Gait parameters of people with diabetes-related neuropathic plantar foot ulcers

Effects of Wound Localisation on Balance, Performance, Muscle Strength, and Gait Speed in Individuals with Diabetic Foot Ulcer: A Cross-Sectional Study

Muscle strength, balance, performance, and gait speed of individuals diagnosed with diabetic foot wound are negatively affected. This study aimed to investigate the effects of wound localisation on balance, performance, muscle strength, and gait speed in individuals with diabetic foot wounds. Individuals (n = 48) with a mean age of 59.35 ± 11.28 years and were divided into two groups according to wound localisation as group 1 (n = 24) with forefoot wounds and group 2 (n = 24) with hindfoot wounds. Four Step Square Test was used for dynamic balance assessment, Timed Up and Go Test for performance, Manual Muscle Tests for muscle strength, and 10 Meter Walk Test for gait speed assessment. When compared in terms of muscle strength, there was a difference only between the injured side Gluteus Medius (p = 0.02), Gastrosoleus (p = 0.00), and Tibialis Anterior (p = 0.03) muscles. Other muscle groups strength, balance, performance, and gait speed were similar (p > 0.05). Loss of muscle strength can lead to serious negative consequences such as deformity and new wound formation if not intervened in time. The effects on balance and performance are similar in different wound localizations.

Lower limb gait joint coordination variability in people with diabetes-related foot ulcers

BACKGROUND

Diabetes-related foot ulcers pose substantial health risks globally, yet the biomechanical intricacies underlying their development remain incompletely understood. This study aimed to evaluate lower limb gait joint coordination variability in individuals with diabetes-related foot ulcers compared to those with diabetes (without diabetes-related foot ulcers) and healthy controls.

METHODS

A total of 99 participants (diabetes-related foot ulcers cases - 16, Diabetes controls - 50, Health controls - 33) compared three self-paced walking trials. Vector coding, a technique quantifying movement coordination, was employed, analysing hip-knee, knee-ankle, and hip-angle joint couplings in the sagittal plane.

FINDINGS

No significant differences in coordination variability were found among the groups. However, distinct coupling pattern frequencies emerged, with diabetes-related foot ulcers cases exhibiting unique anti-phase hip and ankle coupling frequency counts compared to healthy controls.

INTERPRETATION

These findings challenge conventional understandings of diabetes-related foot ulcers biomechanics and underscore the complexity of gait in this population.

An overview of current developments and methods for identifying diabetic foot ulcers: A survey

Diabetic foot ulcers (DFUs) present a substantial health risk across diverse age groups, creating challenges for healthcare professionals in the accurate classification and grading. DFU plays a crucial role in automated health monitoring and diagnosis systems, where the integration of medical imaging, computer vision, statistical analysis, and gait information is essential for comprehensive understanding and effective management. Diagnosing DFU is imperative, as it plays a major role in the processes of diagnosis, treatment planning, and neuropathy research within automated health monitoring and diagnosis systems. To address this, various machine learning and deep learning‐based methodologies have emerged in the literature to support healthcare practitioners in achieving improved diagnostic analyses for DFU. This survey paper investigates various diagnostic methodologies for DFU, spanning traditional statistical approaches to cutting‐edge deep learning techniques. It systematically reviews key stages involved in diabetic foot ulcer classification (DFUC) methods, including preprocessing, feature extraction, and classification, explaining their benefits and drawbacks. The investigation extends to exploring state‐of‐the‐art convolutional neural network models tailored for DFUC, involving extensive experiments with data augmentation and transfer learning methods. The overview also outlines datasets commonly employed for evaluating DFUC methodologies. Recognizing that neuropathy and reduced blood flow in the lower limbs might be caused by atherosclerotic blood vessels, this paper provides recommendations to researchers and practitioners involved in routine medical therapy to prevent substantial complications. Apart from reviewing prior literature, this survey aims to influence the future of DFU diagnostics by outlining prospective research directions, particularly in the domains of personalized and intelligent healthcare. Finally, this overview is to contribute to the continual evolution of DFU diagnosis in order to provide more effective and customized medical care.

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Analysis of the interplay between proximal lower limb and foot joint structures as a mechanical predictor of neuropathic ulceration

BACKGROUND

Diabetes-related foot ulcers are a leading cause of morbidity and mortality globally, in which the most significant contributing factor is peripheral neuropathy. The purpose of this research was to evaluate the influence of diabetic peripheral neuropathy and ulceration on lower limb and foot joint kinematics during gait.

RESEARCH QUESTION

Are there any significant alterations lower limb and foot joint kinematics during gait in the presence of active and history of diabetic neuropathic ulceration?

METHODS

A prospective, cross-sectional study was conducted, recruiting eighty adult participants who were equally divided into four groups, namely, the diabetes (DM), diabetic peripheral neuropathy (DPN), active diabetic neuropathic ulceration (DNU) and history of diabetic neuropathic ulceration (DHNU) groups. Three-dimensional gait analysis was performed, and participants were instructed to walk barefoot over a 10-m walkway at self-selected speed. The acquired pelvic, hip, knee, ankle and foot joint segmental kinematic data was compared between individuals with and without active neuropathic ulceration.

RESULTS

Mean scores between the four independent groups was performed using the Kruskal-Wallis test. Participants within the DNU and DHNU groups demonstrated significantly reduced knee flexion, ankle dorsiflexion and first metatarsal dorsiflexion kinematics with resultant increased anterior pelvic tilt, hip flexion and midtarsal kinematics (all values p<0.01) when compared to participants within the DM and DPN groups.

SIGNIFICANCE

Through the integration of a more individualised, biomechanical approach, the findings in this study may provide improved preventative and management strategies of ulceration amongst the diabetic population.

An exploratory in-situ dynamic mechanical analysis on the shearing stress-strain mechanism of human plantar soft tissue

A DMA (dynamic mechanical analysis)-like device based on the principle of classical viscoelasticity testing is invented to investigate the in-situ/in-vivo shear-bearing mechanism of plantar soft tissue. Forty-three volunteers were recruited for the shear-strain test in the longitudinal and transverse directions at five anatomical spots on the plantar surface. Several encouraging observations indicated significant variances among different spots and individuals, implying that the outer forefoot surrounding the second, fifth metatarsal head is a more intensive shear-bearing region on the plantar surface compared to the inner forefoot under the first metatarsal head, and drawing the hypothesis of a significant effect of BMI on the shear-bearing property. The speculations agree with our expectations and other previous research. The feasibility and practical value of this novel approach are substantiated, and these intriguing discoveries provide foundational underpinnings for further in-depth investigations.

Potential predictive effect of mechanical properties of the plantar skin and superficial soft tissue, and vibration perception on plantar loading during gait in individuals with diabetes

BACKGROUND

This exploratory study aimed to investigate the extent to which mechanical properties of the plantar skin and superficial soft tissue (hardness, stiffness, and thickness) and vibration perception thresholds (VPTs) predict plantar pressure loading during gait in people with diabetes compared to healthy controls.

METHODS

Mechanical properties, VPTs, and plantar loadings during gait at the heel and first metatarsal head (MTH) of 20 subjects with diabetes, 13 with DPN, and 33 healthy controls were acquired. Multiple regression analyses were used to predict plantar pressure peaks and pressure-time integrals at both locations based on the mechanical properties of the skin and superficial soft tissues and VPTs.

RESULTS

In the diabetes group at the MTH, skin hardness associated with 30-Hz (R2 = 0.343) and 200-Hz (R2 = 0.314) VPTs predicted peak pressure at the forefoot. In the controls at the heel, peak pressure was predicted by the skin thickness, hardness, and stiffness associated with 30-Hz (R2 = 0.269, 0.268, and 0.267, respectively) and 200-Hz (R2 = 0.214, 0.247, and 0.265, respectively) VPTs.

CONCLUSION

The forefoot loading of people with diabetes can be predicted by the hardness of the skin when combined with loss of vibration perception at low (30-Hz) and high (200-Hz) frequencies. Further data from larger sample sizes are needed to confirm the current findings.

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.

Effects of foot-ankle exercises on foot-ankle kinematics, plantar pressure, and gait kinetics in people with diabetic neuropathy: Secondary outcomes from a randomized controlled trial

BACKGROUND

Follow-up report of secondary outcomes of a randomized, single-blinded, parallel controlled trial that investigated the benefits of a foot-ankle therapeutic exercise program on foot-ankle kinematics, plantar pressure, and lower limb kinetics during gait in individuals with diabetic neuropathy (DPN).

METHODS

Sixty-six participants with DPN were randomly allocated into a control group (CG; n = 31), which received usual care, and an intervention group (IG; n = 35), which received usual care plus a 12-week group-based foot-ankle exercise program. Outcomes were assessed at baseline and 12 weeks by an assessor blinded to group allocation.

RESULTS

The generalized linear mixed model and intention-to-treat analysis revealed a greater hip extensor moment at push-off and greater hallux contact area in the IG than CG after 12 weeks. A within-group analysis revealed a larger arch height during stance and higher peak pressure and pressure-time integral at the central forefoot region in the IG after 12 weeks compared to baseline. There were no other significant group difference or changes over time in foot-ankle kinematics or in any other joint moment related to overall lower limb biomechanics.

CONCLUSION

The increases in hip moment at push-off and hallux surface contact area suggest an improvement in the propulsion phase with greater participation of the toes in foot rollover after 12 weeks of a group-based foot-ankle exercises program for people with DPN. Individual face-to-face, longer-term, and more intensive interventions may be needed to positively influence foot-ankle biomechanics and pressure parameters in other plantar areas.

A portable non-invasive microwave based head imaging system using compact metamaterial loaded 3D unidirectional antenna for stroke detection

A metamaterial (MTM) loaded compact three-dimensional antenna is presented for the portable, low-cost, non-invasive microwave head imaging system. The antenna has two slotted dipole elements with finite arrays of MTM unit cell and a folded parasitic patch that attains directional radiation patterns with 80% of fractional bandwidth. The operating frequency of the antenna is 1.95–4.5 GHz. The optimization of MTM unit cell is performed to increase the operational bandwidth, realized gain, and efficiency of the antenna within the frequency regime. It is also explored to improve radiation efficiency and gain when placed to head proximity. One-dimensional mathematical modelling is analyzed to precisely estimate the power distribution that validates the performance of the proposed antenna. To verify the imaging capability of the proposed system, an array of 9 antennas and a realistic three-dimensional tissue-emulating experimental semi-solid head phantom are fabricated and measured. The backscattered signal is collected from different antenna positions and processed by the updated Iterative Correction of Coherence Factor Delay-Multiply-and-Sum beamforming algorithm to reconstruct the hemorrhage images. The reconstructed images in simulation and experimental environment demonstrate the feasibility of the proposed system as a portable platform to successfully detect and locate the hemorrhages inside the brain.

Machine Learning-Based Diabetic Neuropathy and Previous Foot Ulceration Patients Detection Using Electromyography and Ground Reaction Forces during Gait

Diabetic neuropathy (DN) is one of the prevalent forms of neuropathy that involves alterations in biomechanical changes in the human gait. Diabetic foot ulceration (DFU) is one of the pervasive types of complications that arise due to DN. In the literature, for the last 50 years, researchers have been trying to observe the biomechanical changes due to DN and DFU by studying muscle electromyography (EMG) and ground reaction forces (GRF). However, the literature is contradictory. In such a scenario, we propose using Machine learning techniques to identify DN and DFU patients by using EMG and GRF data. We collected a dataset from the literature which involves three patient groups: Control (n = 6), DN (n = 6), and previous history of DFU (n = 9) and collected three lower limb muscles EMG (tibialis anterior (TA), vastus lateralis (VL), gastrocnemius lateralis (GL)), and three GRF components (GRFx, GRFy, and GRFz). Raw EMG and GRF signals were preprocessed, and different feature extraction techniques were applied to extract the best features from the signals. The extracted feature list was ranked using four different feature ranking techniques, and highly correlated features were removed. In this study, we considered different combinations of muscles and GRF components to find the best performing feature list for the identification of DN and DFU. We trained eight different conventional ML models: Discriminant analysis classifier (DAC), Ensemble classification model (ECM), Kernel classification model (KCM), k-nearest neighbor model (KNN), Linear classification model (LCM), Naive Bayes classifier (NBC), Support vector machine classifier (SVM), and Binary decision classification tree (BDC), to find the best-performing algorithm and optimized that model. We trained the optimized the ML algorithm for different combinations of muscles and GRF component features, and the performance matrix was evaluated. Our study found the KNN algorithm performed well in identifying DN and DFU, and we optimized it before training. We found the best accuracy of 96.18% for EMG analysis using the top 22 features from the chi-square feature ranking technique for features from GL and VL muscles combined. In the GRF analysis, the model showed 98.68% accuracy using the top 7 features from the Feature selection using neighborhood component analysis for the feature combinations from the GRFx-GRFz signal. In conclusion, our study has shown a potential solution for ML application in DN and DFU patient identification using EMG and GRF parameters. With careful signal preprocessing with strategic feature extraction from the biomechanical parameters, optimization of the ML model can provide a potential solution in the diagnosis and stratification of DN and DFU patients from the EMG and GRF signals.

Plantar shear stress in the diabetic foot: A systematic review and meta-analysis

AIMS

Diabetic foot ulceration (DFU) is a multifactorial process involving undetected, repetitive trauma resulting in inflammation and tissue breakdown. Shear stress forms a major part of plantar load, the aim of this review is to determine whether elevated shear stress results in ulceration.

METHODS

A systematic review of the Ovid Medline, EMBASE, CINAHL and Cochrane library databases was performed. Studies involving patients with diabetes who underwent plantar shear stress assessment were included. The primary outcome was plantar shear stress in patients with diabetes who had a current/previous DFU compared with those with no prior ulceration. Meta-analysis was performed comparing shear stress between those with a current or previous DFU and those without, and those with diabetes and healthy controls.

RESULTS

The search strategy identified 1461 potentially relevant articles, 16 studies met the inclusion criteria, involving a total of 597 patients. Comparing shear stress between the current/previous DFU group and those without: Standardised mean difference (SMD) 0.62 (95% CI -0.01 to 1.25), in favour of greater shear stress within the DFU group, p = 0.05. Comparing shear stress between people with diabetes and healthy controls: 0.36 (95% CI -0.31 to 1.03), in favour of greater shear stress within the diabetes group, p = 0.29.

CONCLUSION

This review suggests that that patients with diabetes and a history of ulceration exhibit greater shear stress than their ulcer-free counterparts. This strengthens the premise that development of systems to measure shear stress may be helpful in DFU prediction and prevention.

Wearable Sensor for Assessing Gait and Postural Alterations in Patients with Diabetes: A Scoping Review

Background and Objectives: Diabetes mellitus is considered a serious public health problem due to its high prevalence and related complications, including gait and posture impairments due to neuropathy and vascular alterations and the subsequent increased risk of falls. The gait of patients with diabetes is characterized by alterations of the main spatiotemporal gait parameters such as gait velocity, cadence, stride time and length, which are also known to worsen with disease course. Wearable sensor systems can be used for gait analysis by providing spatiotemporal parameters and postural control (evaluated from the perspective of body sway), useful for investigating the disease progression. Thanks to their small size and low cost of their components, inertial measurement units (IMUs) are easy to wear and are cheap tools for movement analysis. Materials and Methods: The aim of this study is to review articles published in the last 21 years (from 2000 to 2021) concerning the application of wearable sensors to assess spatiotemporal parameters of gait and body postural alterations in patients with diabetes mellitus. Relevant articles were searched in the Medline database using PubMed, Ovid and Cochrane libraries. Results: One hundred and four articles were initially identified while searching the scientific literature on this topic. Thirteen were selected and analysed in this review. Wearable motion sensors are useful, noninvasive, low-cost, and objective tools for performing gait and posture analysis in diabetic patients. The IMUs can be worn at the lumber levels, tibias or feet, and different spatiotemporal parameters of movement and static posture can be assessed. Conclusions: Future research should focus on standardizing the measurement setup and selecting the most informative spatiotemporal parameters for gait and posture analysis.

The effect of induced joint restriction on plantar pressure during gait - a pilot study

BACKGROUND

The aim of this study was to analyse the effect of induced lower limb joint restriction on plantar pressures during gait. Focusing on restricting a single joint, without the effect of other co-morbidities, would provide better understanding as to the resultant plantar loadings during gait, which would be especially beneficial in patients requiring offloading procedures.

RESEARCH QUESTION

Does induced lower limb joint restriction affect plantar pressure distribution during gait?

METHODS

A prospective, quasi-experimental study was conducted, recruiting ten healthy, adult participants who were instructed to walk barefoot over a Tekscan HR Mat™. This procedure was repeated after separately inducing restriction of the hip, knee and ankle joints. Mean peak plantar pressure (MPP) and pressure-time integral (PTI) data were analysed to compare between unrestricted and restricted data.

RESULTS

Significant plantar pressure changes were observed in the heel and first metatarsal regions. Rearfoot PTIs were increased with restriction of the contralateral hip (left p <0.001) (right p =0.02) and knee joints (left p =0.01) (right p =0.04). Both MPPs (left p =0.01; right p =0.01) and PTIs (left p =0.004; right p =0.03) were increased in the first metatarsal when restricting the hip joint of the same limb. MPP was decreased in the left first metatarsal with induced knee (left p =0.01; right p =0.04) and ankle (left and right p <0.001) joint restriction. Finally, MPP was decreased in the right first metatarsal with knee (left and right p =0.01) and ankle (left p =0.04; right p =0.01) joint restriction.

SIGNIFICANCE

Limited joint mobility may have a direct effect on plantar pressure, particularly with restriction in the hip and knee joints, hence careful attention should be given especially in patients with conditions involving plantar loadings. Results in this study also show that PTI changes during gait should be equally evaluated clinically along with peak plantar pressure analysis.

Does a weight bearing equinus affect plantar pressure differently in older people with and without diabetes? A case control study

BACKGROUND

A weight bearing ankle equinus has adverse effects on forefoot plantar pressure variables in older adults with diabetes, but it is unclear if this is also the case in older adults without diabetes.

METHODS

40 older adults with diabetes (88% type 2, mean diabetes duration 17.6 ± 14.8 years) and 40 older adults without diabetes, matched for age (±3 years), sex and BMI (±2 BMI units) were included (63% female, mean age 72 ± 4 years, BMI 30 ± 4 kg/m²). Primary outcomes were prevalence of a weight bearing equinus and evaluation of barefoot forefoot plantar pressures in older adults with and without diabetes.

FINDINGS

A weight bearing equinus was present in 37.5% and 27.5% of the diabetes and non-diabetes group respectively with no significant difference between groups (p = 0.470). People with diabetes and equinus displayed higher peak pressure (808 versus 540 kPa, p = 0.065) and significantly higher pressure-time integral (86 versus 68 kPa/s, p = 0.030) than people with diabetes and no equinus group. The non-diabetes equinus group had significantly higher peak pressure (665 versus 567 kPa, p = 0.035) than those with no diabetes and no equinus, but no difference in pressure-time integral.

INTERPRETATION

A high prevalence of a weight bearing equinus was detected in older adults with and without diabetes, with associated increases in plantar pressures. As an equinus has been associated with many foot pathologies this study's findings suggest that clinicians should check for the presence of a weight bearing ankle equinus in all older adults.

The Feasibility and Effectiveness of Wearable Sensor Technology in the Management of Elderly Diabetics with Foot Ulcer Remission: A Proof-Of-Concept Pilot Study with Six Cases

AIMS

Using specials wearable sensors, we explored changes in gait and balance parameters, over time, in elderly patients at high risk of diabetic foot, wearing different types of footwear. This assessed the relationship between gait and balance changes in elderly diabetic patients and the development of foot ulcers, in a bid to uncover potential benefits of wearable devices in the prognosis and management of the aforementioned complication.

METHODS

A wearable sensor-based monitoring system was used in middle-elderly patients with diabetes who recently recovered from neuropathic plantar foot ulcers. A total of 6 patients (age range: 55-80 years) were divided into 2 groups: the therapeutic footwear group (n = 3) and the regular footwear (n = 3) group. All subjects were assessed for gait and balance throughout the study period. Walking ability and gait pattern were assessed by allowing participants to walk normally for 1 min at habitual speed. The balance assessment program incorporated the "feet together" standing test and the instrumented modified Clinical Test of Sensory Integration and Balance. Biomechanical information was monitored at least 3 times.

RESULTS

We found significant differences in stride length (p < 0.0001), stride velocity (p < 0.0001), and double support (p < 0.0001) between the offloading footwear group (OG) and the regular footwear group on a group × time interaction. The balance test embracing eyes-open condition revealed a significant difference in Hip Sway (p = 0.004), COM Range ML (p = 0.008), and COM Position (p = 0.004) between the 2 groups. Longitudinally, the offloading group exhibited slight improvement in the performance of gait parameters over time. The stride length (odds ratio 3.54, 95% CI 1.34-9.34, p = 0.018) and velocity (odds ratio 3.13, 95% CI 1.19-8.19, p = 0.033) of OG patients increased, converse to the double-support period (odds ratio 6.20, 95% CI 1.97-19.55, p = 0.002), which decreased.

CONCLUSIONS

Special wearable devices can accurately monitor gait and balance parameters in patients in real time. The finding reveals the feasibility and effectiveness of advanced wearable sensors in the prevention and management of diabetic foot ulcer and provides a solid background for future research. In addition, the development of foot ulcers in elderly diabetic patients may be associated with changes in gait parameters and the nature of footwear. Even so, larger follow-up studies are needed to validate our findings.

Management of diabetic foot ulcers: a 25% lidocaine topical cream formulation design, physicochemical and microbiological assessments

Background

Given the importance of surgical debridement in healing of diabetic foot ulcers, effective local anaesthesia is required to manage the related extreme pain. The pharmaceutical proprietary products currently available have low concentrations and do not exceed 5% w/w local anaesthetic.

Objective

Formulation design of a lidocaine cream of 25% and assessment of the intrinsic stability.

Methods

A cream pharmaceutical form was chosen for its ability to cross the skin barrier and effectively anaesthetise the skin. The choice of cream formula is based on changes in the size of the emulsions and resistance to physical stress. Stability tests were assessed over a 6-month period in terms of physical (evaluation of oil droplets), microbiological (germ count and identification, and preservative antimicrobial efficacy) and chemical parameters (content and pH).

Results

Under the study conditions, the drug product displayed good physicochemical and microbiological stability for 6 months at 20°C and 40°C, and no degradation product was detected. Due to the systemic adverse effects of lidocaine, the pH stability guarantee the drug product tolerance along with very weak systemic passage.

Conclusions

Given the good physicochemical and microbiological stability of the drug product over 6-month period, it has been made available to the clinical unit. An average of 250 patients per year benefit from the treatment with an excellent efficacy/tolerability ratio.

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.

The impact of diabetic foot ulcers and unilateral offloading footwear on gait in people with diabetes

BACKGROUND

Unilateral offloading footwear prescribed to patients with diabetic foot ulcers elevates one limb relative to the other, which may lead to limp and abnormal gait. This study investigated whether the unilateral foot ulcer and offloading combination negatively impacts gait function beyond diabetic peripheral neuropathy.

METHODS

Eighty-six participants were recruited in 3 groups: 12 with diabetic peripheral neuropathy and unilateral foot ulcers wearing offloading footwear (offloading group, age = 55.6 ± 9.5 years, BMI = 30.9 ± 4.5 kg/m2), 27 with diabetic peripheral neuropathy (neuropathy group, age = 64.3 ± 7.7 years, BMI = 30.9 ± 5.4 kg/m2), and 47 non-diabetic controls (non-diabetic group, age = 62.9 ± 16.1 years, BMI = 29.0 ± 6.0 kg/m2). Gait function was quantified during a habitual speed walking test using a validated wearable platform.

FINDINGS

The offloading group exhibited deteriorated gait function compared to the non-diabetic group (p < 0.005, Cohen's effect size d = 0.90-2.61). They also had decreased gait speed (p < 0.001, d = 1.79) and stride length (p < 0.001, d = 1.76), as well as increased gait cycle time (p < 0.001, d = 1.67) and limp (p < 0.050, d = 0.72-1.49) compared to the neuropathy group. The offloading group showed increased gait unsteadiness compared to the neuropathy group, but the difference did not reach statistical significance in our samples.

INTERPRETATION

This study demonstrated that while diabetic peripheral neuropathy deteriorates gait function, including increasing gait unsteadiness and limp, the diabetic foot ulcer and offloading combination magnifies the deterioration beyond diabetic peripheral neuropathy. These findings promote caution of the current standards of care for treating diabetic foot ulcers with offloading footwear. However, it is possible that a contralateral shoe lift may remedy deteriorated gait function and improve quality of life for unilateral offloading users.

Evaluation of spatio-temporal gait parameters and gait symmetry in diabetic polyneuropathic patients with burn injury: A pilot study

PURPOSE

The purpose of this study was to investigate the effects of burn injury on spatio-temporal gait parameters and gait symmetry in individuals with diabetic polyneuropathy (DPN)-related lower extremity burn injury.

METHODS

Demographic information and the physical examinations of the lower extremities of 14 patients with unilateral lower extremity burn injury due to DPN (DPN_B) and 14 uninjured patients with DPN (DPN₀) were recorded. The GAITRite computerized gait analysis system was used to evaluate the spatio-temporal parameters of gait. Symmetry Index (SI) was calculated to determine gait symmetry. The Mann Whitney U test was used to determine the demographical and clinical differences between the groups, the Wilcoxon's test was used to compare both sides of all the participants for all gait parameters and linear regression analysis was used to find the variables that affect gait parameters.

RESULTS

The groups were similar in terms of their demographic information except for age. Compared with the DPN₀ group, DPN_B group had increased extent of area with sensory loss and severity of DPN, decreased ankle joint range of motions and intrinsic foot muscles strength and they displayed lower gait speed, step length, stride length and swing percentage but their double support and stance percentage were increased.

CONCLUSION

This study results have shown that, spatio-temporal gait parameters of DPN_B patients are different. These differences in spatiotemporal parameters are found on both sides, probably owing to the symmetric and bilateral sensory loss is superior to unilateral burn injury due to symmetrical and bilateral sensory loss. Gait analysis should be considered in order to reveal the changes in gait parameters and to improve appropriate healing process of patients with DPN-related lower extremity burn injury.

Gait in People With Nonhealing Diabetes-Related Plantar Ulcers

BACKGROUND

Abnormalities in gait have been associated with high plantar pressures and diabetes-related plantar foot ulcers. Whether these are a transient response to the ulcer or are representative of long-term lower limb biomechanical abnormalities is currently unknown.

OBJECTIVE

The aim of this study was to examine whether 12 gait parameters identified as being associated with nonhealing diabetes-related plantar foot ulcers at baseline remained associated during a 6-month follow-up period.

DESIGN

This was a longitudinal observational case-control study.

METHODS

Gait assessments were performed at entry and twice during follow-up over a 6-month period in 12 participants with nonhealing diabetes-related plantar foot ulcers (case participants) and 62 people with diabetes and no history of foot ulcers (control participants) using a standardized protocol. Linear mixed-effects random-intercept models were used to identify gait parameters that consistently differed between case participants and control participants at all assessments after adjustment for age, sex, body mass index, presence of peripheral neuropathy, and follow-up time. Standardized mean differences (SMD) were used to measure effect sizes.

RESULTS

Five of the 12 gait parameters were significantly different between case participants and control participants at all 3 time points. Case participants had a more abducted foot progression angle (SMD = 0.37), a higher pelvic obliquity at toe-off (SMD = -0.46), a greater minimum pelvic obliquity (SMD = -0.52), a lower walking speed (SMD = -0.46), and a smaller step length (SMD = -0.46) than control participants.

LIMITATIONS

The limitations included a small sample size, the observational nature of the study, and the inability to evaluate the impact of gait on wound healing.

CONCLUSIONS

This study identified abnormal gait parameters consistently associated with nonhealing diabetes-related plantar foot ulcers. Further research is needed to test the clinical importance of these gait characteristics.

Measuring Plantar Tissue Stress in People With Diabetic Peripheral Neuropathy: A Critical Concept in Diabetic Foot Management

Excessive stress on plantar tissue over time is one of the leading causes of diabetic foot ulcers among people with diabetic peripheral neuropathy. Plantar tissue stress (PTS) is a concept that attempts to integrate several well-known mechanical factors into one measure, including plantar pressure, shear stress, daily weight-bearing activity, and time spent in prescribed offloading interventions (adherence). Despite international diabetic foot guidelines recommending the measure of each of these individual mechanical factors in people with neuropathy, only recently has technology enabled their combined measurement to determine PTS. In this article we review the concept of PTS, the mechanical factors involved, and the findings of pivotal articles reporting measures of PTS in people with neuropathy. We also discuss key existing gaps in this field, including the lack of standards to measure and report PTS, a lack of practical solutions to measure shear stress, and the lack of PTS thresholds that may indicate benefit or detriment to people with neuropathy. To address some of these gaps, we propose recommended clinical and research standards for measuring and reporting PTS in people with neuropathy. Last, we forecast future clinical, research, and technological advancements that may use PTS to highlight the importance of this critical concept in the prevention and management of diabetic foot ulcers.

Within- and Between-Body-Site Agreement of Skin Autofluorescence Measurements in People With and Without Diabetes-Related Foot Disease

BACKGROUND

Skin autofluorescence has been used to assess longer term glycemic control and risk of complications. There is however no agreed site at which autofluorescence should be measured. This study evaluated the within- and between-site agreement in measurement of skin autofluorescence using a noninvasive advanced glycation end product (AGE) reader.

METHODS

Overall, 132 participants were included: 16 with diabetes-related foot ulcers (DFU), 63 with diabetes but without foot ulcers (DMC), 53 without diabetes or foot ulcers (HC). Skin autofluorescence was measured using the AGE Reader (DiagnOptics technologies BV, the Netherlands). Three consecutive skin autofluorescence measurements were each performed at six different body sites: the volar surfaces of both forearms (arms), dorsal surfaces of both calves (legs), and plantar surfaces of both feet (feet). Within- and between-site agreements were analyzed with concordance correlation coefficients (CCC) and 95% confidence intervals (95% CI), absolute mean differences (±standard deviation), and Bland-Altman limits of agreement.

RESULTS

The agreement between repeat assessments at the same site was almost perfect (CCC [95% CI] ranging from 0.94 [0.91-0.96] for assessments in the right foot to 0.99 [0.99-0.99] for assessments in the left arm). The limits of agreement were narrow within ±0.5 arbitrary units for all sites. The between-site agreement in measurements was poor (CCC < 0.65) with large maximum absolute mean differences (±SD) in arbitrary units (DFU = 3.40 [±2.04]; DMC = 3.15 [±2.45]; HC = 2.72 [±1.83]) and wide limits of agreement.

CONCLUSIONS

Skin autofluorescence measurements can be repeated at the same site with adequate repeatability but measurements at different sites in the same patient have marked differences. The reason for this variation across sites and whether this has any role in diabetes-related complications needs further investigation.

Reliability of peak foot pressure in patients with previous diabetic foot ulceration

BACKGROUND

Previous reliability studies on peak plantar pressure measurements in patients with previous diabetic foot ulceration (DFU) did not stratify their analyses according to whether the foot had a previous ulcer.

RESEARCH QUESTION

Does test-retest reliability of peak foot pressure measurements from the various foot regions differ between the ulcerated and non-ulcerated feet?

METHODS

Data from 23 participants with peripheral neuropathy and healed plantar DFU were analysed in this test-retest reliability comparison study. Plantar pressure was evaluated on two sessions using Pedar^®-X in-shoe system, with a mean of 7.2 days (SD = 1.6) between sessions.

RESULTS

The intraclass correlation coefficient (ICC) and coefficient of variation (CV) were calculated for 10 foot regions. Overall, test-retest reliability was excellent (ICCs, 0.82 to 0.95) for all peak pressure variables. CV ranged between 6.3% and 18.3%, and exceeded 15% over the hallux and medial forefoot regions in the ulcer foot (18.3% and 16.4%, respectively). Hallux peak pressure CV was significantly higher over the ulcer foot than over the non-ulcer foot (5.7%, 95% CI, 1.7%-10.2%). Peak pressure CV over the forefoot also tended to be higher over the ulcer foot (medial forefoot: 6.1%, 95% CI, -0.5%-14.5%; lateral forefoot: 4.1%, 95%CI, -0.7%-11.1%).

SIGNIFICANCE

Peak plantar foot pressure may be useful to distinguish between groups of patients with peripheral neuropathy and healed plantar DFU. However, clinical decisions based on ulcer foot hallux and forefoot peak pressure measurements should be interpreted with caution.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Factors associated with wearing inadequate outdoor footwear in populations at risk of foot ulceration: A cross-sectional study

BACKGROUND

Few studies have investigated if people at risk of foot ulceration actually wear the footwear recommended by best practice guidelines to prevent foot ulceration. This study aimed to investigate the prevalence of, and factors associated with, wearing inadequate outdoor footwear in those with diabetes or peripheral neuropathy in an inpatient population.

METHODS

This was a secondary analysis of a multi-site cross-sectional study investigating foot conditions in a large representative inpatient population admitted into hospital for any medical reason on one day. A range of explanatory variables were collected from all participants including sociodemographic, medical and foot condition factors. The outcome variable for this study was the self-reported outdoor footwear type worn most by participants outside the house in the year prior to hospitalisation. The self-reported footwear type was then categorised into adequate and inadequate according to footwear features recommended in guidelines for populations at risk of foot ulceration. Logistic regression identified factors independently associated with inadequate footwear in all inpatient participants, and diabetes and neuropathy subgroups.

RESULTS

Overall, 47% of a total of 726 inpatients wore inadequate outdoor footwear; 49% of the 171 in the diabetes subgroup and 43% of 159 in the neuropathy subgroup. Wearing inadequate outdoor footwear was independently associated (Odds Ratio (95% Confidence Interval)) with being female in the diabetes (2.7 (1.4-5.2)) and neuropathy subgroups (3.7 (1.8-7.9)) and being female (5.1 (3.7-7.1)), having critical peripheral arterial disease (2.5 (1.1-5.9)) and an amputation (0.3 (0.1-0.7)) in all inpatients (all, p<0.05).

CONCLUSIONS

Almost half of all inpatients at risk of foot ulceration reported wearing outdoor footwear most of the time that did not meet recommendations for prevention. We found women were much more likely to wear inadequate footwear. More work needs to be done to increase the uptake of footwear recommendations in these populations to prevent foot ulceration.

Distribution of the Highest Plantar Pressure Regions in Patients with Diabetes and Its Association with Peripheral Neuropathy, Gender, Age, and BMI: One Centre Study

The abnormal plantar pressure distribution and value play a key role in the formation of plantar calluses and diabetic foot ulcer. The prevalence of the highest pressure different distribution and its association with various factors among patients with diabetes is not well known. The study purpose was to evaluate the prevalence of different regions for the highest pressure on the sole and its association with selected factors among patients with diabetes. Medical records of nonulcer patients were retrospectively analysed. The relationship between pressure patterns on the sole obtained during a pedobarographic test as a semiquantitative assessment with colourful print analysis and neuropathy, gender, age, and BMI was searched. The most common location of the highest pressure was the central part of the forefoot. No association was found between the different highest pressure regions and age, sensory neuropathy, calluses, and foot deformities. The highest pressure on the lateral part of the foot and midfoot was observed more often in females and in patients with a BMI ≥ 35. The prevalence of the highest pressure on the forefoot was more common in patients with a BMI < 35. Conclusions. The most frequent regions of the highest pressure on the sole in patients with diabetes were the central part of the forefoot (2-3 metatarsal heads) with no simple relationship to the assessed variables other than BMI < 35. Female gender and higher BMI seem to be responsible for shifting the place of the highest pressure to other places of the foot.

An exploratory study on differences in cumulative plantar tissue stress between healing and non-healing plantar neuropathic diabetic foot ulcers

BACKGROUND

Mechanical stress is important in causing and healing plantar diabetic foot ulcers, but almost always studied as peak pressure only. Measuring cumulative plantar tissue stress combines plantar pressure and ambulatory activity, and better defines the load on ulcers. Our aim was to explore differences in cumulative plantar tissue stress between people with healing and non-healing plantar diabetic foot ulcers.

METHODS

We analyzed a subgroup of 31 patients from a randomized clinical trial, treated with a removable offloading device for their plantar diabetic forefoot ulcer. We measured in-device dynamic plantar pressure and daily stride count to calculate cumulative plantar tissue stress at the ulcer location and associated this with ulcer healing and ulcer surface area reduction at four weeks (Student's t and chi-square test for significance, Cohen's d for effect size).

FINDINGS

In 12 weeks, 68% (n = 21) of the ulcers healed and 32% (n = 10) did not. No statistically significant differences were found for cumulative plantar tissue stress, plantar pressure or ambulatory activity between people with healed and not-healed ulcers. Cumulative plantar tissue stress was 25% lower for people with healed ulcers (155 vs. 207 MPa·s/day; P = 0.71; Effect size: d = 0.29). Post-hoc analyses in the 27 patients who self-reported to be adherent to wearing the device showed that cumulative plantar tissue stress was 49% lower for those who reached ≥75% ulcer surface area reduction at four weeks (140 vs. 275 MPa·s/day; P = 0.09; d = 0.76); smaller differences and effect sizes were found for peak pressure (24%), peak pressure-time integral (30%) and ambulatory activity (26%); (P-value range: 0.14-0.97; Cohen's d range: 0.14-0.70).

INTERPRETATION

Measuring cumulative plantar tissue stress may provide insight beyond that obtained from plantar pressure or ambulatory activity alone, with regard to diabetic foot ulcer healing using removable offloading devices. These explorative findings provide baseline data for further studies on this relevant topic.

Diabetic Neuropathy and Gait: A Review

Diabetic peripheral neuropathy (DPN) is a major sequela of diabetes mellitus and may have a detrimental effect on the gait of people with this complication. DPN causes a disruption in the body's sensorimotor system and is believed to affect up to 50% of patients with diabetes mellitus, dependent on the duration of diabetes. It has a major effect on morbidity and mortality. The peripheral nervous system controls the complex series of events in gait through somatic and autonomic functions, careful balancing of eccentric and concentric muscle contractions and a reliance on the sensory information received from the plantar surface. In this literature review focussing on kinetics, kinematics and posture during gait in DPN patients, we have identified an intimate link between DPN and abnormalities in gait and demonstrated an increased risk in falls for older patients with diabetes. As such, we have identified a need for further research on the role of gait abnormalities in the development of diabetic foot ulceration and subsequent amputations.

Plantar pressures are elevated in people with longstanding diabetes-related foot ulcers during follow-up

Objective

High plantar pressures are implicated in the development of diabetes-related foot ulcers. Whether plantar pressures remain high in patients with chronic diabetes-related foot ulcers over time is uncertain. The primary aim of this study was to compare plantar pressures at baseline and three and six months later in participants with chronic diabetes-related foot ulcers (cases) to participants without foot ulcers (controls).

Methods

Standardised protocols were used to measure mean peak plantar pressure and pressure-time integral at 10 plantar foot sites (the hallux, toes, metatarsals 1 to 5, mid-foot, medial heel and lateral heel) during barefoot walking. Measurements were performed at three study visits: baseline, three and six months. Linear mixed effects random-intercept models were utilised to assess whether plantar pressures differed between cases and controls after adjusting for age, sex, body mass index, neuropathy status and follow-up time. Standardised mean differences (Cohen’s d) were used to measure effect size.

Results

Twenty-one cases and 69 controls started the study and 16 cases and 63 controls completed the study. Cases had a higher mean peak plantar pressure at several foot sites including the toes (p = 0.005, Cohen’s d = 0.36) and mid-foot (p = 0.01, d = 0.36) and a higher pressure-time integral at the hallux (p<0.001, d = 0.42), metatarsal 1 (p = 0.02, d = 0.33) and mid-foot (p = 0.04, d = 0.64) compared to controls throughout follow-up. A reduction in pressure-time integral at multiple plantar sites over time was detected in all participants (p<0.05, respectively).

Conclusions

Plantar pressures assessed during gait are higher in diabetes patients with chronic foot ulcers than controls at several plantar sites throughout prolonged follow-up. Long term offloading is needed in diabetes patients with diabetes-related foot ulcers to facilitate ulcer healing.

Vertical ground reaction force marker for Parkinson's disease

Parkinson’s disease (PD) patients regularly exhibit abnormal gait patterns. Automated differentiation of abnormal gait from normal gait can serve as a potential tool for early diagnosis as well as monitoring the effect of PD treatment. The aim of current study is to differentiate PD patients from healthy controls, on the basis of features derived from plantar vertical ground reaction force (VGRF) data during walking at normal pace. The current work presents a comprehensive study highlighting the efficacy of different machine learning classifiers towards devising an accurate prediction system. Selection of meaningful feature based on sequential forward feature selection, the swing time, stride time variability, and center of pressure features facilitated successful classification of control and PD gaits. Support Vector Machine (SVM), K-nearest neighbor (KNN), random forest, and decision trees classifiers were used to build the prediction model. We found that SVM with cubic kernel outperformed other classifiers with an accuracy of 93.6%, the sensitivity of 93.1%, and specificity of 94.1%. In comparison to other studies, utilizing same dataset, our designed prediction system improved the classification performance by approximately 10%. The results of the current study underscore the ability of the VGRF data obtained non-invasively from wearable devices, in combination with a SVM classifier trained on meticulously selected features, as a tool for diagnosis of PD and monitoring effectiveness of therapy post pathology.

Plantar pressures are higher in cases with diabetic foot ulcers compared to controls despite a longer stance phase duration

BACKGROUND

Current international guidelines advocate achieving at least a 30 % reduction in maximum plantar pressure to reduce the risk of foot ulcers in people with diabetes. However, whether plantar pressures differ in cases with foot ulcers to controls without ulcers is not clear. The aim of this study was to assess if plantar pressures were higher in patients with active plantar diabetic foot ulcers (cases) compared to patients with diabetes without a foot ulcer history (diabetes controls) and people without diabetes or a foot ulcer history (healthy controls).

METHODS

Twenty-one cases with diabetic foot ulcers, 69 diabetes controls and 56 healthy controls were recruited for this case-control study. Plantar pressures at ten sites on both feet and stance phase duration were measured using a pre-established protocol. Primary outcomes were mean peak plantar pressure, pressure-time integral and stance phase duration. Non-parametric analyses were used with Holm's correction to correct for multiple testing. Binary logistic regression models were used to adjust outcomes for age, sex and body mass index. Median differences with 95 % confidence intervals and Cohen's d values (standardised mean difference) were reported for all significant outcomes.

RESULTS

The majority of ulcers were located on the plantar surface of the hallux and toes. When adjusted for age, sex and body mass index, the mean peak plantar pressure and pressure-time integral of toes and the mid-foot were significantly higher in cases compared to diabetes and healthy controls (p < 0.05). The stance phase duration was also significantly higher in cases compared to both control groups (p < 0.05). The main limitations of the study were the small number of cases studied and the inability to adjust analyses for multiple factors.

CONCLUSIONS

This study shows that plantar pressures are higher in cases with active diabetic foot ulcers despite having a longer stance phase duration which would be expected to lower plantar pressure. Whether plantar pressure changes can predict ulcer healing should be the focus of future research. These results highlight the importance of offloading feet during active ulceration in addition to before ulceration.