Predictive value of foot pressure assessment as part of a population-based diabetes disease management program

A cross sectional pilot study utilising STrain Analysis and Mapping of the Plantar Surface (STAMPS) to measure plantar load characteristics within a healthy population

BACKGROUND

No in-shoe systems, measuring both components of plantar load (plantar pressure and shear stress) are available for use in patients with diabetes. The STAMPS (STrain Analysis and Mapping of the Plantar Surface) system utilises digital image correlation (DIC) to determine the strain sustained by a deformable insole, providing a more complete understanding of plantar shear load at the foot-surface interface.

RESEARCH QUESTIONS

What is the normal range and pattern of strain at the foot-surface interface within a healthy population as measured by the STAMPS system? Is STAMPS a valid tool to measure the effects of plantar load?

METHODS

A cross-sectional study of healthy participants was undertaken. Healthy adults without foot pathology or diabetes were included. Participants walked 20 steps with the STAMPS insole in a standardised shoe. Participants also walked 10 m with the Novel Pedar® plantar pressure measurement insole within the standardised shoe. Both measurements were repeated three times. Outcomes of interest were global and regional values for peak resultant strain (SMAG) and peak plantar pressure (PPP).

RESULTS

In 18 participants, median peak SMAG and PPP were 35.01 % and 410.6kPa respectively. The regions of the hallux and heel sustained the highest SMAG (29.31 % (IQR 24.56-31.39) and 20.50 % (IQR 15.59-24.12) respectively) and PPP (344.8kPa (IQR 268.3 - 452.5) and 279.3kPa (IQR 231.3-302.1) respectively). SMAG was moderately correlated with PPP (r= 0.65, p < 0.001). Peak SMAG was located at the hallux in 55.6 % of participants, at the 1st metatarsal head (MTH) in 16.7 %, the heel in 16.7 %, toes 3-5 in 11.1 % and the MTH2 in 5.6 %.

SIGNIFICANCE

The results demonstrate the STAMPS system is a valid tool to measure plantar strain. Further studies are required to investigate the effects of elevated strain and the relationship with diabetic foot ulcer formation.

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.

Texture differences of microchambers and macrochambers in heel pads between the elderly with and without diabetes

OBJECTIVE

This study aims to use the texture analysis of ultrasound images to distinguish the features of microchambers (a superficial thinner layer) and macrochambers (a deep thicker layer) in heel pads between the elderly with and without diabetes, so as to preliminarily explore whether texture analysis can identify the potential injury characteristics of deep tissue under the influence of diabetes before the obvious injury signs can be detected in clinical management.

METHODS

Ultrasound images were obtained from the right heel (dominant leg) of eleven elderly people with diabetes (DM group) and eleven elderly people without diabetes (Non-DM group). The TekScan system was used to measure the peak plantar pressure (PPP) of each participant. Six gray-level co-occurrence matrix (GLCM) features including contrast, correlation, dissimilarity, energy, entropy, homogeneity were used to quantify texture changes in microchambers and macrochambers of heel pads.

RESULTS

Significant differences in GLCM features (correlation, energy and entropy) of macrochambers were found between the two groups, while no significant differences in all GLCM features of microchambers were found between the two groups. No significant differences in PPP and tissue thickness in the heel region were observed between the two groups.

CONCLUSIONS

In the elderly with diabetes who showed no significant differences in PPP and plantar tissue thickness compared to those without diabetes, several texture features of ultrasound images were found to be significantly different. Our finding indicates that texture features (correlation, energy and entropy) of macrochambers could be used for early detection of soft tissue damage associated with diabetes.

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.

Predicting diabetic foot ulceration using routinely collected data in a foot clinic. What level of prognostic accuracy can be achieved?

This study aimed to investigate the efficacy of using routinely collected clinical data in predicting the risk of diabetic foot ulcer (DFU). The first objective was to develop a prognostic model based on the most important risk factors objectively selected from a set of 39 clinical measures. The second objective was to compare the prediction accuracy of the developed model against that of a model based on only the 3 risk factors that were suggested in the systematic review and meta-analyses study (PODUS). In a cohort study, a set of 12 continuous and 27 categorical data from patients (n = 203 M/F:99/104) who attended a specialised diabetic foot clinic were collected at baseline. These patients were then followed-up for 24 months during which 24 (M/F:17/7) patients had DFU. Multivariate logistic regression was used to develop a prognostic model using the identified risk factors that achieved p < 0.2 based on univariate logistic regression. The final prognostic model included 4 risk factors (Adjusted-OR [95% CI]; p) in total. Impaired sensation (116.082 [12.06-1117.287]; p = 0.000) and presence of callus (6.257 [1.312-29.836]; p = 0.021) were significant (p < 0.05), while having dry skin (5.497 [0.866-34.89]; p = 0.071) and Onychomycosis (6.386 [0.856-47.670]; p = 0.071) that stayed in the model were not significant. The accuracy of the model with these 4 risk factors was 92.3%, where sensitivity and specificity were 78.9%, and 94.0% respectively. The 78.9% sensitivity of our prognostic 4-risk factor model was superior to the 50% sensitivity that was achieved when the three risk factors proposed by PODUS were used. Also our proposed model based on the above 4 risk factors showed to predict the DFU with higher overall prognostic accuracy. These findings have implications for developing prognostic models and clinical prediction rules in specific patient populations to more accurately predict DFU.

Evaluating the use of a novel low-cost measurement insole to characterise plantar foot strain during gait loading regimes

Introduction: Under plantar loading regimes, it is accepted that both pressure and shear strain biomechanically contribute to formation and deterioration of diabetic foot ulceration (DFU). Plantar foot strain characteristics in the at-risk diabetic foot are little researched due to lack of measurement devices. Plantar pressure comparatively, is widely quantified and used in the characterisation of diabetic foot ulceration risk, with a range of clinically implemented pressure measurement devices on the market. With the development of novel strain quantification methods in its infancy, feasibility testing and validation of these measurement devices for use is required. Initial studies centre on normal walking speed, reflecting common activities of daily living, but evaluating response to differing gait loading regimes is needed to support the use of such technologies for potential clinical translation. This study evaluates the effects of speed and inclination on stance time, strain location and strain response using a low-cost novel strain measurement insole. Methods: The STrain Analysis and Mapping of the Plantar Aspect (STAMPS) insole has been developed, and feasibility tested under self-selected normal walking speeds to characterise plantar foot strain, with testing beyond this limited regime required. A treadmill was implemented to standardise speed and inclination for a range of daily plantar loading conditions. A small cohort, comprising of five non-diabetic participants, were examined at slow (0.75 m/s), normal (1.25 m/s) and brisk (2 m/s) walking speeds and normal speed at inclination (10% gradient). Results: Plantar strain active regions were seen to increase with increasing speed across all participants. With inclination, it was seen that strain active regions reduce in the hindfoot and show a tendency to forefoot with discretionary changes to strain seen. Stance time decreases with increasing speed, as expected, with reduced stance time with inclination. Discussion: Comparison of the strain response and stance time should be considered when evaluating foot biomechanics in diabetic populations to assess strain time interval effects. This study supports the evaluation of the STAMPS insole to successfully track strain changes under differing plantar loading conditions and warrants further investigation of healthy and diabetic cohorts to assess the implications for use as a risk assessment tool for DFU.

A fluoroscopic imaging-guided computational analyses to inform internal tissue loads within fat pad of the diabetic foot during gait

To accurately predict internal tissue loads for early diagnostics of diabetic foot ulcerations, a novel data-driven computational analysis was conducted. A dedicated dual fluoroscopic system was combined with a pressure mat to simultaneously characterize foot motions and soft tissue's material properties during gait. Finite element (FE) models of the heel pad of a diabetic patient were constructed with 3D trajectories of the calcaneus applied as boundary conditions to simulate gait events. The tensile and compressive stresses occurring in the plantar tissue were computed. Predictions of the layered tissue FE model with anatomically-accurate heel pad structures (i.e., fat and skin) were compared with those of the traditional lumped tissue (i.e., homogeneous) models. The influence of different material properties (patient-specific versus generic) on internal tissue stresses was also investigated. The results showed the peak tensile stresses in the layered tissue model were predominantly found in the skin and distributed towards the circumferential regions of the heel, while peak compressive stresses in the fat tissue-bone interface were up to 51.4% lower than those seen in the lumped models. Performing FE analyses at four different phases of walking revealed that ignorance of layered tissue structures resulted in an unphysiological increase of peak-to-peak value of stress fluctuation in the fat and skin tissue components. Thus, to produce more clinical-relevant predictions, foot FE models are suggested to include layered tissue structures of the plantar tissue for an improved estimation of internal stresses in the diabetic foot in gait.

STrain Analysis and Mapping of the Plantar Surface (STAMPS): A novel technique of plantar load analysis during gait

Diabetic foot ulceration is driven by peripheral neuropathy, resulting in abnormal foot biomechanics and elevated plantar load. Plantar load comprises normal pressure and tangential shear stress. Currently, there are no in-shoe devices measuring both components of plantar load. The STAMPS (STrain Analysis and Mapping of the Plantar Surface) system was developed to address this and utilises digital image correlation (DIC) to determine the strain sustained by a plastically deformable insole, providing an assessment of plantar load at the foot-surface interface during gait. STAMPS was developed as a multi-layered insole, comprising a deformable mid-layer, onto which a stochastic speckle pattern film is applied. A custom-built imaging platform is used to obtain high resolution pre- and post-walking images. Images are imported into commercially available DIC software (GOM Correlate, 2020) to obtain pointwise strain data. The strain and displacement data are exported and post-processed with custom analysis routines (MATLAB, Mathworks Inc.), to obtain the resultant global and regional peak strain (SMAG), antero-posterior strain (SAP) and medio-lateral strain (SML). To validate the core technique an experimental test process used a Universal Mechanical Tester (UMT) system (UMT TriboLab, Bruker) to apply controlled vertical and tangential load regimes to the proposed multi-layer insole. A pilot study was then conducted to assess the efficacy of using the STAMPS system to measure in-shoe plantar strain in three healthy participants. Each participant walked 10 steps on the STAMPS insole using a standardised shoe. They also walked 10 m in the same shoe using a plantar pressure measurement insole (Novel Pedar®) to record peak plantar pressure (PPP) as a gold-standard comparator. The results of the experimental validation tests show that with increased normal force, at a constant shear distance, SMAG increased in a linear fashion. Furthermore, they showed that with increased shear distance, at a constant force, SMAG increased. The results of the pilot study found participant 1 demonstrated greatest SMAG in the region toes 3-5 (15.31%). The highest mean SMAG for participant 2 was at the hallux (29.31%). Participant 3 exhibited highest strain in the regions of the first and second metatarsal heads (58.85% and 41.62% respectively). Increased PPP was strongly associated with increased SMAG with a Spearman's correlation coefficient 0.673 (p < 0.0001). This study has demonstrated the efficacy of a novel method to assess plantar load across the plantar surface of the foot. Experimental testing validated the sensitivity of the method to both normal pressure and tangential shear stress. This technique was successfully incorporated into the STAMPS insole to reliably measure and quantify the cumulative degree of strain sustained by a plastically deformable insole during a period of gait, which can be used to infer plantar loading patterns. Future work will explore how these measures relate to different pathologies, such as regions at risk of diabetic foot ulceration.

Characteristics of Pressure on the Apophysis in the Course of Paediatric Heel Pain-Preliminary Report

Increased pressure on the heel apophysis is often implicated as a cause of paediatric heel pain. However, there are few reports on the causes of the increased pressure and its origin. Therefore, the aim of this study was to analyse the distribution of pressure on the feet in children with heel pain. The study included 33 paediatric patients with non-traumatic heel pain, i.e., 24 boys (73%) and 9 girls (27%), aged on average 11.2 years (±3 years). Pedobarographic diagnostics proved a decrease in the pressure on the heels in relation to the ground and the transfer of the projection of the centre of gravity to the forefoot. While standing, the average contribution of the pressure on the heel was 0.52, SD = 0.14 in children with normal and reduced weight. In overweight children, the average pressure on the heel was higher (0.60, SD = 0.08), but the small number of children with this characteristic (n = 4) did not allow conclusions to be drawn in this area. Heel underload was also demonstrated during gait. However, the assessment of this aspect requires additional observational analyses in the field of propulsion and gait phases. The reduced pressure on the heel promotes apophysis traction, causing intracanal compression. Studies have shown that the causes of apophysis traction may be postural defects (in particular, forward inclination of body posture) and overpronation of the foot, or defects in the metatarsal area.

Accuracy of Foot Pressure Measurement on Predicting the Development of Foot Ulcer in Patients with Diabetes: A Systematic Review and Meta-Analysis

OBJECTIVE

Areas of the foot with diabetic ulcers have been observed to have greater plantar pressures compared to non-ulcerated. Pressures play an essential role in the mechanism of lesion, and their reduction is effective in prevention. We conducted a systematic review to evaluate pedobarography as a predictive tool for ulcer development, since there is still no consensus on this aspect.

METHODS

We searched PUBMED (MedLine), EMBASE, Scopus, Web of Science, CINAHL and Scielo for cohort studies that measured plantar pressure at baseline and verified ulcer development on follow-up. Pooled effects of accuracy, sensitivity, specificity and relative risk were calculated using the inverse variance method. Risk of bias was assessed using the QUADAS-2 tool.

RESULTS

Three studies (n = 2000) had enough information on accuracy to be included into a meta-analysis, and 4 (n = 2651) were analyzed using qualitative methods. Pooled sensitivity and specificity were found to be 0.63 (Confidence Interval (CI) 0.58-0.68) and 0.42 (CI 0.27-0.58), respectively. Pooled relative risk was 1.95 (CI 1.09-3.51). Risk of bias was low to uncertain.

CONCLUSIONS

Pedobarography in itself appears to have low accuracy in evaluating risk of ulceration. Several methodological heterogeneities were found, and the most optimal cut-off value is yet to be determined.

Effects of Walking Speeds and Durations on Peak Plantar Pressures

BACKGROUND

Walking at various speeds and durations may result in different peak plantar pressure (PPP). However, there is no study comparing the effect of walking speeds and durations on PPP. The purpose of this study was to explore whether different walking speeds and durations significantly change PPP and establish a normal response in healthy people.

METHODS

An in-shoe plantar pressure system was used to measure PPP under the first toe, first metatarsal, second metatarsal, and heel regions in 12 healthy, young people. All participants performed six walking trials at three speeds (3, 6, and 9 km/h) and for two durations (10 and 20 min). The 3 × 2 two-way analysis of variance was used to examine the main effects of speeds and durations and their interaction.

RESULTS

The results showed that walking speeds significantly affected PPP and that walking duration did not. No interaction between the walking speed and duration was observed. Peak plantar pressure values under the first toe and the first metatarsal head were significantly higher (P < .05) at 9 km/h (509.1 ± 314.2 kPa and 591.4 ± 302.4 kPa, respectively) than at 3 km/h (275.4 ± 168.7 kPa and 369.4 ± 205.4 kPa, respectively) after 10-min walking.

CONCLUSIONS

People at risk for foot ulcers may use slow and brisk walking for exercise to reduce PPP, thus reducing risk for foot ulcers. Our study demonstrated that slow running at 9 km/h significantly increases PPP.

A plantar surface shear strain methodology utilising Digital Image Correlation

The increase in the global diabetic population is leading to an increase in associated complications such as diabetic foot ulceration (DFU), associated amputations, morbidity, which substantial treatment costs. Early identification of DFU risk is therefore of great benefit. International guidelines recommend off-loading is the most important intervention for healing and prevention of DFU, with current research focused on pressure measurement techniques. The contribution of strain to DFU formation is not well understood due to challenges in measurement. The limited data available in the literature suggest that plantar strain is involved in ulcer formation. As a consequence, there is a need for plantar strain measurement systems to advance understanding and inform clinical treatment. A method was developed to determine plantar strain based on a Digital Image Correlation (DIC) approach. A speckle pattern is applied to the plantar aspect of the foot using a low ink transference method. A raised walkway with transparent panels is combined with a calibrated camera to capture images of the plantar aspect throughout a single stance phase. Plantar strain is then determined using 2D DIC and custom analysis summarises these data into clinically relevant metrics. A feasibility study involving six healthy participants was used to assess the efficacy of this new technique. The feasibility study successfully captured plantar surface strain characteristics continuously throughout the stance phase for all participants. Peak mean and averaged mean strains varied in location between participants when mapped into anatomical regions of plantar interest, ranging from the calcaneus to the metatarsal heads and hallux. This method provides the ability to measure plantar skin strain for use in both research and clinical environments. It has the potential to inform improved understanding of the role of strain in DFU formation. Further studies using this technique can support these ambitions and help differentiate between healthy and abnormal plantar strain regimes.

Digital Biomarkers of Gait and Balance in Diabetic Foot, Measurable by Wearable Inertial Measurement Units: A Mini Review

People with diabetic foot frequently exhibit gait and balance dysfunction. Recent advances in wearable inertial measurement units (IMUs) enable to assess some of the gait and balance dysfunction associated with diabetic foot (i.e., digital biomarkers of gait and balance). However, there is no review to inform digital biomarkers of gait and balance dysfunction related to diabetic foot, measurable by wearable IMUs (e.g., what gait and balance parameters can wearable IMUs collect? Are the measurements repeatable?). Accordingly, we conducted a web-based, mini review using PubMed. Our search was limited to human subjects and English-written papers published in peer-reviewed journals. We identified 20 papers in this mini review. We found preliminary evidence of digital biomarkers of gait and balance dysfunction in people with diabetic foot, such as slow gait speed, large gait variability, unstable gait initiation, and large body sway. However, due to heterogeneities in included papers in terms of study design, movement tasks, and small sample size, more studies are recommended to confirm this preliminary evidence. Additionally, based on our mini review, we recommend establishing appropriate strategies to successfully incorporate wearable-based assessment into clinical practice for diabetic foot care.

Effects of walking speeds and durations on the plantar pressure gradient and pressure gradient angle

BACKGROUND

Walking exercise has been demonstrated to improve health in people with diabetes. However, it is largely unknown the influences of various walking intensities such as walking speeds and durations on dynamic plantar pressure distributions in non-diabetics and diabetics. Traditional methods ignoring time-series changes of plantar pressure patterns may not fully capture the effect of walking intensities on plantar tissues. The purpose of this study was to investigate the effect of various walking intensities on the dynamic plantar pressure distributions. In this study, we introduced the peak pressure gradient (PPG) and its dynamic patterns defined as the pressure gradient angle (PGA) to quantify dynamic changes of plantar pressure distributions during walking at various intensities.

METHODS

Twelve healthy participants (5 males and 7 females) were recruited in this study. The demographic data were: age, 27.1 ± 5.8 years; height, 1.7 ± 0.1 m; and weight, 63.5 ± 13.5 kg (mean ± standard deviation). An insole plantar pressure measurement system was used to measure plantar pressures during walking at three walking speeds (slow walking 1.8 mph, brisk walking 3.6 mph, and slow running 5.4 mph) for two durations (10 and 20 min). The gradient at a location is defined as the unique vector field in the two-dimensional Cartesian coordinate system with a Euclidean metric. PGA was calculated by quantifying the directional variation of the instantaneous peak gradient vector during stance phase of walking. PPG and PGA were calculated in the plantar regions of the first toe, first metatarsal head, second metatarsal head, and heel at higher risk for foot ulcers. Two-way ANOVA with Fisher's post-hoc analysis was used to examine the speed and duration factors on PPG and PGA.

RESULTS

The results showed that the walking speeds significantly affect PPG (P < 0.05) and PGA (P < 0.05), and the walking durations does not. No interaction between the walking duration and speed was observed. PPG in the first toe region after 5.4 mph for either 10 or 20 min was significantly higher than 1.8 mph. Meanwhile, after 3.6 mph for 20 min, PPG in the heel region was significantly higher than 1.8 mph. Results also indicate that PGA in the forefoot region after 3.6 mph for 20 min was significantly narrower than 1.8 mph.

CONCLUSIONS

Our findings indicate that people may walk at a slow speed at 1.8 mph for reducing PPG and preventing PGA concentrated over a small area compared to brisk walking at 3.6 mph and slow running at 5.4 mph.

Predictive value of forefoot plantar pressure to predict reulceration in patients at high risk

AIMS

To analyze a plantar pressure cut-off point for diabetic foot reulceration beneath the metatarsal heads in patients with previous forefoot amputation.

METHODS

A one-year prospective study was conducted in a total of 105 patients at high risk for foot ulceration. Peak plantar pressure (PPP) and pressure-time integral (PTI) in the entire foot, the forefoot region, and each metatarsal head separately were registered. ROC curves were used to select the optimal diagnostic pressure cut-off points. Patients were follow-up monthly or until the development of an ulcer event.

RESULTS

A total of 52 (49.5%) patients developed a reulceration. Using ROC analyses for PPP in the full-foot and in the forefoot, did not predict reulceration beneath the metatarsal heads. Analyzing separately each metatarsal head all patients with values greater than or equal to 20.8 N/cm² at the 1st, 18.62 N/cm² for the 2nd, 18.85 at the 3rd, 17.88 at the 4th, and 12.2 at the 5th metatarsal heads will suffer a reulceration despite the use of orthopedic treatment with optimum values of sensitivity (from 100 to 87.5) and specificity (from 83.2 to 62.8).

CONCLUSION

Barefoot pressures beneath the metatarsal heads should be analyzed separately to predict the region at risk of reulceration.

A metatranscriptomic approach to explore longitudinal tissue specimens from non-healing diabetes related foot ulcers

Cellular mechanisms and/or microbiological interactions which contribute to chronic diabetes related foot ulcers (DRFUs) were explored using serially collected tissue specimens from chronic DRFUs and control healthy foot skin. Total RNA was isolated for next-generation sequencing. We found differentially expressed genes (DEGs) and enriched hallmark gene ontology biological processes upregulated in chronic DRFUs which primarily functioned in the host immune response including: (i) Inflammatory response; (ii) TNF signalling via NFKB; (iii) IL6 JAK-STAT3 signalling; (iv) IL2 STAT5 signalling and (v) Reactive oxygen species. A temporal analysis identified RN7SL1 signal recognition protein and IGHG4 immunoglobulin protein coding genes as being the most upregulated genes after the onset of treatment. Testing relative temporal changes between healing and non-healing DRFUs identified progressive upregulation in healed wounds of CXCR5 and MS4A1 (CD20), both canonical markers of lymphocytes (follicular B cells/follicular T helper cells and B cells, respectively). Collectively, our RNA-seq data provides insights into chronic DRFU pathogenesis.

Body mass index and maximum available midfoot motion are associated with midfoot angle at peak heel rise in people with type 2 diabetes mellitus and peripheral neuropathy

PURPOSE

Midfoot movement dysfunction, as measured by heel rise performance, is associated with midfoot deformity in people with diabetes and peripheral neuropathy. Understanding contributors of midfoot movement dysfunction may help clinicians understand deformity progression. The purpose of this study was to determine the factors associated with midfoot angle at peak heel rise.

METHODS

The outcomes of fifty-eight participants with type 2 diabetes mellitus and peripheral neuropathy were analyzed. Midfoot (forefoot on hindfoot) sagittal kinematics during unilateral heel rise task were measured using 3-dimensional motion analysis. A multivariate linear regression model was used to predict midfoot sagittal movements at peak heel rise. Independent variables that were entered in the model were (in order of entry): age, body mass index, intrinsic foot muscle volume, and maximum available midfoot plantarflexion range of motion. Intrinsic foot muscle volume was obtained from magnetic resonance imaging and maximum available midfoot motion was measured during non-weightbearing plantarflexion using 3-dimensional motion analysis.

RESULTS

Body mass index (R² = 30.5%, p < 0.001) and maximum available midfoot plantarflexion range of motion (R² = 10.9%, p = 0.001) were significant factors that accounted for 41.4% of variance of midfoot angle at peak heel rise, while age and intrinsic foot muscle volume were not significant predictors.

CONCLUSIONS

Greater body mass index and less available midfoot plantarflexion range of motion were associated with greater midfoot movement dysfunction. These two significant predictors are potentially modifiable, suggesting possible improvements in midfoot movements with reduction in body weight and increasing midfoot plantarflexion range of motion. Health care professionals should consider patient's weight and joint motion when prescribing foot exercise(s) to prevent excessive midfoot collapse during weightbearing tasks.

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.

Effectiveness of combined modulated ultrasound and electric current stimulation to treat diabetic foot ulcers

OBJECTIVE

The use of combined ultrasound and electrostimulation (CUSECS) as an adjunct therapy for diabetic foot ulcers (DFUs) is a relatively new concept. This study aimed to investigate if combined ultrasound and electrostimulation is an effective adjunctive treatment for hard-to-heal DFUs when compared with standard wound care.

METHODS

A randomised controlled pilot study design was used. Patients with hard-to-heal DFUs from two centres were sequentially randomised. For 8 weeks, the experimental group received CUSECS and standard wound care treatment twice a week. The control group received standard wound care treatment once a week. Wound changes were documented using photography, which also facilitated wound size measurement. Self-efficacy, economic cost, quality of life and reoccurrence rates were analysed as secondary objectives.

RESULTS

The experimental group (n=6) achieved a higher rate of mean wound healing (mean difference (MD): 0.49) when compared to the control group (n=5, MD: 0.01). Two participants completed full healing in the experimental group and one in the control group. There were no statistically significant findings because of the small sample size. There were no direct adverse reactions to this therapy. Quality of life scores improved in the treatment group. There was no significant change in self-efficacy scores. Costs were higher in the experimental group; however, the healing rate was quicker, which could be extrapolated to cost reductions over time.

CONCLUSION

Results suggest that CUSECS may be a useful adjunctive therapy for treatment of hard-to-heal DFUs. Further large-scale studies are needed to ascertain the effectiveness of CUSECS. The findings here are inconclusive but indicate that CUSECS may offer promise as a treatment.

Teaching Wound Care to Family Caregivers: An overview of methods to use to promote wound healing

This article is part of a series, Supporting Family Caregivers: No Longer Home Alone, published in collaboration with the AARP Public Policy Institute. Results of focus groups, conducted as part of the AARP Public Policy Institute's No Longer Home Alone video project, supported evidence that family caregivers aren't given the information they need to manage the complex care regimens of family members. This series of articles and accompanying videos aims to help nurses provide caregivers with the tools they need to manage their family member's health care at home. The articles in this new installment of the series provide simple and useful instructions that nurses should reinforce with family caregivers who perform wound care tasks. Each article also includes an informational tear sheet-Information for Family Caregivers-that contains links to instructional videos. To use this series, nurses should read the article first, so they understand how best to help family caregivers, and then encourage caregivers to watch the videos and ask questions. For additional information, see Resources for Nurses.

Stress-Reducing Psychological Interventions as Adjuvant Therapies for Diabetic Chronic Wounds

BACKGROUND

Diabetic foot ulcers (DFUs) are a major complication of diabetes mellitus and a leading cause of lower limb amputation. Interventions to reduce psychological stress may have the potential to improve self-care and greatly reduce the morbidity and mortality associated with DFU. This review is focused on the consequences of psychological stress in wound healing and reflects on the effects of currently used psychological stress-reducing interventions in patients with DFU, proposing new applications for currently used stress-reduction interventions.

RESULTS

Stress is a natural and fundamental survival mechanism that becomes harmful when chronic. DFU is associated with high levels of anxiety and chronic psychological stress. Chronic stressinduced cortisol and adrenaline release impair wound healing, independently of the stressor. Psychological stress-reducing interventions, such as relaxation with guided imagery, biofeedback-assisted relaxation, mindfulness-based strategies, and hypnosis, can lead to a reduction in perceived stress and improve wound healing by reducing wound inflammation and pain while improving glycemic control. All stress reduction interventions also lead to pain relief and improved patient's quality of life.

CONCLUSION

Psychological stress-reducing interventions are promising adjuvant therapies for DFU. Their clinical application can improve self-care by tackling patient's expectations, anxieties, and fears. They can also help patients manage stress and pain while reducing wound inflammation and improving wound healing.

Risk Factors for Diabetic Peripheral Neuropathy, Peripheral Artery Disease, and Foot Deformity Among the Population With Diabetes in Beijing, China: A Multicenter, Cross-Sectional Study

Diabetic peripheral neuropathy (DPN), peripheral artery disease (PAD), and foot deformity are the most common causes of diabetic foot, which can considerably worsen the patient's quality of life. In this study, we aimed to investigate the prevalence and risk factors associated with DPN, PAD, and foot deformity among patients with diabetes living in Beijing, China. In total, 3,898 diabetes patients from 11 hospitals in Beijing were evaluated using questionnaires and physical examinations, and 3,758 patients were included in the analysis. We compared the demographic, clinical, biological characteristics, and comorbidities of patients with and without DPN, PAD, or foot deformity, and used binary logistic regression analysis to identify potential factors associated with these outcomes. Overall, 882 patients (23.5%) had DPN, 437 patients (11.6%) had PAD, and 1,117 patients (29.7%) had foot deformities, including callus. The risk factors for DPN included: age ≥40 years, a ≥10+year duration of diabetes, a body mass index of <18.5 kg/m² or ≥24 kg/m², a systolic blood pressure (SBP) of ≥140 mm Hg, a hemoglobin A_1c (HbA_1c) level of ≥7%, chronic kidney disease, and cerebrovascular disease. The risk factors for PAD included: a 15+ year diabetes duration, a body mass index of <18.5 kg/m², a SBP of ≥140 mm Hg, a HbA_1c level of ≥7%, chronic kidney disease, coronary heart disease, and cerebrovascular disease. The risk factors for skeletal foot deformities included: women, age ≥40 years, a SBP ≥140 mm Hg, and hyperlipidemia. The risk factors for callus formation included: women, a SBP ≥140 mm Hg, and hyperlipidemia. In conclusion, the prevalence of foot deformities was higher than DPN and PAD in patients with diabetes. Managing the risk factors for DPN, PAD, and foot deformity is important for reducing the risk of diabetic foot.

Plantar Pressure Distribution Among Diabetes and Healthy Participants: A Cross-sectional Study

Background:

Plantar Pressure distribution refers to the distribution of force over the sole of the foot. Recently many studies indicate plantar pressure distribution assisted in determining and managing the impairment related to musculoskeletal disorders.

Methods:

This cross-sectional study was conducted with forty participants (20 diabetes type 2 patients +20 healthy) from Imam Abdulrahman bin Faisal University. All the measurements were taken in the morning session. To measure height and weight, participants took off their shoes and stood on the stadiometer. The body mass index determined with the help of a bioelectric impedance device to get the health level of the participants—Proclaimed diabetes type 2 patients selected for the data collection. Tekscan's Mobile Mat was used to determine the plantar pressure of healthy and diabetes participants.

Results:

The finding revealed that diabetes participants have more pressure in the mid-foot section, whereas healthy participants showed more pressure on the heel section. The metatarsal section showed similar types of pressure distribution in both participants. The result also revealed that diabetes participants have more peak pressures, time integral, and gradient than healthy participants. Significant differences between diabetes and healthy participants were existing.

Conclusions:

The findings highlight the importance of measuring plantar pressure distribution since these are known to incorporate in the main parts of the foot and thus provide a shred of constructive evidence for the total load exposer of a single leg static task.

Machine learning prediction of diabetic foot ulcers in the inpatient population

BACKGROUND

The objective of this study was to create an algorithm that could predict diabetic foot ulcer (DFU) incidence in the in-patient population.

MATERIALS AND METHODS

The Nationwide Inpatient Sample datasets were examined from 2008 to 2014. The International Classification of Diseases 9th Edition Clinical Modification (ICD-9-CM) and the Agency for Healthcare Research and Quality comorbidity codes were used to assist in the data collection. Chi-square testing was conducted, using variables that positively correlated with DFUs. For descriptive statistics, the Student T-test, Wilcoxon rank sum test, and chi-square test were used. There were six predictive variables that were identified. A decision tree model CTREE was utilized to help develop an algorithm.

RESULTS

326,853 patients were noted to have DFU. The major variables that contributed to this diagnosis (both with p < 0.001) were cellulitis (OR 63.87, 95% CI [63.87-64.49]) and Charcot joint (OR 25.64, 95% CI [25.09-26.20]). The model performance of the six-variable testing data was 79.5% (80.6% sensitivity and 78.3% specificity). The area under the curve (AUC) for the 6-variable model was 0.88.

CONCLUSION

We developed an algorithm with a 79.8% accuracy that could predict the likelihood of developing a DFU.

Using Manchester Scale classification of Hallux Valgus as a valuable tool in determining appropriate risk categorization during initial diabetic foot screening in primary health care settings

Limitations have been identified in the current state of primary care practises with regards to identifying and correctly categorizing foot deformity and its associated risk of developing foot ulcers in patients with diabetes. This study aims to bridge these gaps through the implementation of additional categorization tools to be made available for primary care professionals. This study thus analysed the relationship between foot pressure distribution and amount in patients with diabetes with Hallux Valgus foot deformity, and its different stages, in order to better understand the clinical applications of the Manchester Scale. Statistically significant data in pressure distribution (P < 0.05) was found in all three severity groups identified by the Manchester Scale (Mild, Moderate and Severe) when compared to a No deformity group. However, only the Severe Hallux Valgus group crossed the threshold over 500 kPa in the area of first metatarsal bone. Further research should aim to analyse pressure distribution and amount in patients with both diabetes and diabetic neuropathy of all stages of Hallux Valgus.

Analysis of Plantar Pressure Pattern after Metatarsal Head Resection. Can Plantar Pressure Predict Diabetic Foot Reulceration?

To evaluate the metatarsal head that was associated with the highest plantar pressure after metatarsal head resection (MHR) and the relations with reulceration at one year, a prospective was conducted with a total of sixty-five patients with diabetes who suffered from the first MHR and with an inactive ulcer at the moment of inclusion. Peak plantar pressure and pressure time integral were recorded at five specific locations in the forefoot: first, second, third, fourth, and fifth metatarsal heads. The highest value of the four remaining metatarsals was selected. After resection of the first metatarsal head, there is a displacement of the pressure beneath the second metatarsal head (p < 0.001). Following the resection of the minor metatarsal bones, there was a medial displacement of the plantar pressure. In this way, plantar pressure was displaced under the first metatarsal head following resection of the second or third head (p = 0.001) and under the central heads after resection of the fourth or fifth metatarsal head (p < 0.009 and p < 0.001 respectively). During the one-year follow-up, patients who underwent a metatarsal head resection in the first and second metatarsal heads suffered transfer lesion in the location with the highest pressure. Patients who underwent a minor metatarsal head resection (second–fifth metatarsal heads) showed a medial transference of pressure. Additionally, following the resection of the first metatarsal head there was a transference of pressure beneath the second metatarsal head. Increase of pressure was found to be a predictor of reulceration in cases of resection of the first and second metatarsal heads.

Predictive values of foot plantar pressure assessment in patients with midfoot deformity secondary to Charcot neuroarthropathy

AIMS

The principal aim of this study was to identify a cut-off point along the spectrum of peak plantar midfoot pressure that has an optimum combination of sensitivity and specificity to screen for neuropathic ulceration in patients with Charcot neuroarthropathy (CN).

METHODS

A 1-year outcome study was performed in twenty-five patients with diabetes, affected with chronic CN midfoot deformity. Peak plantar pressure (PPP) and pressure/time Integral (PTI) in the midfoot region were registered. For selecting the optimal diagnostic cut-off points on the scale of pressure measurement, ROC curves were used.

RESULTS

Twelve (48%) patients developed a plantar midfoot ulcer. Baseline PPP (24.04 ± 6.33 Vs. 12.85 ± 3.29 N/cm²) and PTI (11.89 ± 4.60 Vs. 5.42 ± 2.26 N/cm²/s) were significantly higher in the ulcerated group (p < .001 and p < .001, respectively). Using ROC analyses, optimal cut-off point for PPP was 16.45 N/cm², yielding a sensitivity of 92% and a specificity of 85%; and for PTI, optimal cut-off point was 7.2 N/cm²/s, yielding a sensitivity of 92% and a specificity of 77%.

CONCLUSIONS

Patients with CN midfoot deformity with cut-off values for PPP of 16.45 N/cm² and PTI of 7.2 N/cm²/s showed an elevated risk of neuropathic ulceration in the plantar area of the midfoot.

Midfoot and ankle motion during heel rise and gait are related in people with diabetes and peripheral neuropathy

BACKGROUND

Midfoot and ankle movement dysfunction in people with diabetes mellitus and peripheral neuropathy (DMPN) is associated with midfoot deformity and increased plantar pressures during gait. If midfoot and ankle motion during heel rise and push-off of gait have similar mechanics, heel rise performance could be a clinically feasible way to identify abnormal midfoot and ankle function during gait.

RESEARCH QUESTION

Is midfoot and ankle joint motion during a heel rise associated with midfoot and ankle motion at push-off during gait in people with DMPN?

METHODS

Sixty adults with DMPN completed double-limb heel rise, single-limb heel rise, and walking. A modified Oxford multi-segment foot model (forefoot, hindfoot, shank) was used to analyze midfoot (forefoot on hindfoot) and ankle (hindfoot on shank) sagittal angle during heel rise and gait. Pearson correlation was used to test the relationship between heel rise and gait kinematic variables (n = 60). Additionally, we classified 60 participants into two subgroups based on midfoot and ankle position at peak heel rise: midfoot and ankle dorsiflexed (dorsiflexed; n = 23) and midfoot and ankle plantarflexed (plantarflexed; n = 20). Movement trajectories of midfoot and ankle motion during single-limb heel rise and gait of the subgroups were examined.

RESULTS

Peak double-limb heel rise and gait midfoot and ankle angles were significantly correlated (r = 0.49 and r = 0.40, respectively). Peak single-limb heel rise and gait midfoot and ankle angles were significantly correlated (r = 0.63 and r = 0.54, respectively). The dorsiflexed subgroup, identified by heel rise performance showed greater midfoot and ankle dorsiflexion during gait compared to the plantarflexed subgroup (mean difference between subgroups: midfoot 3°, ankle 3°).

SIGNIFICANCE

People with DMPN who fail to plantarflex the midfoot and ankle during heel rise have difficulty plantarflexing the midfoot and ankle during gait. Utilizing a heel rise task may help identify midfoot and ankle dysfunction associated with gait in people with DMPN.

A Surgical Approach to Location-specific Neuropathic Foot Ulceration

The management of pedal ulcerations is often challenging because of a failure to correct underlying biomechanical deformities. Without correcting the biomechanical driving force creating the increased plantar pressures, it is unlikely for routine wound care to provide lasting solutions to pedal ulcerations. Patients with diabetes often experience glycosylation of their tendons, leading to contracture and pursuant deformity, creating imbalanced pressure distributions and eventual plantar ulceration. This article evaluates the efficacy of various lower extremity tendon transfers to balance the foot and redistribute plantar pressures to prevent or heal ulceration.

Prevalence and Risk Evaluation of Diabetic Complications of the Foot Among Adults With Type 1 and Type 2 Diabetes in a Large Canadian Population (PEDAL Study)

OBJECTIVES

The lower limb complications of diabetes contribute significantly to patient morbidity and health-care costs in Canada. Despite practice guidelines, awareness of and screening for modifiable early pathologies has been inconsistent. Our study objective was to determine the prevalence and types of early foot pathology in a large, Canadian, community care-based diabetes population.

METHODS

This study was a retrospective, observational analysis of the LMC Diabetes & Endocrinology foot care program launched in 2017. We examined foot pathologies associated with vascular, nerve, nail and dermatologic complications, as well as foot deformities. Individuals ≥18 years of age and with diabetes, assessed by an LMC chiropodist in Ontario between February 2018 and April 2019, were included in the analysis.

RESULTS

Of the 5,084 individuals assessed, 470 with type 1 diabetes and 3,903 with type 2 diabetes met the study criteria. Mean age, body mass index and diabetes duration was 61.5 years, 31.3 kg/m² and 13.9 years, respectively. Reduced pedal pulses, sensory neuropathy and onychomycosis were reported in 8.9%, 16.7% and 14.5% of those in the type 1 diabetes group, and 19.4%, 26.6% and 28.7% of those in the type 2 group, respectively. Hyperkeratosis was present in 51% and foot deformities were present in 44.5% among both groups. Foot ulcer prevalence was 1.7% and pedal pulses, sensory neuropathy, hyperkeratosis and onychauxis, adjusted for age, sex, body mass index and diabetes duration, were each significantly associated with ulceration.

CONCLUSIONS

In a large foot screening program of community-based adults with diabetes, modifiable early foot pathologies were prevalent and provided further evidence of the value of consistent screening to alleviate the morbidity and economic burden of lower limb complications.

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.

Predicting the risk of future diabetic foot ulcer occurrence: a prospective cohort study of patients with diabetes in Tanzania

OBJECTIVES

The aim of this study was to identify the parameters that predict the risk of future foot ulcer occurrence in patients with diabetes.

RESEARCH DESIGN AND METHODS

1810 (male (M)/female (F): 1012/798) patients, with no foot ulcer at baseline, participated in this study. Data from a set of 28 parameters were collected at baseline. During follow-up, 123 (M/F: 68/55) patients ulcerated. Survival analyses together with logistic regression were used to identify the parameters that could predict the risk of future diabetic foot ulcer occurrence.

RESULTS

A number of parameters (HR (95% CI)) including neuropathy (2.525 (1.680 to 3.795)); history of ulceration (2.796 (1.029 to 7.598)); smoking history (1.686 (1.097 to 2.592)); presence of callus (1.474 (0.999 to 2.174)); nail ingrowth (5.653 (2.078 to 15.379)); foot swelling (3.345 (1.799 to 6.218)); dry skin (1.926 (1.273 to 2.914)); limited ankle (1.662 (1.365 to 2.022)) and metatarsophalangeal (MTP) joint (2.745 (1.853 to 4.067)) ranges of motion; and decreased (3.141 (2.102 to 4.693)), highly decreased (5.263 (1.266 to 21.878)), and absent (9.671 (5.179 to 18.059)) sensation to touch; age (1.026 (1.010 to 1.042)); vibration perception threshold (1.079 (1.060 to 1.099)); duration of diabetes (1.000 (1.000 to 1.000)); and plantar pressure at the first metatarsal head (1.003 (1.001 to 1.005)), temperature sensation (1.019 (1.004 to 1.035)) and temperature tolerance (1.523 (1.337 to 1.734)) thresholds to hot stimuli and blood sugar level (1.027 (1.006 to 1.048)) were all significantly associated with increased risk of ulceration. However, plantar pressure underneath the fifth toe (0.990 (0.983 to 0.998)) and temperature sensation (0.755 (0.688 to 0.829)) and temperature tolerance (0.668 (0.592 to 0.0754)) thresholds to cold stimuli showed to significantly decrease the risk of future ulcer occurrence. Multivariate survival model indicated that nail ingrowth (4.42 (1.38 to 14.07)); vibration perception threshold (1.07 (1.04 to 1.09)); dry skin status (4.48 (1.80 to 11.14)); and temperature tolerance threshold to warm stimuli (1.001 (1.000 to 1.002)) were significant predictors of foot ulceration risk in the final model. The mean time to ulceration was significantly (p<0.05) shorter for patients with: dry skin (χ²=11.015), nail ingrowth (χ²=14.688), neuropathy (χ²=21.284), or foot swelling (χ²=16.428).

CONCLUSION

Nail ingrowth and dry skin were found to be strong indicators of vulnerability of patients to diabetic foot ulceration. Results highlight that assessments of neuropathy in relation to both small and larger fiber impairment need to be considered for predicting the risk of diabetic foot ulceration.

Plantar Fasciitis in Diabetic Foot Patients: Risk Factors, Pathophysiology, Diagnosis, and Management

Plantar fasciitis (PF) is a common degenerative disorder and a frequent cause of heel pain, mostly affecting patients in their fourth and fifth decades. Diabetic patients are particularly at risk due to the presence of common risks and co-morbidities such as obesity or a sedentary lifestyle. The diagnosis of PF is mainly clinical. Imaging is not recommended for the initial approach. The initial management is conservative and should include physiotherapy, off-loading, stretching exercises, and nonsteroidal anti-inflammatory drugs. Glucocorticoid injections or surgery is an option at a later stage in recalcitrant cases. The overall management of PF does not differ between patients with diabetic foot problems and non-diabetic patients, although the details can differ. This narrative review summarizes the state of the art in terms of the risk factors, pathophysiology, diagnosis, assessment, and management of PF in diabetic patients.

Prediction of Diabetic Foot Ulceration: The Value of Using Microclimate Sensor Arrays

BACKGROUND

Accurately predicting the risk of diabetic foot ulceration (DFU) could dramatically reduce the enormous burden of chronic wound management and amputation. Yet, the current prognostic models are unable to precisely predict DFU events. Typically, efforts have focused on individual factors like temperature, pressure, or shear rather than the overall foot microclimate.

METHODS

A systematic review was conducted by searching PubMed reports with no restrictions on start date covering the literature published until February 20, 2019 using relevant keywords, including temperature, pressure, shear, and relative humidity. We review the use of these variables as predictors of DFU, highlighting gaps in our current understanding and suggesting which specific features should be combined to develop a real-time microclimate prognostic model.

RESULTS

The current prognostic models rely either solely on contralateral temperature, pressure, or shear measurement; these parameters, however, rarely reach 50% specificity in relation to DFU. There is also considerable variation in methodological investigation, anatomical sensor configuration, and resting time prior to temperature measurements (5-20 minutes). Few studies have considered relative humidity and mean skin resistance.

CONCLUSION

Very limited evidence supports the use of single clinical parameters in predicting the risk of DFU. We suggest that the microclimate as a whole should be considered to predict DFU more effectively and suggest nine specific features which appear to be implicated for further investigation. Technology supports real-time in-shoe data collection and wireless transmission, providing a potentially rich source of data to better predict the risk of DFU.

A Review of Wearable Sensor Systems to Monitor Plantar Loading in the Assessment of Diabetic Foot Ulcers

Diabetes is highly prevalent throughout the world and imposes a high economic cost on countries at all income levels. Foot ulceration is one devastating consequence of diabetes, which can lead to amputation and mortality. Clinical assessment of diabetic foot ulcer (DFU) is currently subjective and limited, impeding effective diagnosis, treatment and prevention. Studies have shown that pressure and shear stress at the plantar surface of the foot plays an important role in the development of DFUs. Quantification of these could provide an improved means of assessment of the risk of developing DFUs. However, commercially-available sensing technology can only measure plantar pressures, neglecting shear stresses and thus limiting their clinical utility. Research into new sensor systems which can measure both plantar pressure and shear stresses are thus critical. Our aim in this paper is to provide the reader with an overview of recent advances in plantar pressure and stress sensing and offer insights into future needs in this critical area of healthcare. Firstly, we use current clinical understanding as the basis to define requirements for wearable sensor systems capable of assessing DFU. Secondly, we review the fundamental sensing technologies employed in this field and investigate the capabilities of the resultant wearable systems, including both commercial and research-grade equipment. Finally, we discuss research trends, ongoing challenges and future opportunities for improved sensing technologies to monitor plantar loading in the diabetic foot.

Innovative intelligent insole system reduces diabetic foot ulcer recurrence at plantar sites: a prospective, randomised, proof-of-concept study

BACKGROUND

Prevention of diabetic foot ulcer recurrence in high risk patients, using current standard of care methods, remains a challenge. We hypothesised that an innovative intelligent insole system would be effective in reducing diabetic foot ulcer recurrence in such patients.

METHODS

In this prospective, randomised, proof-of-concept study, patients with diabetes, and with peripheral neuropathy and a recent history of plantar foot ulceration were recruited from two multidisciplinary outpatient diabetic foot clinics in the UK, and were randomly assigned to either intervention or control. All patients received an insole system, which measured plantar pressure continuously during daily life. The intervention group received audiovisual alerts via a smartwatch linked to the insole system and offloading instructions when aberrant pressures were detected; the control group did not receive any alerts. The primary outcome was plantar foot ulcer occurrence within 18 months. This trial is registered with ISRCTN, ISRCTN05585501, and is closed to accrual and complete.

FINDINGS

Between March 18, 2014, and Dec 20, 2016, 90 patients were recruited and consented to the study, and 58 completed the study. At follow-up, ten ulcers from 8638 person-days were recorded in the control group and four ulcers from 11 835 person-days in the intervention group: a 71% reduction in ulcer incidence in the intervention group compared with the control group (incidence rate ratio 0·29, 95% CI, 0·09-0·93; p=0·037). The number of patients who ulcerated was similar between groups (six of 26 [control group] vs four of 32 [intervention group]; p=0·29); however, individual plantar sites ulcerated more often in the control group (ten of 416) than in the intervention group (four of 512; p=0·047). In an exploratory analysis of good compliers (n=40), ulcer incidence was reduced by 86% in the intervention group versus control group (incidence rate ratio 0·14, 95% CI 0·03-0·63; p=0·011). In the exploratory analysis, plantar callus severity (change from baseline to 6 months) was greater in re-ulcerating patients (6·5, IQR 4·0-8·3) than non-re-ulcerating patients (2·0, 0·0-4·8; p=0·040).

INTERPRETATION

To our knowledge, this study is the first to show that continuous plantar pressure monitoring and dynamic offloading guidance, provided by an innovative intelligent insole system, can lead to a reduction in diabetic foot ulcer site recurrence.

FUNDING

Diabetes UK and Orpyx Medical Technologies.

Relationship between range of motion of foot joints and amount of physical activity in middle-aged male diabetic patients

[Purpose] This study aimed to verify the relationship between foot range of motion and the amount of physical activity in diabetic patients. [Participants and Methods] There were twenty-eight male patients with diabetes (age ranged from 50 to 69 years old) and 10 healthy, non-diabetic male individuals within the same age range in the diabetes group and control group, respectively. The passive ranges of motion of the following joints were measured in the right foot of each participant: the ankle joint, the first metatarsophalangeal joint, and the subtalar joint. The amount of daily physical activity was estimated using the short Japanese version of the International Physical Activity Questionnaire. [Results] The mean range of motion of the ankle joints in the diabetic and control groups was 55.4 ± 8.4° and 69.1 ± 9.2°, respectively, whereas the mean range of motion of the first metatarsophalangeal joints in the diabetic and control groups was 82.9 ± 9.6° and 96.3 ± 8.9°, respectively. The diabetic group showed a significantly higher restriction in joint range of motion than did the control group. The amount of physical activity was a contributing factor toward the ankle range of motion according to multiple regression analysis. [Conclusion] We determined that the range of motion in the ankle joints of diabetic patients was affected by their level of physical activity.

Current concepts in curative surgery for diabetic forefoot ulcers

Forefoot ulcerations in patients with diabetes are quite common. Underlying mechanical deformities of the foot in combination with neuropathy are the most important risk factors for ulcer development and adequate offloading is the mainstay of management. Most ulcers heal with local wound care, adequate blood supply, and pressure relief. If a foot deformity cannot be accommodated, ulcers will not heal or may recur. In this case, surgical correction of deformity is necessary. This paper reviews the most common procedures supported by medical evidence to heal neuropathic forefoot ulcers.

Can a combination of lifestyle and clinical characteristics explain the presence of foot ulcer in patients with diabetes?

AIMS

The aim of this study was to identify the biomechanical, neurological and clinical parameters along with other demographics and lifestyle risk factors that could explain the presence of foot ulcer in patients with diabetes in Africa.

METHODS

A total of 1270 (M/F:696/574) patients; 77(M/F:53/24) with ulcerated vs 1193 (M/F: 643/550) with non-ulcerated feet; participated in this study. A set of 28 parameters were collected and compared between the participants with and without active foot ulcers. Multivariate logistic regression was utilised to develop an explanatory model for foot ulceration.

RESULTS

Foot swelling (χ2(1,n = 1270) = 265.9,P = 0.000,Phi = 0.464) and impaired sensation to monofilament (χ2(2,n = 1270) = 114.2,P = 0.000,Cramer'sV = 0.300) showed strong association with presence of ulceration. A lower Temperature sensitivity to cold stimuli and limited ankle joint mobility were observed to be significant (P < 0.05) contributors to ulceration. The logistic regression model can justify the presence of foot ulceration with 95.3% diagnostic accuracy, 99.1% specificity and 37.3% sensitivity.

CONCLUSION

Participants with ulcerated foot show distinct characteristics in few foot related parameters. Swollen foot, limited ankle mobility, and peripheral sensory neuropathy were significant characteristics of patients with diabetic foot ulcer. One out of three patients with ulcerated foot showed common characteristics that could be justified by the model.

Neurovascular Response to Pressure in Patients With Diabetic Foot Ulcer

Diabetic foot ulcer (DFU) is a problem worldwide, and prevention is crucial. We hypothesized that the inability of the skin to respond to pressure is involved in DFU pathogenesis and could be an important predictive factor to take into account. We included 29 patients with DFU and 30 patients with type 2 diabetes without DFU. Neuropathy and skin blood flow at rest were assessed in response to acetylcholine, sodium nitroprusside, local heating (42°C), and to nonnoxious locally applied pressure. Results were compared with those obtained from 10 healthy age-matched control subjects. Vasodilatation in response to pressure was significantly impaired in both groups with diabetes compared with healthy subjects. The vasodilator capacity to pressure was significantly lower in patients with DFU compared with those without DFU, despite the absence of significant difference in cutaneous pressure perception threshold and vascular reactivity to acetylcholine, sodium nitroprusside, and heat. This pronounced alteration of neurovascular response to pressure in patients with DFU is a good marker of skin vulnerability and could be used to better predict individuals at risk.

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.

The influence of population characteristics and measurement system on barefoot plantar pressures: A systematic review and meta-regression analysis

BACKGROUND

The measurement of plantar pressure distributions during gait can provide insights into the effects of musculoskeletal disease on foot function. A range of hardware, software, and protocols are available for the collection of this type of data, with sometimes disparate and conflicting results reported between individual studies. In this systematic review and meta-regression analysis of dynamic regional peak pressures, we aimed to test if 1) the system used to obtain the pressure measurements and 2) the characteristics of the study populations had a significant effect on the results.

METHODS

A systematic review of the literature was undertaken to identify articles reporting regional peak plantar pressures during barefoot walking. A mixed-effects modeling approach was used to analyze the extracted data. Initially, the effect of the system used to collect the data was tested. Following this, the effect of participant characteristics on the results were analyzed, using moderators of cohort type (defined as the primary health characteristic of the participants), age, sex, and BMI.

RESULTS

115 participant groups were included in the analysis. Sufficient cohorts were available to test those that consisted of healthy individuals, and those with diabetes and diabetic neuropathy. Significant differences were found between results reported by studies using different pressure measurement systems in 8 of the 16 regions analyzed. The analysis of participant characteristics revealed a number of significant relationships between regional peak pressures and participant characteristics, including: BMI and midfoot plantar pressures; elevated forefoot pressures as a result of diabetic neuropathy; and sex-differences in regional loading patterns.

CONCLUSIONS

At the level of the literature, we confirmed significant effects of disease status, age, BMI, and sex on regional peak plantar pressures. Researchers and clinicians should be aware that measurements of peak plantar pressure variables obtained from different collection equipment are not directly comparable.

The development and validation of a multivariable prognostic model to predict foot ulceration in diabetes using a systematic review and individual patient data meta-analyses

AIMS

Diabetes guidelines recommend screening for the risk of foot ulceration but vary substantially in the underlying evidence base. Our purpose was to derive and validate a prognostic model of independent risk factors for foot ulceration in diabetes using all available individual patient data from cohort studies conducted worldwide.

METHODS

We conducted a systematic review and meta-analysis of individual patient data from 10 cohort studies of risk factors in the prediction of foot ulceration in diabetes. Predictors were selected for plausibility, availability and low heterogeneity. Logistic regression produced adjusted odds ratios (ORs) for foot ulceration by ulceration history, monofilament insensitivity, any absent pedal pulse, age, sex and diabetes duration.

RESULTS

The 10 studies contained data from 16 385 participants. A history of foot ulceration produced the largest OR [6.59 (95% CI 2.49 to 17.45)], insensitivity to a 10 g monofilament [3.18 (95% CI 2.65 to 3.82)] and any absent pedal pulse [1.97 (95% CI 1.62 to 2.39)] were consistently, independently predictive. Combining three predictors produced sensitivities between 90.0% (95% CI 69.9% to 97.2%) and 95.3% (95% CI 84.5% to 98.7%); the corresponding specificities were between 12.1% (95% CI 8.2% to 17.3%) and 63.9% (95% CI 61.1% to 66.6%).

CONCLUSIONS

This prognostic model of only three risk factors, a history of foot ulceration, an inability to feel a 10 g monofilament and the absence of any pedal pulse, compares favourably with more complex approaches to foot risk assessment recommended in clinical diabetes guidelines.

Relationship between skin temperature monitoring with Smart Socks and plantar pressure distribution: a pilot study

OBJECTIVE

Increased skin temperature at the plantar aspect of the foot can predict foot ulceration. However its relation to plantar pressure overload is unknown. The aim of this study was to assess the ability of 'smart socks', monitoring plantar temperature under real-life conditions, to predict plantar pressure distribution.

METHOD

The 'smart socks' have seven thermal sensors woven into the fabric of the sock to measure the temperature beneath the foot in real-life conditions. The upper part of the sock is connected to a central unit through which changes in the sensor resistance is converted into temperature changes. Participants were instructed to wear the socks for three continuous hours. Plantar pressure was measured by the MatScan plantar-pressure measurement system (Tekscan Inc., US).

RESULTS

The study included 25 healthy volunteers (11 males, 14 females, mean age was 41.1 years (standard deviation (SD): 17.6) years, a mean body mass index of 29.4 kg/m² (SD: 6.95). Temperature changes at sensor (S) five significantly correlated with metatarsal (M) 2 pressure time integral (PTI) (r=0.519, p=0.008), M3 PTI (r=0.435, p=0.03), M4 PTI (r=0.452, p=0.023). Changes at S5 also significantly correlated with peak pressure at M2 (r=0.66, p=0.000), M3 (r=0.52, p=0.01), and M4 (r=0.60, p=0.002). Temperature changes at S6 were significantly correlated with changes at S1, S2, S3, S4, S5, and S7.

CONCLUSION

Temperature changes at the plantar aspect of the foot measured by the smart socks are correlated with plantar pressure distribution. Furthermore, two sensors at positions S5 and S6 were sufficient to predict plantar pressure changes.

Foot Pressure Changes Before and After Ankle Fusion: A Pedobarograph Study

We performed a case-control study with the purpose of establishing the pressure patterns in the soles of the feet of patients with ankle osteoarthritis, determining whether the pattern changed after treating the arthritis with ankle joint fusion (arthrodesis), and whether the change is significant. We also studied the benefits of ankle fusion with respect to the Short-Form 36-item Health Survey and the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot scale. The study included 18 participants (9 in the study group and 9 in the control group) to reach statistical significance with a 95% confidence interval (CI). A demonstrable increase was found in both forefoot and hind-foot pressures in the study group preoperatively compared with the control group. Also, a demonstrable increase was found in the pressure in both the forefoot (mean difference 50.56 ± 267.39 kPa) and the hindfoot (mean difference 57.44 ± 160.27 kPa) from preoperatively to postoperatively. This difference was not statistically significant (p = .59 [t(8) = 0.57]; 95% CI 256.10 to -154.98) for the forefoot pressures and for the hindfoot pressures (p = .31 [t(8) = 1.08]; 95% CI 180.64 to -65.76). The Short-Form 36-item scores significantly improved from preoperatively to postoperatively (p = .000054 for the physical component and p = .018 for the mental component). The American Orthopaedic Foot and Ankle Society Ankle-Hindfoot scale score also improved significantly (p = .0000005). The foot pressures, as measured by using the insole sensors, showed an increase in forefoot and hindfoot pressures that was not statistically significant.