The effect of the boron-based gel on the treatment of diabetic foot ulcers: A prospective,randomized controlled trial

BackgroundChronic ulcers represent impaired healing capacity with high mortality in the elderly or patients with systemic disorders such as diabetes. Boron is an effective agent in wound healing by promoting cell migration and proliferation and reducing inflammation in the wound area. This study aimed to evaluate the therapeutic effect of a sodium pentaborate-based topical formulation compared to control on the treatment of diabetic foot ulcers.MethodsA prospective, double-blind, randomized controlled trial was conducted to apply randomly the topical sodium pentaborate 3% gel or topical conventional remedy (control) by patients diagnosed with diabetic foot ulcers. The 171 eligible participants aged 18–75 years received the allocated medicines twice a day for a month with an allocation ratio of 3:1. Twenty-five days and two months after the end of the trial, participants were reinvestigated for their ulcer condition and any recurrence. Wagner’s classification of diabetic foot ulcers was applied to this purpose (0−5).Results161 participants (57 females, 104 males; mean age: 59.37) completed this study. After the intervention, most participants in the intervention group had a lower ulcer grade than the control group (adjusted mean difference (95% CI): − 0.91 (−1.1 to −0.73); p < 0.001). Moreover, most participants in the intervention group (n = 109 (90.8%)) were treated at a higher rate than the control group (n = 5 (12.2%)) after intervention (adjusted odds ratio (95% CI): 0.008 (0.002–0.029); p < 0.001). There was no case of recurrence in the intervention group while its rate was (n = 2 (40%)) in the control group (p < 0.001).ConclusionThe present study suggests that topical sodium pentaborate gel may help treat and decrease the grade of diabetic foot ulcers and prevent the recurrence of diabetic foot ulcers.     

Metformin Induces Cell Cycle Arrest,Reduced Proliferation,Wound Healing Impairment In Vivo and Is Associated to Clinical Outcomes in Diabetic Foot Ulcer Patients

BackgroundSeveral epidemiological studies in diabetic patients have demonstrated a protective effect of metformin to the development of several types of cancer. The underlying mechanisms of such phenomenon is related to the effect of metformin on cell proliferation among which, mTOR, AMPK and other targets have been identified. However, little is known about the role that metformin treatment have on other cell types such as keratinocytes and whether exposure to metformin of these cells might have serious repercussions in wound healing delay and in the development of complications in diabetic patients with foot ulcers or in their exacerbation.ResultsMetformin treatment significantly reduces cell proliferation; colony formation and alterations of the cell cycle are observed also in the metformin treated cells, particularly in the S phase. There is a significant increase in the area of the wound of the metformin treated animals at different time points (P<0.05). There is also a significant increase in the size and wound area of the patients with diabetic foot ulcers at the time of hospitalization. A protective effect of metformin was observed for amputation, probably associated with the anti inflammatory effects reported of metformin.ConclusionsMetformin treatment reduces cell proliferation and reduces wound healing in an animal model and affects clinical outcomes in diabetic foot ulcer patients. Chronic use of this drug should be further investigated to provide evidence of their security in association with DFU.     

Prospective cohort study of routine use of risk assessment scales for prediction of pressure ulcers

ObjectiveTo evaluate whether risk assessment scales can be used to identify patients who are likely to get pressure ulcers.DesignProspective cohort study.SettingTwo large hospitals in the Netherlands.Participants1229 patients admitted to the surgical, internal, neurological, or geriatric wards between January 1999 and June 2000.Results135 patients developed pressure ulcers during four weeks after admission. The weekly incidence of patients with pressure ulcers was 6.2% (95% confidence interval 5.2% to 7.2%). The area under the receiver operating characteristic curve was 0.56 (0.51 to 0.61) for the Norton scale, 0.55 (0.49 to 0.60) for the Braden scale, and 0.61 (0.56 to 0.66) for the Waterlow scale; the areas for the subpopulation, excluding patients who received preventive measures without developing pressure ulcers and excluding surgical patients, were 0.71 (0.65 to 0.77), 0.71 (0.64 to 0.78), and 0.68 (0.61 to 0.74), respectively. In this subpopulation, using the recommended cut-off points, the positive predictive value was 7.0% for the Norton, 7.8% for the Braden, and 5.3% for the Waterlow scale.ConclusionAlthough risk assessment scales predict the occurrence of pressure ulcers to some extent, routine use of these scales leads to inefficient use of preventive measures. An accurate risk assessment scale based on prospectively gathered data should be developed.

What is already known on this topic

The incidence of pressure ulcers in hospitalised patients varies between 2.7% and 29.5%Guidelines for prevention of pressure ulcers base the allocation of labour and resource intensive measures on the outcome of risk assessment scalesMost risk assessment scales are based on expert opinion or literature review and have not been evaluatedThe sensitivity and specificity of risk assessment scales vary

What this study adds

The effectiveness of available risk assessment scales is limitedUse of the outcome of risk assessment scales leads to inefficient allocation of preventive measures     

An MRI-compatible foot-loading device for assessment of internal tissue deformation

It is well known that mechanical forces acting within the soft tissues of the foot can contribute to the formation of neuropathic ulcers in people with diabetes. Presently, only surface measurements of plantar pressure are used clinically to estimate risk status due to mechanical loading. It is currently not known how surface measurements relate to the three-dimensional (3-D) internal stress/strain state of the foot. This article describes the development of a foot-loading device that allows for the direct observation of the internal deformation of foot tissues under known forces. Ground reaction forces and plantar pressure distributions during normal walking were measured in ten healthy young adults. One instant in the gait cycle, when pressure under the metatarsal heads reached a peak, was extracted for simulation in an MR imager. T1-weighted 3-D gradient echo MRI sets were collected as the simulated walking ground reaction force was incrementally applied to the foot by the novel foot-loading device. The sub-metatarsal head soft-tissue thickness decreased rapidly at first and then reached a plateau. Peak plantar pressure measurements collected within the loading device (161+/-75kPa) were lower in magnitude and less focal than pressures measured during walking (492+/-91kPa). This finding implies that although the device successfully applied full peak walking ground reaction forces to the foot, they were not distributed in the same manner as during walking. Although not representative of gait, the data collected from this in vivo mechanical test are suitable for determination of foot tissue material properties or, when combined with finite element modeling, to examine the relationship between surface loading and internal stress.     

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

Background

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

Methods

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

Results

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

Conclusions

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

     

Is obesity a risk factor for deep tissue injury in patients with spinal cord injury?

Deep tissue injury (DTI) is a severe form of pressure ulcers that occur in subcutaneous tissue under intact skin by the prolonged compression of soft tissues overlying bony prominences. Pressure ulcers and DTI in particular are common in patients with impaired motosensory capacities, such as those with a spinal cord injury (SCI). Obesity is also common among subjects with SCI, yet there are contradicting indications regarding its potential influence as a risk factor for DTI in conditions where these patients sit in a wheelchair without changing posture for prolonged times. It has been argued that high body mass may lead to a greater risk for DTI due to increase in compressive forces from the bones on overlying deep soft tissues, whereas conversely, it has been argued that the extra body fat associated with obesity may reduce the risk by providing enhanced subcutaneous cushioning that redistributes high interface pressures. No biomechanical evaluation of this situation has been reported to date. In order to elucidate whether obesity can be considered a risk factor for DTI, we developed computational finite element (FE) models of the seated buttocks with 4° of obesity, quantified by body mass index (BMI) values of 25.5, 30, 35 and 40 kg/m². We found that peak principal strains, strain energy densities (SED) and von Mises stresses in internal soft tissues (muscle, fat) overlying the ischial tuberosities (ITs) all increased with BMI. With a rise in BMI from 25.5 to 40 kg/m², values of these parameters increased 1.5 times on average. Moreover, the FE simulations indicated that the bodyweight load transferred through the ITs has a greater effect in increasing internal tissue strains/stresses than the counteracting effect of thickening of the adipose layer which is concurrently associated with obesity. We saw that inducing some muscle atrophy (30% reduction in muscle volume, applied to the BMI=40 kg/m² model) which is also characteristic of chronic SCI resulted in further substantial increase in all biomechanical measures reflecting geometrical distortion of muscle tissue, that is, SED, tensile stress, shear stress and von Mises stress. This result highlights that obesity and muscle atrophy, which are both typical of the chronic phase of SCI, contribute together to the state of elevated tissue loads, which consequently increases the likelihood of DTI in this population.     

Exposure to internal muscle tissue loads under the ischial tuberosities during sitting is elevated at abnormally high or low body mass indices

Deep tissue injury (DTI) is a severe pressure ulcer characteristic of chairfast or bedfast individuals, such as those with impaired mobility or neurological disorders. A DTI differs from superficial pressure ulcers in that the onset of DTI occurs under intact skin, in skeletal muscle tissue overlying bony prominences, and progression of the wound continues subcutaneously until skin breakdown. Due to the nature of this silently progressing wound, it is highly important to screen potentially susceptible individuals for their risk of developing a DTI. Abnormally low and high values of the body mass index (BMI) have been proposed to be associated with pressure ulcers, but a clear mechanism is lacking. We hypothesize that during sitting, exposure to internal muscle tissue loads under the ischial tuberosities (IT) is elevated at abnormally high or low body mass indices. Our aims in this study were: (a) to develop biomechanical models of the IT region in the buttocks that represent an individual who is gaining or losing weight drastically. (b) To determine changes in internal tissue load measures: principal compression strain, strain energy density (SED), principal compression stress and von Mises stress versus the BMI. (c) To determine percentage volumes of muscle tissue exposed to critical levels of the above load measures, which were defined based on our previous animal and tissue engineered model experiments: strain≥50%, stress≥2 kPa, SED≥0.5 kPa. A set of 21 finite element models, which represented the same individual, but with different BMI values within the normal range, above it and below it, was solved for the outcome measures listed above. The models had the same IT shape, size, distance between the IT, and (non-linear) mechanical properties for all soft tissues, but different thicknesses of gluteus muscles and fat tissue layers, corresponding to the BMI level. The resulted data indicated a trend of progressive increase in internal tissue loading, particularly in volumetric exposure to critical loading for BMI values outside the 17≤BMI≤22 kg/m² range, supporting our hypothesis for this study. We concluded that exposure to internal muscle tissue loads under the IT during sitting is optimally reduced at the low-normal BMI range, which is important not only in the context of DTI research, but also for understanding general sitting biomechanics.     

Early Detection of Pressure Ulcers: Considering the Reperfusion

ObjectivesPressure ulcers are a great handicap for those who develop one. Pressure ulcers can take a long time to heal especially if detected late. These afflictions require a lot of time from the medical personnel and thus a great amount of money. We aim here to check the impact of continuous measurement on the performance of early pressure ulcer detection algorithms.Material and methodsTo detect pressure ulcers early on we use a simulation of a human buttocks to simulate the reaction of it to pressure. This simulation considers the most recent findings about pressure ulcers. In particular, the phenomenon of muscle stiffening when pressure is applied for a long period of time, and the reperfusion phenomenon. We can then simulate pressure captors on the outside interface of the buttocks to use these measurements for detection. We then determine the best threshold on the measured pressures to create standard algorithms that we compare to novel algorithms using an optimized threshold on a calculated damage based on the pressure measurement of the last 2 hours.ResultsWe compare these different algorithms for the early detection of pressure ulcers and show the need to take the measurement variation in time for a better detection. The detection error is improved by 7.3% for balanced classes and 2.7% for a dataset with a majority of healthy buttocks.ConclusionWe showed that taking the evolution of pressure instead of only instantaneous measurement can improve the early detection of pressure ulcer.     

Temperature as a predictive tool for plantar triaxial loading

Diabetic foot ulcers are caused by moderate repetitive plantar stresses in the presence of peripheral neuropathy. In severe cases, the development of these foot ulcers can lead to lower extremity amputations. Plantar pressure measurements have been considered a capable predictor of ulceration sites in the past, but some investigations have pointed out inconsistencies when solely relying on this method. The other component of ground reaction forces/stresses, shear, has been understudied due to a lack of adequate equipment. Recent articles reported the potential clinical significance of shear in diabetic ulcer etiology. With the lack of adequate tools, plantar temperature has been used as an alternative method for determining plantar triaxial loading and/or shear. However, this method has not been previously validated. The purpose of this study was to analyze the potential association between exercise-induced plantar temperature increase and plantar stresses. Thirteen healthy individuals walked on a treadmill for 10 minutes at 3.2 km/h. Pre and post-exercise temperature profiles were obtained with a thermal camera. Plantar triaxial stresses were quantified with a custom-built stress plate. A statistically significant correlation was observed between peak shear stress (PSS) and temperature increase (r=0.78), but not between peak resultant stress (PRS) and temperature increase (r=0.46). Plantar temperature increase could predict the location of PSS and PRS in 23% and 39% of the subjects, respectively. Only a moderate linear relationship was established between triaxial plantar stresses and walking-induced temperature increase. Future research will investigate the value of nonlinear models in predicting plantar loading through foot temperature.     

Finite Element Analysis of Foot and Ankle Impact Injury: Risk Evaluation of Calcaneus and Talus Fracture

IntroductionFoot and ankle impact injury is common in geriatric trauma and often leads to fracture of rearfoot, including calcaneus and talus. The objective of this study was to assess the influence of foot impact on the risk of calcaneus and talus fracture via finite element analysis.MethodsA three-dimensional finite element model of foot and ankle was constructed based on magnetic resonance images of a female aged 28. The foot sustained a 7-kg passive impact through a foot plate. The simulated impact velocities were from 2.0 to 7.0 m/s with 1.0 m/s interval.ResultsAt 5.0 m/s impact velocity, the maximum von Mises stress of the trabecular calcaneus and talus were 3.21MPa and 2.41MPa respectively, while that of the Tresca stress were 3.46MPa and 2.55MPa. About 94% and 84% of the trabecular calcaneus and talus exceeded the shear yielding stress, while 21.7% and 18.3% yielded the compressive stress. The peak stresses were distributed around the talocalcaneal articulation and the calcaneal tuberosity inferiorly, which corresponded to the common fracture sites.ConclusionsThe prediction in this study showed that axial compressive impact at 5.0 m/s could produce considerable yielding of trabecular bone in both calcaneus and talus, dominantly by shear and compounded with compression that predispose the rearfoot in the risk of fracture. This study suggested the injury pattern and fracture mode of high energy trauma that provides insights in injury prevention and fracture management.     

Propionyl-L-Carnitine Enhances Wound Healing and Counteracts Microvascular Endothelial Cell Dysfunction

BackgroundImpaired wound healing represents a high cost for health care systems. Endothelial dysfunction characterizes dermal microangiopathy and contributes to delayed wound healing and chronic ulcers. Endothelial dysfunction impairs cutaneous microvascular blood flow by inducing an imbalance between vasorelaxation and vasoconstriction as a consequence of reduced nitric oxide (NO) production and the increase of oxidative stress and inflammation. Propionyl-L-carnitine (PLC) is a natural derivative of carnitine that has been reported to ameliorate post-ischemic blood flow recovery.ConclusionPLC treatment improved rat skin flap viability, accelerated wound healing and dermal angiogenesis. The beneficial effects of PLC likely derived from improvement of mitochondrial β-oxidation and reduction of Nox4-mediated oxidative stress and endothelial dysfunction. Antioxidant therapy and pharmacological targeting of endothelial dysfunction may represent a promising tool for the treatment of delayed wound healing or chronic ulcers.     

糖尿病患者足部溃疡感染的病原菌分布及药敏性分析

目的:研究糖尿病患者足部溃疡感染的病原菌分布及药敏性。方法:选取2016年2月至2017年2月我院收治的糖尿病足患者102例作为研究对象,采用全自动细菌鉴定仪和Kirby-Baure(K-B)法分别检测所有患者足部溃疡分泌物中病原菌分布和药敏性。结果:96例成功分离出菌株的糖尿病患者足部溃疡分泌物中共分离出107株菌株,其中革兰阴性菌61株(57.01%)、革兰阳性菌43株(40.19%)和真菌3株(2.80%),占总菌株百分比前三位的病原菌分别为金黄色葡萄球菌22株(20.56%)、奇异变形杆菌14株(13.08%)和肺炎克雷伯菌10株(9.35%);前三位革兰阴性菌(奇异变形杆菌、肺炎克雷伯菌和大肠埃希菌)对亚胺培南、美罗培南、头孢哌酮及阿米卡星的敏感性较高(高于90.00%);金黄色葡萄球菌和表皮葡萄球菌对万古霉素、利奈唑胺及利福平敏感性较高(高于95.00%);粪肠球菌对红霉素、氨苄西林、万古霉素及利奈唑胺敏感性较高(高于90.00%)。结论:糖尿病患者足部溃疡感染的病原菌以金黄色葡萄球菌和奇异变形杆菌为主,耐药情况严峻,临床诊疗过程中应根据药敏结果规范使用抗菌药物。     

Tool for Rapid & Easy Identification of High Risk Diabetic Foot: Validation & Clinical Pilot of the Simplified 60 Second Diabetic Foot Screening Tool

Background

Most diabetic foot amputations are caused by ulcers on the skin of the foot i.e. diabetic foot ulcers. Early identification of patients at high risk for diabetic foot ulcers is crucial. The ‘Simplified 60-Second Diabetic Foot Screening Tool’ has been designed to rapidly detect high risk diabetic feet, allowing for timely identification and referral of patients needing treatment. This study aimed to determine the clinical performance and inter-rater reliability of ‘Simplified 60 Second Diabetic Foot Screening Tool’ in order to evaluate its applicability for routine screening.

Methods and Findings

The tool was independently tested by n=12 assessors with n=18 Guyanese patients with diabetes. Inter-rater reliability was assessed by calculating Cronbach’s alpha for each of the assessment items. A minimum value of 0.60 was considered acceptable. Reliability scores of the screening tool assessment items were: ‘monofilament test’ 0.98; ‘active ulcer’ 0.97; ‘previous amputation’ 0.97; ‘previous ulcer’ 0.97; ‘fixed ankle’ 0.91; ‘deformity’ 0.87; ‘callus’ 0.87; ‘absent pulses’ 0.87; ‘fixed toe’ 0.80; ‘blisters’ 0.77; ‘ingrown nail’ 0.72; and ‘fissures’ 0.55. The item ‘stiffness in the toe or ankle’ was removed as it was observed in only 1.3% of patients. The item ‘fissures’ was also removed due to low inter-rater reliability. Clinical performance was assessed via a pilot study utilizing the screening tool on n=1,266 patients in an acute care setting in Georgetown, Guyana. In total, 48% of patients either had existing diabetic foot ulcers or were found to be at high risk for developing ulcers.

Conclusions

Clinicians in low and middle income countries such as Guyana can use the Simplified 60-Second Diabetic Screening Tool to facilitate early detection and appropriate treatment of diabetic foot ulcers. Implementation of this screening tool has the potential to decrease diabetes related disability and mortality.     

Simultaneous shear and pressure sensor array for assessing pressure and shear at foot/ground interface

Foot ulceration is a diabetic complication estimated to result in over $1 billion worth of medical expenses per year in the United States alone. This multifaceted problem involves the response of plantar soft tissue to both external forces applied to the epidermis and internal changes such as vascular supply and neuropathy. Increasing evidence indicates that a combination of elevated external forces (pressure and shear) and altered tissue properties is key to the etiology of foot ulcers. The overall goal of this research is to develop a platform-type hardware system that will allow a clinician to measure three-dimensional stress tensors (i.e. pressure and shear patterns) on the plantar surface and identify areas of concern. Experimental results have demonstrated that an optical approach can provide clear indication of both shear and pressure from 50 to 400 kPa with a frequency response of 100 Hz, a stress measurement accuracy of 100 Pa and a spatial resolution of 8.0mm. Initial evaluation of the system shows strong correlation between (i) applied shear and normal stress loads and (ii) the optical phase retardance computed for each stress axis of the polymer-based stress-sensing elements. These special sensing elements are designed to minimize the need for repeated calibration procedures-an issue that has plagued other attempts to develop multisensor shear and pressure systems.     

Evolución clínica y funcional de los pacientes que ingresan en residencias tras una fractura de cadera. Implementación de un programa de intervención multinivel

Background and objectiveThe aim of this study was to determine the clinical and functional outcomes of patients discharged to nursing homes after a hip fracture.MethodsThe study included all patients admitted to a group of nursing homes after a hip fracture in 2016. A geriatric assessment protocol was applied, and patients were treated with a specific protocol for 90 days. They were assessed for nutritional status (Mini-Nutritional Assessment and Body Mass Index), pain (Visual Analogue Scale, and the PAINAD Scale), the presence of pressure ulcers, blood test (D vitamin, haemoglobin, proteins), and functional status (Barthel index and Functional Assessment Categories).ResultsOut of a total of 175 patients, 116 (75%) met the inclusion criteria. The mean age was 84.9 years old (±6.7 SD), and 91 (78.4%) were women. At admission, 73.8% of 65 residents had anaemia, 76.7% hypovitaminosis D, 88% malnutrition or «at risk of malnutrition», and 15.3% had pressure ulcers. After 90 days, the moderate-severe functional status (Barthel index < 60) was reduced from 90.4 to 39.6%, dependence due to gait from 97.3 to 36.1%, and moderate-severe pain from 88.9 to 14.4%. Most of the pressure ulcers healed (94.4%).ConclusionsPatients admitted to nursing homes after a hip fracture had poor clinical and functional status. This study shows that after 90 days from admission these patients had positive outcomes in terms of functionality, gait, pain control, and pressure ulcers healing.     

Numerical Models for the Simulation of Flexible Artificial Heart Valves: Part I - Computational Methods

Abstract

A numerical model of the coupled motion of a flexing surface in a high Reynolds number flow is presented for the simulation of flexible polyurethane heart valves in the aortic position. This is achieved by matching a Lagrangian dynamic leaflet model with a panel method based flow solver. The two models are coupled via the time-dependent pressure field using the unsteady Bernoulli equation.

Incorporation of sub-cycling in the dynamic model equations and fast pre conditioning techniques in the panel method solver yields efficient convergence and near real-time simulations of valve motion. The generality of dynamic model allows different material properties and/or geometries to be studied easily and interactively. This interactivity is realized by embedding the models within a design environment created using the software IRIS Explorer ^TM.

Two flow domains are developed, an infinite domain and an internal domain using conformal mapping theory. In addition bending stress on the valve is computed using a simple stress model based on spline and circle equation techniques.     

Comparison of the effect of stem cell therapy and percutaneous transluminal angioplasty on diabetic foot disease in patients with critical limb ischemia

Background aimsThe aim of our study was to compare the effect of autologous stem cell therapy (SCT) and percutaneous transluminal angioplasty (PTA) on diabetic foot disease (DFD) in patients with critical limb ischemia (CLI).MethodsThirty-one patients with DFD and CLI treated by autologous stem cells and 30 patients treated by PTA were included in the study; 23 patients with the same inclusion criteria who could not undergo PTA or SCT formed the control group. Amputation-free survival, transcutaneous oxygen pressure (TcPO₂) and wound healing were assessed over 12 months.ResultsAmputation-free survival after 6 and 12 months was significantly greater in the SCT and PTA groups compared with controls (P = 0.001 and P = 0.0029, respectively) without significant differences between the active treatment groups. Increase in TcPO₂ did not differ between SCT and PTA groups until 12 months (both Ps < 0.05 compared with baseline), whereas TcPO₂ in the control group did not change over the follow-up period. More healed ulcers were observed up to 12 months in the SCT group compared with the PTA and control groups (84 versus 57.7 versus 44.4 %; P = 0.042).ConclusionsOur study showed comparable effects of SCT and PTA on CLI, a major amputation rate that was superior to conservative therapy in patients with diabetic foot and an observable effect of SCT on wound healing. Our results support SCT as a potential promising treatment in patients with CLI and diabetic foot.     

Polymicrobial nature of chronic diabetic foot ulcer biofilm infections determined using bacterial tag encoded FLX amplicon pyrosequencing (bTEFAP)

Background

Diabetic extremity ulcers are associated with chronic infections. Such ulcer infections are too often followed by amputation because there is little or no understanding of the ecology of such infections or how to control or eliminate this type of chronic infection. A primary impediment to the healing of chronic wounds is biofilm phenotype infections. Diabetic foot ulcers are the most common, disabling, and costly complications of diabetes. Here we seek to derive a better understanding of the polymicrobial nature of chronic diabetic extremity ulcer infections.

Methods and Findings

Using a new bacterial tag encoded FLX amplicon pyrosequencing (bTEFAP) approach we have evaluated the bacterial diversity of 40 chronic diabetic foot ulcers from different patients. The most prevalent bacterial genus associated with diabetic chronic wounds was Corynebacterium spp. Findings also show that obligate anaerobes including Bacteroides, Peptoniphilus, Fingoldia, Anaerococcus, and Peptostreptococcus spp. are ubiquitous in diabetic ulcers, comprising a significant portion of the wound biofilm communities. Other major components of the bacterial communities included commonly cultured genera such as Streptococcus, Serratia, Staphylococcus and Enterococcus spp.

Conclusions

In this article, we highlight the patterns of population diversity observed in the samples and introduce preliminary evidence to support the concept of functional equivalent pathogroups (FEP). Here we introduce FEP as consortia of genotypically distinct bacteria that symbiotically produce a pathogenic community. According to this hypothesis, individual members of these communities when they occur alone may not cause disease but when they coaggregate or consort together into a FEP the synergistic effect provides the functional equivalence of well-known pathogens, such as Staphylococcus aureus, giving the biofilm community the factors necessary to maintain chronic biofilm infections. Further work is definitely warranted and needed in order to prove whether the FEPs concept is a viable hypothesis. The findings here also suggest that traditional culturing methods may be extremely biased as a diagnostic tool as they select for easily cultured organisms such as Staphylococcus aureus and against difficult to culture bacteria such as anaerobes. While PCR methods also have bias, further work is now needed in comparing traditional culture results to high-resolution molecular diagnostic methods such as bTEFAP.     

Three-dimensional finite element analysis of the foot during standing--a material sensitivity study

Information on the internal stresses/strains in the human foot and the pressure distribution at the plantar support interface under loading is useful in enhancing knowledge on the biomechanics of the ankle-foot complex. While techniques for plantar pressure measurements are well established, direct measurement of the internal stresses/strains is difficult. A three-dimensional (3D) finite element model of the human foot and ankle was developed using the actual geometry of the foot skeleton and soft tissues, which were obtained from 3D reconstruction of MR images. Except the phalanges that were fused, the interaction among the metatarsals, cuneiforms, cuboid, navicular, talus, calcaneus, tibia and fibula were defined as contact surfaces, which allow relative articulating movement. The plantar fascia and 72 major ligaments were simulated using tension-only truss elements by connecting the corresponding attachment points on the bone surfaces. The bony and ligamentous structures were embedded in a volume of soft tissues. The encapsulated soft tissue was defined as hyperelastic, while the bony and ligamentous structures were assumed to be linearly elastic. The effects of soft tissue stiffening on the stress distribution of the plantar surface and bony structures during balanced standing were investigated. Increases of soft tissue stiffness from 2 and up to 5 times the normal values were used to approximate the pathologically stiffened tissue behaviour with increasing stages of diabetic neuropathy. The results showed that a five-fold increase in soft tissue stiffness led to about 35% and 33% increase in the peak plantar pressure at the forefoot and rearfoot regions, respectively. This corresponded to about 47% decrease in the total contact area between the plantar foot and the horizontal support surface. Peak bone stress was found at the third metatarsal in all calculated cases with a minimal increase of about 7% with soft tissue stiffening.