is to investigate the influence of hammer toe deformity on internal stresses during walking. A 3D finite element model of the human foot was constructed based on capturing Magnetic Resonance Imaging (MRI) of a diabetic neuropathic volunteer exhibiting hammer toe. 3D gait measurements and a multi-body musculoskeletal model for the same participant were used to define muscle forces. FE simulations were run at five different instances during the stance phase of gait. Peak plantar pressure and pressure distribution results calculated from the model showed a good agreement with the experimental measurement having less than 11% errors. Maximum von Mises internal stresses in the forefoot hard tissue were observed at the 3^rd and 5^th metatarsals and 4^th proximal phalanx. Moreover, presence of hammer toe deformity was found to shift the location of maximum internal stresses on the soft tissue to the forefoot by changing the location of centre of pressure with internal stress 1.64 times greater than plantar pressure. Hammer toe deformity also showed to reduce the involvement of the first phalanx in internal/external load-bearing during walking. The findings of this study support the association between changes in loading pattern, deformity, and internal stresses in the soft tissue that lead to foot ulceration.

The effects of different accumulated pressure-time integral stimuli on plantar blood flow in people with diabetes mellitus

Background

Exercise, especially weight-bearing exercise (e.g. walking), may affect plantar tissue viability due to prolonged repetitive high vertical and high shear pressure stimulus on the plantar tissue, and further induce development of diabetic foot ulcers (DFUs). This study aimed to investigate the effects of different accumulated pressure-time integral (APTI) stimuli induced by walking on plantar skin blood flow (SBF) responses in people with diabetes mellitus (DM).

Methods

A repeated measures design was used in this study. Two walking protocols (low APTI (73,000 kPa·s) and high APTI (73,000 × 1.5 kPa·s)) were randomly assigned to ten people with DM and twenty people without DM. The ratio of SBF measured by laser Doppler flowmetry after walking to that before (normalized SBF) was used to express the SBF responses.

Results

After low APTI, plantar SBF of people with DM showed a similar response to people without DM (P = 0.91). However, after high APTI, people with DM had a significantly lower plantar SBF compared to people without DM (P < 0.05). In people with DM, plantar SBF in the first 2 min after both APTI stimuli significantly decreased compared to plantar SBF before walking (P < 0.05).

Conclusions

People with DM had a normal SBF response after low APTI walking but had an impaired SBF response after high APTI walking, which suggests that they should avoid weight-bearing physical activity with intensity more than 73,000 kPa·s and should rest for more than 2 min after weight-bearing physical activity to allow a full vasodilatory response to reduce risk of DFUs.

A novel concept for low-cost non-electronic detection of overloading in the foot during activities of daily living

Identifying areas in the sole of the foot which are routinely overloaded during daily living is extremely important for the management of the diabetic foot. This work showcases the feasibility of reliably detecting overloading using a low-cost non-electronic technique. This technique uses thin-wall structures that change their properties differently when they are repeatedly loaded above or below a tuneable threshold. Flexible hexagonal thin-wall structures were produced using three-dimensional printing, and their mechanical behaviour was assessed before and after repetitive loading at different magnitudes. These structures had an elastic mechanical behaviour until a critical pressure (P _crit = 252 kPa ± 17 kPa) beyond which they buckled. Assessing changes in stiffness after simulated use enabled the accurate detection of whether a sample was loaded above or below P _crit (sensitivity = 100%, specificity = 100%), with the overloaded samples becoming significantly softer. No specific P _crit value was targeted in this study. However, finite-element modelling showed that P _crit can be easily raised or lowered, through simple geometrical modifications, to become aligned with established thresholds for overloading (e.g. 200 kPa) or to assess overloading thresholds on a patient-specific basis. Although further research is needed, the results of this study indicate that clinically relevant overloading could indeed be reliably detected without the use of complex electronic in-shoe sensors.

Sensory-Motor Mechanisms Increasing Falls Risk in Diabetic Peripheral Neuropathy

Diabetic peripheral neuropathy (DPN) is associated with peripheral sensory and motor nerve damage that affects up to half of diabetes patients and is an independent risk factor for falls. Clinical implications of DPN-related falls include injury, psychological distress and physical activity curtailment. This review describes how the sensory and motor deficits associated with DPN underpin biomechanical alterations to the pattern of walking (gait), which contribute to balance impairments underpinning falls. Changes to gait with diabetes occur even before the onset of measurable DPN, but changes become much more marked with DPN. Gait impairments with diabetes and DPN include alterations to walking speed, step length, step width and joint ranges of motion. These alterations also impact the rotational forces around joints known as joint moments, which are reduced as part of a natural strategy to lower the muscular demands of gait to compensate for lower strength capacities due to diabetes and DPN. Muscle weakness and atrophy are most striking in patients with DPN, but also present in non-neuropathic diabetes patients, affecting not only distal muscles of the foot and ankle, but also proximal thigh muscles. Insensate feet with DPN cause a delayed neuromuscular response immediately following foot–ground contact during gait and this is a major factor contributing to increased falls risk. Pronounced balance impairments measured in the gait laboratory are only seen in DPN patients and not non-neuropathic diabetes patients. Self-perception of unsteadiness matches gait laboratory measures and can distinguish between patients with and without DPN. Diabetic foot ulcers and their associated risk factors including insensate feet with DPN and offloading devices further increase falls risk. Falls prevention strategies based on sensory and motor mechanisms should target those most at risk of falls with DPN, with further research needed to optimise interventions.

Modeling, Fabrication and Integration of Wearable Smart Sensors in a Monitoring Platform for Diabetic Patients

The monitoring of some parameters, such as pressure loads, temperature, and glucose level in sweat on the plantar surface, is one of the most promising approaches for evaluating the health state of the diabetic foot and for preventing the onset of inflammatory events later degenerating in ulcerative lesions. This work presents the results of sensors microfabrication, experimental characterization and FEA-based thermal analysis of a 3D foot-insole model, aimed to advance in the development of a fully custom smart multisensory hardware-software monitoring platform for the diabetic foot. In this system, the simultaneous detection of temperature-, pressure- and sweat-based glucose level by means of full custom microfabricated sensors distributed on eight reading points of a smart insole will be possible, and the unit for data acquisition and wireless transmission will be fully integrated into the platform. Finite element analysis simulations, based on an accurate bioheat transfer model of the metabolic response of the foot tissue, demonstrated that subcutaneous inflamed lesions located up to the muscle layer, and ischemic damage located not below the reticular/fat layer, can be successfully detected. The microfabrication processes and preliminary results of functional characterization of flexible piezoelectric pressure sensors and glucose sensors are presented. Full custom pressure sensors generate an electric charge in the range 0-20 pC, proportional to the applied load in the range 0-4 N, with a figure of merit of 4.7 ± 1 GPa. The disposable glucose sensors exhibit a 0-6 mM (0-108 mg/dL) glucose concentration optimized linear response (for sweat-sensing), with a LOD of 3.27 µM (0.058 mg/dL) and a sensitivity of 21 µA/mM cm2 in the PBS solution. The technical prerequisites and experimental sensing performances were assessed, as preliminary step before future integration into a second prototype, based on a full custom smart insole with enhanced sensing functionalities.

Monitoring of Dynamic Plantar Foot Temperatures in Diabetes with Personalised 3D-Printed Wearables

Diabetic foot ulcers (DFUs) are a life-changing complication of diabetes that can lead to amputation. There is increasing evidence that long-term management with wearables can reduce incidence and recurrence of this condition. Temperature asymmetry measurements can alert to DFU development, but measurements of dynamic information, such as rate of temperature change, are under investigated. We present a new wearable device for temperature monitoring at the foot that is personalised to account for anatomical variations at the foot. We validate this device on 13 participants with diabetes (no neuropathy) (group name D) and 12 control participants (group name C), during sitting and standing. We extract dynamic temperature parameters from four sites on each foot to compare the rate of temperature change. During sitting the time constant of temperature rise after shoe donning was significantly (p < 0.05) faster at the hallux (p = 0.032, 370.4 s (C), 279.1 s (D)) and 5th metatarsal head (p = 0.011, 481.9 s (C), 356.6 s (D)) in participants with diabetes compared to controls. No significant differences at the other sites or during standing were identified. These results suggest that temperature rise time is faster at parts of the foot in those who have developed diabetes. Elevated temperatures are known to be a risk factor of DFUs and measurement of time constants may provide information on their development. This work suggests that temperature rise time measured at the plantar surface may be an indicative biomarker for differences in soft tissue biomechanics and vascularisation during diabetes onset and progression.

Reprodutibilidade e concordância entre diferentes protocolos de baropodometria dinâmica durante a marcha: um estudo preliminar

RESUMO A identificação da pressão plantar durante a marcha é utilizada por clínicos e investigadores para verificar sobrecarga na estrutura podal. Neste particular, diferentes protocolos têm sido empregados para essa finalidade. O objetivo do estudo foi verificar a reprodutibilidade e a concordância de protocolos abreviados de marcha para identificar a pressão plantar dinâmica em jovens assintomáticos. Quinze voluntários foram submetidos aos protocolos abreviados one-step e three-step e ao protocolo padrão midgait em três momentos: inicial, dia seguinte e após sete dias. Para cada uma das oito máscaras podais, foram consideradas as medidas de pico de pressão plantar e integral pressão/tempo. A reprodutibilidade foi analisada mediante Anova one-way e coeficiente de correlação intraclasse, enquanto a concordância entre os protocolos foi verificada através de teste t pareado, correlação momento-produto de Pearson e plotagem de Bland-Altman. Os resultados apontaram que o protocolo three-step apresentou mais elevada reprodutibilidade em ambas as medidas de pressão plantar dinâmica. Quanto à concordância entre os protocolos, apesar de os abreviados demonstrarem tendência em subestimar as medidas produzidas pelo protocolo padrão midgait, na maioria das máscaras podais não foram identificadas diferenças estatísticas entre os escores médios. Ainda, por intermédio da técnica de Bland-Altman, constatou-se substancial capacidade de concordância entre as medidas identificadas pelos protocolos one-step, three-step e midgait. Concluindo, os protocolos abreviados devem ser selecionados de acordo com a medida de interesse da pressão plantar e a máscara podal a ser analisada, surgindo evidências de reprodutibilidade e concordância mais favoráveis para o uso do protocolo three-step.

The Role of Foot-Loading Factors and Their Associations with Ulcer Development and Ulcer Healing in People with Diabetes: A Systematic Review

We aimed to comprehensively and systematically review studies associating key foot-loading factors (i.e., plantar pressure, weight-bearing activity, adherence or a combination thereof) with ulcer development and ulcer healing in people with diabetes. A systematic literature search was performed in PubMed and EMBASE. We included studies if barefoot or in-shoe plantar pressure, weight-bearing activity or footwear or device adherence was measured and associated with either ulcer development or ulcer healing in people with diabetes. Out of 1954 records, 36 studies were included and qualitatively analyzed. We found low to moderate quality evidence that lower barefoot plantar pressure and higher footwear and device adherence associate with lower risk of ulcer development and shorter healing times. For the other foot-loading factors, we found low quality evidence with limited or contradictory results. For combined measures of foot-loading factors, we found low quality evidence suggesting that lower cumulative plantar tissue stress is associated with lower risk of ulcer development and higher ulcer healing incidence. We conclude that evidence for barefoot plantar pressure and adherence in association with ulcer outcome is present, but is limited for the other foot-loading factors. More comprehensive investigation in particularly the combination of foot-loading factors may improve the evidence and targeting preventative treatment.

The role of foot pressure measurement in the prediction and prevention of diabetic foot ulceration-A comprehensive review

The predominant risk factor of diabetic foot ulcers (DFU), peripheral neuropathy, results in loss of protective sensation and is associated with abnormally high plantar pressures. DFU prevention strategies strive to reduce these high plantar pressures. Nevertheless, several constraints should be acknowledged regarding the research supporting the link between plantar pressure and DFUs, which may explain the low prediction ability reported in prospective studies. The majority of studies assess vertical, rather than shear, barefoot plantar pressure in laboratory-based environments, rather than during daily activity. Few studies investigated previous DFU location-specific pressure. Previous studies focus predominantly on walking, although studies monitoring activity suggest that more time is spent on other weight-bearing activities, where a lower "peak" plantar pressure might be applied over a longer duration. Although further research is needed, this may indicate that an expression of cumulative pressure applied over time could be a more relevant parameter than peak pressure. Studies indicated that providing pressure feedback might reduce plantar pressures, with an emerging potential use of smart technology, however, further research is required. Further pressure analyses, across all weight-bearing activities, referring to location-specific pressures are required to improve our understanding of pressures resulting in DFUs and improve effectiveness of interventions.

(Cost-)effectiveness of lower extremity nerve decompression surgery in subjects with diabetes: the DeCompression (DECO) trial-study protocol for a randomised controlled trial

INTRODUCTION

The peripheral nerves of patients with diabetes are often pathologically swollen, which results in entrapment at places of anatomical narrowing. This results in nerve dysfunction. Surgical treatment of compression neuropathies in the lower extremities (lower extremity nerve decompression (LEND)) results in relief of symptoms and gain in peripheral nerve function, which may lead to less sensory loss (short term) and less associated detrimental effects including foot ulceration and amputations, and lower costs (long term). The aim of the DeCompression trial is to evaluate the effectiveness and (cost-)effectiveness of surgical decompression of compressed lower extremity nerves (LEND surgery) compared with patients treated with conventional (non-surgical) care.

METHODS AND ANALYSIS

A stratified randomised (1 to 1) controlled trial comparing LEND surgery (intervention) with conventional non-surgical care (control strategy) in subjects with diabetes with problems of neuropathy due to compression neuropathies in the lower extremity. Randomisation is stratified for participating hospital (n=11) and gender. Patients and controls have the same follow-up at 1.5, 3, 6, 9, 12, 18, 24 and 48 months. Participants (n=344) will be recruited in 12 months and enrolled in all affiliated hospitals in which they receive both the intervention or conventional non-surgical care and follow-up. Outcome assessors are blinded to group assignment.

PRIMARY OUTCOME

disease-specific quality of life (Norfolk Quality of Life Questionnaire-Diabetic Neuropathy).

SECONDARY OUTCOMES

health-related quality of life (EuroQoL 5-dimension 5-level (EQ-5D5L), 36-item Short Form (SF-36)), plantar sensation (Rotterdam Diabetic Foot Test Battery), incidence of ulcerations/amputations, resource use and productivity loss (Medical Cost Questionnaire, Productivity Cost Questionnaire) during follow-up. The incremental cost-effectiveness ratio will be estimated on the basis of the collected empirical data and a cost-utility model.

ETHICS AND DISSEMINATION

Ethics approval has been granted by the Medical Research Ethics Committee of Utrecht University Medical Center (reference: NL68312.041.19v5, protocol number: 19-335/M). Dissemination of results will be via journal articles and presentations at national and international conferences.

TRIAL REGISTRATION NUMBER

NetherlandsTrial Registry NL7664.