Intrinsic foot muscle and plantar tissue changes in type 2 diabetes mellitus

From Morphology to Therapeutic Strategies: Exploring New Applications of Ultrasound for Diabetic Peripheral Neuropathy Diagnosis and Management

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes that can result in severe lower limb pain and amputation. Early detection and treatment of DPN are vital, but this condition is often missed due to a lack of symptoms and the insensitivity of testing methods. This article reviews various ultrasound imaging modalities in the direct and indirect evaluation of peripheral neuropathy. Moreover, how ultrasound-related therapeutic strategies are playing a role in clinical treatment is discussed. Finally, the application of innovative methodologies in the diagnosis of DPN, including ultrasound attenuation, photoacoustic imaging, and artificial intelligence, is described.

Imaging of Sarcopenia in Type 2 Diabetes Mellitus

Sarcopenia is an age-related condition characterized by the loss of skeletal muscle mass, muscular strength, and muscle function. In older adults, type 2 diabetes mellitus (T2DM) constitutes a significant health burden. Skeletal muscle damage and deterioration have emerged as novel chronic complications in patients with diabetes, often linked to their increased longevity. Diabetic sarcopenia has been associated with increased rates of hospitalization, cardiovascular events, and mortality. Nevertheless, effectively managing metabolic disorders in patients with T2DM through appropriate therapeutic interventions could potentially mitigate the risk of sarcopenia. Utilizing imaging technologies holds substantial clinical significance in the early detection of skeletal muscle mass alterations associated with sarcopenia. Such detection is pivotal for arresting disease progression and preserving patients' quality of life. These imaging modalities offer reproducible and consistent patterns over time, as they all provide varying degrees of quantitative data. This review primarily delves into the application of dual-energy X-ray absorptiometry, computed tomography, magnetic resonance imaging, and ultrasound for both qualitative and quantitative assessments of muscle mass in patients with T2DM. It also juxtaposes the merits and limitations of these four techniques. By understanding the nuances of each method, clinicians can discern how best to apply them in diverse clinical scenarios.

Sub-calcaneal plantar fat pad assessment using dual-energy computed tomography: First experience in the diabetic foot

BACKGROUND

This study assessed the use of dual-energy computed tomography (CT) to evaluate sub-calcaneal plantar fat pad changes in people with diabetic neuropathy.

METHODS

Dual-energy CT scans of people with diabetic neuropathy and non-diabetic controls were retrospectively included. Average CT values (in Hounsfield Units) and thickness (in centimeters) of the sub-calcaneal plantar fat pad were measured in mono-energetic images at two energy levels (40 keV and 70 keV). The CT values measured in patients with diabetic neuropathy were correlated to barefoot plantar pressure measurements performed during walking in a clinical setting.

FINDINGS

Forty-five dual-energy CT scans of people with diabetic neuropathy and eleven DECT scans of non-diabetic controls were included. Mean sub-calcaneal plantar fat pad thickness did not significantly differ between groups (diabetes group 1.20 ± 0.34 cm vs. control group 1.21 ± 0.28 cm, P = 0.585). CT values at both 40 keV (-34.7 ± 48.7 HU vs. -76.0 ± 42.8 HU, P = 0.013) and 70 keV (-11.2 ± 30.8 HU vs. -36.3 ± 27.2 HU, P = 0.017) were significantly higher in the diabetes group compared to controls, thus contained less fatty tissue. This elevation was most apparent in patients with Type 1 diabetes. CT values positively correlated with the mean peak plantar pressure.

INTERPRETATION

Dual-energy CT was able to detect changes in the plantar fat pad of people with diabetic neuropathy.

Local microvascular tissue oxygenation of the intrinsic foot muscles in patients with diabetes: A cross-sectional case-comparison study

BACKGROUND

Foot-related complications including impaired peripheral circulation and lower limb ulceration are severe consequences for those with diabetes mellitus. This study aimed to assess differences in tissue oxygenation and oxygen utilization of the plantar surface intrinsic foot muscles between diabetic participants and healthy comparisons following short foot exercise and a standard walking protocol.

METHODS

Eighteen participants, 9 with diabetes and 9 healthy age- and sex-matched comparisons, completed two interventions in a randomized order. For the short foot exercise intervention, participants completed 5 sets of 15 intrinsic foot muscle contractions. For the walking intervention, participants completed a modified six-minute walk test. Tissue oxygenation variables including oxygenated hemoglobin, deoxygenated hemoglobin, and tissue saturation index were measured using near-infrared spectroscopy in quiet stance and during intrinsic foot muscle contraction cycles following each intervention. Means, standard deviations, 95 % confidence intervals, mean differences, and Cohen's d effect sizes were calculated for each tissue oxygenation variable.

RESULTS

The results of this study indicated no significant group differences in quiet standing tissue oxygenation measures at baseline and following each intervention. Participants in the diabetic group had significantly less change in tissue saturation index during intrinsic foot muscle contractions compared to healthy participants after the short foot exercise intervention (ES= 4.00, P = .0002) and walking intervention (ES= 1.33, P = .015).

CONCLUSIONS

By utilizing wireless NIRS and novel research methodology, this study was able to explore changes in plantar surface tissue oxygenation of the intrinsic foot muscles following a targeted short foot exercise intervention as well as a standard walking protocol in patients diagnosed with diabetes compared to age- and sex- matched individuals without diabetes. We identified that diabetic participants presented with less oxygen utilization during intrinsic foot muscle contractions performed following both exercise interventions compared to their healthy age- and sex- matched comparisons.

Current evidence regarding 2D ultrasonography monitoring of intrinsic foot muscle properties: A systematic review

Background

Ultrasonography can discriminate between intrinsic and extrinsic foot muscle properties and has therefore gained considerable popularity as an indirect strength evaluation. However, an overview on the use of ultrasound for assessing intrinsic foot musculature (IFM) is currently lacking.

Research question

What is the current evidence regarding (1) 2D ultrasonography protocols and its reliability? (2) Reference values for cross-sectional area and dorso-plantar thickness evaluation in asymptomatic and symptomatic persons?

Methods

The PRISMA guidelines were used to conduct this systematic review. Eight databases (PubMed, Embase, Web of Science, Cochrane Library, Scopus, CINAHL, SPORTDiscus and EuropePMC) were searched up to November 1, 2021. Studies reporting quantitative 2D ultrasound findings of the intrinsic foot muscles with no limitation to sex, BMI, ethnicity or physical activity were included. Studies were assessed for methodological quality using the Downs and Black checklist.

Results

Fifty-three studies were retained. Protocols showed an overall good to great reliability, suggesting limits of agreement between 8 and 30% of relative muscle size with minimal detectable changes varying from 0.10 to 0.29 cm² for cross-sectional area and 0.03-0.23 cm for thickness. Reference values are proposed for both cross-sectional area and thickness measurements of the abductor hallucis, flexor digitorum brevis, flexor hallucis brevis and quadratus plantae in asymptomatic persons. This could not be performed in the symptomatic studies due to a limited number of relevant studies addressing the symptomatic population, therefore a clinical overview is outlined. Clinically, IFM properties have been studied in ten distinct pathological conditions, predominantly pointing towards decreased muscle properties of the abductor hallucis.

Significance

We provide a clear and comprehensive overview of the literature regarding 2D ultrasonography of the IFM, making the available evidence more accessible to decision makers and researchers.

Crural and Plantar Fasciae Changes in Chronic Charcot Diabetic Foot: A Cross-Sectional Ultrasound Imaging Study-An Evidence of Fascial Continuity

Crural fascia (CF) and plantar fascia (PF) are biomechanically crucial in the gait and in the proprioception, particularly in the propulsion phase of the foot during the gait cycle and in the dissipation of forces during weight-bearing activities. Recent studies have revealed an association between increases in PF thickness and diabetes. The purpose of this study was to measure and compare by ultrasound (US) imaging the thickness of the CF and PF at different regions/levels in chronic Charcot diabetic foot patients (group 1) and in healthy volunteers (group 2). A cross-sectional study was performed using US imaging to measure the CF with Pirri et al.'s protocol and PF with a new protocol in a sample of 31 subjects (15 patients and 16 healthy participants). The findings for CF and PF revealed statistically significant differences in the poster region of CF (Post 1: group 1 vs. group 2: p = 0.03; Post 2: group 1 vs. group 2: p = 0.03) and in PF at two different levels (PF level 1: group 1 vs. group 2: p < 0.0001; PF level 2: group 1 vs. group 2: p < 0.0001). These findings suggest that chronic Charcot diabetic foot patients have CF and PF thicker compared to healthy volunteers. The US examination suggests that fascial thicknesses behavior in these patients points out altered fascial remodeling due to diabetes pathology and biomechanical changes.

Diabetes and Its Cardiovascular Complications: Comprehensive Network and Systematic Analyses

Diabetes mellitus is a worldwide health problem that usually comes with severe complications. There is no cure for diabetes yet and the threat of these complications is what keeps researchers investigating mechanisms and treatments for diabetes mellitus. Due to advancements in genomics, epigenomics, proteomics, and single-cell multiomics research, considerable progress has been made toward understanding the mechanisms of diabetes mellitus. In addition, investigation of the association between diabetes and other physiological systems revealed potentially novel pathways and targets involved in the initiation and progress of diabetes. This review focuses on current advancements in studying the mechanisms of diabetes by using genomic, epigenomic, proteomic, and single-cell multiomic analysis methods. It will also focus on recent findings pertaining to the relationship between diabetes and other biological processes, and new findings on the contribution of diabetes to several pathological conditions.

Fat Is Consistently Present within the Plantar Muscular Space of the Human Foot—An Anatomical Study

Background and Objectives: The foot comprises of active contractile and passive connective tissue components, which help maintain stability and facilitate movement during gait. The role of age- or pathology-related degeneration and the presence of fat within muscles in foot function and pain remains unclear. The existence of fat has to date not been quantified or compared between individuals according to age, sex, side or subregion. Materials and Methods: 18 cadaveric feet (mean age 79 years) were sectioned sagittally and photographed bilaterally. Fat in the plantar muscular space of the foot (PMSF) was quantified through the previously validated manual fat quantification method, which involved observing photographs of each section and identifying regions using OsiriX. Fat volume and percentage was calculated using a modified Cavalieri’s method. Results: All feet had fat located within the PMSF, averaging 25.8% (range, 16.5–39.4%) of the total PMSF volume. The presence of fat was further confirmed with plastination and confocal microscopy. Conclusions: These findings suggest that fat within the PMSF is a consistent but highly variable finding in elderly cohorts. Fat within the foot muscles may need to be considered a norm when comparing healthy and non-healthy subjects, and for therapeutic interventions to the foot. Further work is required to understand in detail the morphological and mechanical presence of fat in the foot, and compare these findings with pathological cohorts, such as sarcopenia. Additionally, future work should investigate if fat may compensate for the degeneration of the intrinsic muscles of the foot, with implications for both the use of orthotics and pain management.

Irregularity in Plantar Fascia, Muscle Edema and Tendon Thickness in Patients with High-Risk for Diabetic Foot

AIM

To investigate the alterations in the plantar fascia (PF), intrinsic muscles, and tendons in the feet of patients at high risk for developing diabetic foot.

METHODS

The healthy feet of 22 patients with type 2 diabetes, who had developed diabetic foot ulcers on a single foot without any pathology on the contralateral extremity, and those of 22 healthy volunteers were evaluated by magnetic resonance imaging. The volume of the Achilles tendon (AT), the surface area of the PF, the thickness of AT, flexor hallucis longus, flexor digitorum longus, tibialis posterior, and peroneus longus tendons, irregularity in the PF, and edema of intrinsic foot muscles were examined.

RESULTS

Nineteen patients (86%) had irregularity in the PF, whereas none of the healthy controls had any (p<0.001). Intrinsic muscle edema was more common in the group with diabetes (p=0.006). The volume of AT and the surface area of PF were decreased in patients with peripheral arterial disease (PAD) (p<0.05). Patients with diabetes mellitus but without PAD had a larger surface area of PF than that of controls (p<0.05). There were no differences in the volume of AT, the surface area of the PF, and other tendon thickness between the groups.

CONCLUSION

Irregularity in the PF and muscle edema may indicate a high risk for the diabetic foot. The presence of PAD may lead to regression in the structure of AT and PF.

Reliability of ultrasound in evaluating the plantar skin and fat pad of the foot in the setting of diabetes

Ultrasound can be used to assess injury and structural changes to the soft-tissue structure of the foot. It may be useful to assess the feet of people with diabetes who are at increased risk of plantar soft-tissue pathological changes. The aim of this study was to determine if ultrasound measurements of plantar soft-tissue thickness and assessments of tissue acoustic characteristics are reliable in people with and without diabetes mellitus. A repeated measures design was used to determine intra-observer reliability for ultrasound measurements of plantar skin and fat pad thickness and intra- and inter-observer reliability of plantar skin and fat pad tissue characterisation assessments made at foot sites which are at risk of tissue injury in people with diabetes. Thickness measurements and tissue characterisation assessments were obtained at the heel and forefoot in both the unloaded and compressed states and included discrete layers of the plantar tissues: skin, microchamber, horizontal fibrous band, macrochamber and total soft-tissue depth. At each site, relative intra-observer reliability was achieved for the measurement of at least one plantar tissue layer. The total soft-tissue thickness measured in the unloaded state (ICC 0.925-0.976) demonstrated intra-observer reliability and is the most sensitive for detecting small change on repeated measures. Intra-observer agreement was demonstrated for tissue characteristic assessments of the skin at the heel (k = 0.70), fat pad at the lateral sesamoid region (k = 0.70) and both skin and fat pad at the second (k = 0.80, k = 0.70 respectively) and third metatarsal heads (k = 0.90, k = 0.79 respectively). However, acceptable inter-observer agreement was not demonstrated for any tissue characteristic assessment, therefore the use of multiple observers should be avoided when making these assessments.

Diabetic Foot: The Role of Fasciae, a Narrative Review

Simple Summary

Diabetes mellitus and its complications are increasingly prevalent worldwide with severe impacts on patients and health care systems. Diabetic foot ulcers have an important impact on disability, morbidity, and mortality. The mechanism of diabetic wound chronicity has not yet been understood in a complete way. Regarding the involved soft tissues, little space has been given to the fasciae, even if nowadays there is more and more evidence of their role in proprioception, muscular force transmission, skin vascularization and tropism, and wound healing. Thus, we aimed to deepen the fascial involvement in diabetic wounds. Based on this review, we suggest that a clear scientific perception of fascial role can improve treatment strategies and create new perspectives of treatment.

Abstract

Wound healing is an intricate, dynamic process, in which various elements such as hyperglycemia, neuropathy, blood supply, matrix turnover, wound contraction, and the microbiome all have a role in this “out of tune” diabetic complex symphony, particularly noticeable in the complications of diabetic foot. Recently it was demonstrated that the fasciae have a crucial role in proprioception, muscular force transmission, skin vascularization and tropism, and wound healing. Indeed, the fasciae are a dynamic multifaceted meshwork of connective tissue comprised of diverse cells settled down in the extracellular matrix and nervous fibers; each constituent plays a particular role in the fasciae adapting in various ways to the diverse stimuli. This review intends to deepen the discussion on the possible fascial role in diabetic wounds. In diabetes, the thickening of collagen, the fragmentation of elastic fibers, and the changes in glycosaminoglycans, in particular hyaluronan, leads to changes in the stiffness, gliding, and the distribution of force transmission in the fasciae, with cascading repercussions at the cellular and molecular levels, consequently feeding a vicious pathophysiological circle. A clear scientific perception of fascial role from microscopic and macroscopic points of view can facilitate the identification of appropriate treatment strategies for wounds in diabetes and create new perspectives of treatment.

Simple model of arch support: Relevance to Charcot Neuroarthropathy

BACKGROUND

Charcot neuropathy is a common complication resulting from poorly controlled diabetes and peripheral neuropathy leading to the collapse, and ultimately the breakdown, of the midfoot. Mechanically, it is likely that a compromised arch support in this, or any other patient group that experiences foot flattening, would be associated with slippage at the distal and proximal interface regions of the plantar surface of the foot and the adjacent support surface. This slippage, although difficult to quantify with standard motion capture systems used in a gait laboratory, could potentially be assessed with systems for monitoring interface shear stresses. However, before investing in such systems, a correlation between arch flattening and interface shear stresses needs to be verified.

METHODS

For this purpose, a sagittal plane model of a foot was developed using a multi-body dynamics package (MSC Adams). This model mimicked a subject swaying back and forth, and was constructed to show the dependence of interface stresses on altered arch support.

FINDINGS

The model's predictions matched typical FootSTEPS data: lengthening of the arch of 1-2 mm, sway oscillations of 0.22-0.33 s and frictional force differences (calcaneus relative to forefoot) of 60 N. Of clinical relevance, when the stiffness of the plantar spring (representing aponeurosis and intrinsic muscles) was reduced by 10%, the frictional force difference increased by about 6.5%.

INTERPRETATION

The clinical implications of this study are that, while arch lengthening of less than 2 mm might be difficult to measure reliably in a gait lab, using shear sensors under the forefoot and hindfoot should allow arch support to be assessed in a repeatable manner.

Plantar soft tissues and Achilles tendon thickness and stiffness in people with diabetes: a systematic review

BACKGROUND

Diabetes mellitus is associated with changes in soft tissue structure and function. However, the directionality of this change and the extent to which either tissue thickness or stiffness contributes to the pathogenesis of diabetes-related foot ulcerations is unclear. Hence, this systematic review aims to summarise the existing evidence for soft tissue structural differences in the feet of people with and without diabetes.

METHODS

In compliance with MOOSE and PRISMA guidelines, AMED, CINAHL, MEDLINE, ProQuest Health & Medical Collection, ProQuest Nursing & Allied Health Database, and Web of Science electronic databases were systematically searched for studies published from database inception until 1st October 2020 [Prospero CRD42020166614]. Reference lists of included studies were further screened. Methodological quality was appraised using a modified critical appraisal tool for quantitative studies developed by McMaster University.

RESULTS

A total of 35 non-randomised observational studies were suitable for inclusion. Within these, 20 studies evaluated plantar tissue thickness, 19 studies evaluated plantar tissue stiffness, 9 studies evaluated Achilles tendon thickness and 5 studies evaluated Achilles tendon stiffness outcomes. No significant differences in plantar tissue thickness were found between people with and without diabetes in 55% of studies (11/20), while significantly increased plantar tissue stiffness was found in people with diabetes in 47% of studies (9/19). Significantly increased Achilles tendon thickness was found in people with diabetes in 44% of studies (4/9), while no significant differences in Achilles tendon stiffness were found between people with and without diabetes in 60% of studies (3/5).

CONCLUSIONS

This systematic review found some evidence of soft tissue structural differences between people with and without diabetes. However, uncertainty remains whether these differences independently contribute to diabetes-related foot ulcerations. The heterogeneity of methodological approaches made it difficult to compare across studies and methodological quality was generally inadequate. High-quality studies using standardised and validated assessment techniques in well-defined populations are required to determine more fully the role of structural tissue properties in the pathogenesis of diabetes-related foot ulcerations.

Using Bidimensional Multiscale Entropy Analysis of Ultrasound Images to Assess the Effect of Various Walking Intensities on Plantar Soft Tissues

Walking performance is usually assessed by linear analysis of walking outcome measures. However, human movements consist of both linear and nonlinear complexity components. The purpose of this study was to use bidimensional multiscale entropy analysis of ultrasound images to evaluate the effects of various walking intensities on plantar soft tissues. Twelve participants were recruited to perform six walking protocols, consisting of three speeds (slow at 1.8 mph, moderate at 3.6 mph, and fast at 5.4 mph) for two durations (10 and 20 min). A B-mode ultrasound was used to assess plantar soft tissues before and after six walking protocols. Bidimensional multiscale entropy (MSE_2D) and the Complexity Index (CI) were used to quantify the changes in irregularity of the ultrasound images of the plantar soft tissues. The results showed that the CI of ultrasound images after 20 min walking increased when compared to before walking (CI₄: 0.39 vs. 0.35; CI₅: 0.48 vs. 0.43, p < 0.05). When comparing 20 and 10 min walking protocols at 3.6 mph, the CI was higher after 20 min walking than after 10 min walking (CI₄: 0.39 vs. 0.36, p < 0.05; and CI₅: 0.48 vs. 0.44, p < 0.05). This is the first study to use bidimensional multiscale entropy analysis of ultrasound images to assess plantar soft tissues after various walking intensities.

Ultrasound in the Modern Management of the Diabetic Foot Syndrome: A Multipurpose Versatile Toolkit

Ultrasound (US) is a noninvasive and versatile technology that in recent years found acceptance in almost all the medical specialties, with diagnostic and interventional applications. In the diabetic foot syndrome (DFS), US found specific indications mainly in the screening, quantification, and follow-up of the vascular component of the pathology, but also in the study of the deformities and structural modifications induced by neuropathy and in the diagnosis and surgical management of infections, especially those that induce anatomical changes, like abscesses and fasciitis. This review will summarize all these application of US, giving special attention to the vascular aspects, and on the predominant role that US gained in recent times to guide the indication to revascularization, on the new standardized approach to the study of the arterial tree of the limb and the foot, the so-called duplex ultrasound arterial mapping, which significantly increased the utilization of US to plan the revascularizations in this complex pathology. Outside the vascular fields, the diagnosis of neuropathy and infection and the intraoperative use of US in the surgical management of abscesses and fasciitis will be discussed, leaving the last part to the new and interesting applications of US in the management of DFU, a field that is still in evolution, offering new possibilities to the health care professionals involved in the management of these chronic wounds. The variety of applications both in diagnostic and operative fields makes US a rather versatile technology-a toolkit-that should have a special place among those at reach of the specialists of DFS care.

Differences in the Sub-Metatarsal Fat Pad Atrophy Symptoms between Patients with Metatarsal Head Resection and Those without Metatarsal Head Resection: A Cross-Sectional Study

We aimed to evaluate the differences in the sub-metatarsal skin and fat pad atrophy between patients at a high risk of ulceration with and without previous metatarsal head resection. A cross-sectional study was performed in a diabetic foot unit involving 19 participants with a history of metatarsal head resection (experimental group) and 19 (control group) without a history of metatarsal head resection but with an ulcer in other locations in the metatarsal head. No participants had active ulcerations at study inclusion. Sub-metatarsal skin thickness and fat pad thickness in the first and second metatarsals were evaluated by an ultrasound transducer. The experimental group showed sub-metatarsal fat pad atrophy (3.74 ± 1.18 mm and 2.52 ± 1.04 mm for first and second metatarsal, respectively) compared with the control group (5.44 ± 1.12 mm and 4.73 ± 1.59 mm) (p < 0.001, confidence interval: (CI): 0.943-2.457 and p < 0.001, CI: 1.143-3.270 for first and second metatarsal, respectively); however, sub-metatarsal skin thickness was not different between groups (experimental 2.47 ± 0.47 mm vs. control 2.80 ± 0.58 mm (p = 0.063, CI: -0.019-0.672) and 2.24 ± 0.60 mm vs. 2.62 ± 0.50 mm (p = 0.066, CI: -0.027-0.786) for first and second metatarsal, respectively). Patients with previous metatarsal head resection showed sub-metatarsal fat pad atrophy, which could be associated with the risk of reulceration in the metatarsal head.

Using Skin Bioengineering to Highlight How Weight and Diabetes Mellitus Modify the Skin in the Lower Limbs of Super-Obese Patients

AIM

To evaluate the distinct contribution of obesity and diabetes (DM) to the skin modification in metabolic diseases.

METHODS

We analysed all patients admitted for bariatric surgery in our hospital with BMI between 38 and 47 kg/m², with (Group 1) or without (Group 2) DM and compared them with a group of nonobese diabetic patients (Group 3) and healthy volunteers (Group 4). The following features were evaluated: hardness, temperature, hydration and thickness alongside with anthropometric measures of foot and leg.

RESULTS

For the general characteristics, patients differed in age and body mass index. As predictable all circumferences (dorsal foot, sovramalleolar and under the knee) were significantly higher in obese with no differences depending on DM (all parameters: p<0.01 in Group 1 and Group 2 vs Group 3 and Group 4). Skin temperature was significantly higher in all obese, irrespectively from the presence of DM (1st metatarsal head: p=0.02 Group 1 and Group 2 vs Group 3 and Group 4; 5th metatarsal head: p<0.01 in Group 1 and Group 2 vs Group 3 and Group 4). Skin hydration score showed increased anhydrosis in both diabetics and severe obesity (p<0.01 in Group 1 and Group 3 vs Group 2 and Group 4). Increase in thickness of skin and subcutaneous tissues was observed (at heel: p<0.01 in Group 1 and Group 2 vs Group 3 and Group 4 and under the scaphoid p=0.03 Group 1 and Group 2 vs Group 3 and Group 4) and plantar fascia (in both regions p=0.02 Group 1 and Group 2 vs Group 3 and Group 4) in all obese patients, with or without DM.

CONCLUSION

Severe obesity significantly affects both shape and structure of the foot, possibly exposing these patients to a higher risk of biomechanical stress. On such a background DM, modifying skin hydration and protective mechanisms exerts a synergistic role further increasing the risk of trauma and ulcers.

Prediction of peak plantar pressure for diabetic foot: The regressional model

BACKGROUND

The increase in peak plantar pressure could be the most important etiological factor for pathogenesis of a diabetic foot. Thus the fate of a diabetic foot syndrome which is a clinical triad of neurological, vascular and musculoskeletal changes could be biomechanically predictive and preventive using clinical parameters. In the presence of peripheral neuropathy, certain clinical parameters could be severely altered resulting into increased peak plantar pressure. Therefore the aim of the study was to identify the most important clinical parameters for the prediction of peak plantar pressure between neuropathy and non-neuropathy type 2 diabetes mellitus participants.

METHODOLOGY

A total of 380 participants were recruited under the study and divided into two groups (190 each group). The cross-sectional study was conducted at Kasturba Hosipal, Manipal, India. Multiple regression analysis was performed to find the hyperplane of best fit. Stepwise regression was performed with (α entry=0.15 and α removal=0.2) to select the best subset of predictors.

RESULTS

Adjusted R2 of the final model which included the predictors showed 90.8% variability for the dependent variable.

CONCLUSION

The findings from the regression analysis suggested model was found to be strongly significant in predicting the peak plantar pressure between neuropathy and non-neuropathy type 2 diabetes mellitus participants. Since higher values of peak plantar pressure is strongly associated with risk for future diabetic foot complications, it could be suggested that these clinical parameters could be very useful to assess and should be used in routine clinical practice very effectively.

Can ultrasound measures of intrinsic foot muscles and plantar soft tissues predict future diabetes-related foot disease? A systematic review

Introduction

Diabetes mellitus (DM) is associated with hyperglycaemia and advanced glycosylation end-products. In the foot, the consequences of chronic or uncontrolled diabetes are micro and macrovascular disease, neuropathy, reduced joint mobility and structural and soft tissue changes that increase the risk of ulcer development and amputation. Diabetes foot assessment currently includes a comprehensive history, neurological and vascular assessments and examination focussed on dermatological and musculoskeletal abnormalities. Whilst these assessments are helpful for predicting ulceration risk, direct identifiers that enable early therapeutic intervention are lacking. The intention of this review was to ascertain if B-mode ultrasound could be clinically applied to identify structural change in the diabetic foot and be utilised as an early predictor of ulceration risk.

Methods

Primary databases and grey literature sources were systematically searched. Selection criteria were that the study included a diabetic sample and used B-mode ultrasound to assess soft tissue structures of the foot (plantar skin, plantar fat pad or intrinsic muscles).

Results

Fifteen studies were identified for inclusion (combined diabetic sample of 773). Ultrasound demonstrated reductions in tissue thickness in diabetics compared to non-diabetics under first (p = 0.01) and second (p = 0.03) metatarsal heads, but not the third (p = 0.24). Statistical heterogeneity was high for ultrasound thickness measures under metatarsal heads four/five (I² 65%, 81%) and very high for plantar skin (I² 98%), heel pad (I² 76%) and intrinsic muscles (I² 91%, 81%). Extensor digitorum brevis (EDB) ultrasound measures were significantly thinner in diabetics for all dimension measures compared to healthy controls except one study, which reported no significant differences in EDB thickness.

Conclusions

No direct evidence was found to indicate B-mode ultrasound measures can predict soft tissue changes in the plantar foot in diabetes, although low level studies indicate ultrasound has the potential to identify structural change. Clinical, methodological and statistical heterogeneity limit result applicability. This review highlights the need for robust prospective longitudinal research to examine the predictive validity of this method.

Plantar fascia enthesopathy is highly prevalent in diabetic patients without peripheral neuropathy and correlates with retinopathy and impaired kidney function

BACKGROUND

Aim of this study was to evaluate the prevalence of plantar fascia (PF) enthesopathy in Type 2 diabetes mellitus (T2DM) patients without distal peripheral neuropathy (DPN).

METHODS

We recruited 50 T2DM patients without DPN and 50 healthy controls. DPN was excluded using the Michigan Neuropathy Screening Instrument (MNSI). All patients underwent a bilateral sonographicevaluation of the enthesealportion of the PF.

RESULTS

PF thickness was significantly higher in T2DM patients (p<0.0001). T2DM patients presented a higher prevalence of entheseal thickening (p = 0.002), enthesophyte (p = 0.02) and cortical irregularity (p = 0.02). The overall sum of abnormalities was higher in T2DM patients (p<0.0001), as was the percentage of bilateral involvement (p = 0.005). In a logistic regression analysis, retinopathy predicted entheseal thickening (OR 3.5, p = 0.05) and enthesophytes (OR 5.13, p = 0.001); reduced eGFR predicted enthesophytes (OR 2.93, p = 0.04); body mass index (BMI) predicted cortical irregularity (OR 0.87, p = 0.05); mean glucose predicted enthesophyte (OR 1.01, p = 0.03); LDL cholesterol predicted cortical irregularity (OR 0.98, p = 0.02).

CONCLUSIONS

Our data suggest that T2DM is associated with PF enthesopathyindependently of DPN.

Kinetics and kinematics of diabetic foot in type 2 diabetes mellitus with and without peripheral neuropathy: a systematic review and meta-analysis

Background

Diabetes mellitus patients are at increased risk of developing diabetic foot with peripheral neuropathy, vascular and musculoskeletal complications. Therefore they are prone to develop frequent and often foot problems with a relative high risk of infection, gangrene and amputation. In addition, altered plantar pressure distribution is an important etiopathogenic risk factor for the development of foot ulcers. Thus the review on study of foot kinematic and kinetic in type 2 diabetes mellitus to understand the biomechanical changes is important.

Methodology

Scientific articles were obtained using electronic databases including Science Direct, CINAHL, Springer Link, Medline, Web of Science, and Pubmed. The selection was completed after reading the full texts. Studies using experimental design with focus on biomechanics of diabetic foot were selected.

Results

The meta-analysis report on gait velocity (neuropathy = 128 and non-diabetes = 131) showed that there was a significantly lower gait velocity in neuropathy participants compared to non-diabetes age matched participants at a high effect level (−0.09, 95 % CI −0.13 to 0.05; p < 0.0001). Regarding knee joint flexion range there was a significant difference between neuropathy and non-diabetes group (4.75, 95 % CI, −7.53 to 1.97, p = 0.0008).

Conclusions

The systematic review with meta-analysis reported significant difference in kinematic and kinetic variables among diabetic with neuropathy, diabetic without neuropathy and non-diabetes individuals. The review also found that the sample size in some studies were not statistically significant to perform the meta-analysis and report a strong conclusion. Therefore a study with higher sample size should be done.

Detecting intrinsic muscle weakness of the hallux as an addition to early-stage screening of the feet in patients with diabetes

AIMS

Present-day screening of the diabetic foot involves the Semmes Weinstein Monofilament Test for evaluating loss of sensibility, while testing for intrinsic muscle weakness is not implied. Just as with the early detection of sensibility loss, early detection of intrinsic muscle weakness might have important implications for the prevention of both ulceration and deformity in patients with diabetes. The purpose of this study is to investigate the prevalence of patients with diabetes presenting intrinsic muscle weakness of the hallux, but with a normal sensibility of the sole of the foot.

METHODS

A cross-sectional study design was applied. Intrinsic muscle function of the hallux was measured with the Paper Grip Test, while sensibility of the sole of the foot was measured with the Semmes Weinstein Monofilament Test 5.07/10-g.

RESULTS

In a period of three months a total of 266 patients with diabetes (mean age 60, 134 females (50%), 177 type 2 diabetes mellitus (67%)) met the inclusion criteria and were examined for both intrinsic muscle weakness of the hallux and sensibility of the soles of the feet. The results showed that intrinsic muscle weakness was present more frequent in patients with impaired sensibility (P=0.001), also 20% of the population had intrinsic muscle weakness in the presence of normal sensibility. Multivariate regression analysis showed that only age is associated with patients with diabetes presenting normal sensibility but impaired intrinsic muscle function (P=0.017).

CONCLUSIONS

The Paper Grip Test could have added value to current physical examination of the feet in patients with diabetes.