The diabetic foot

Nanotechnology in the Diagnosis and Treatment of Osteomyelitis

Infection remains one of the largest threats to global health. Among those infections that are especially troublesome, osteomyelitis, or inflammation of the bone, typically due to infection, is a particularly difficult condition to diagnose and treat. This difficulty stems not only from the biological complexities of opportunistic infections designed to avoid the onslaught of both the host immune system as well as exogenous antibiotics, but also from changes in the host vasculature and the heterogeneity of infectious presentations. While several groups have attempted to classify and stage osteomyelitis, controversy remains, often delaying diagnosis and treatment. Despite a host of preclinical treatment advances being incubated in academic and company research and development labs worldwide, clinical treatment strategies remain relatively stagnant, including surgical debridement and lengthy courses of intravenous antibiotics, both of which may compromise the overall health of the bone and the patient. This manuscript reviews the current methods for diagnosing and treating osteomyelitis and then contemplates the role that nanotechnology might play in the advancement of osteomyelitis treatment.

Diabetic Foot Infections: The Diagnostic Challenges

Diabetic foot infections (DFIs) are severe complications of long-standing diabetes, and they represent a diagnostic challenge, since the differentiation between osteomyelitis (OM), soft tissue infection (STI), and Charcot’s osteoarthropathy is very difficult to achieve. Nevertheless, such differential diagnosis is mandatory in order to plan the most appropriate treatment for the patient. The isolation of the pathogen from bone or soft tissues is still the gold standard for diagnosis; however, it would be desirable to have a non-invasive test that is able to detect, localize, and evaluate the extent of the infection with high accuracy. A multidisciplinary approach is the key for the correct management of diabetic patients dealing with infective complications, but at the moment, no definite diagnostic flow charts still exist. This review aims at providing an overview on multimodality imaging for the diagnosis of DFI and to address evidence-based answers to the clinicians when they appeal to radiologists or nuclear medicine (NM) physicians for studying their patients.

Ultrasonographic features of acute Charcot neuroarthropathy of the foot: a pilot study

OBJECTIVES

Our aim was to characterize the ultrasonographic features of patients with acute Charcot neuroarthropathy (CN) of the foot.

METHODS

In this prospective study, 26 patients with CN of the foot proved by MRI were enrolled. All patients were in early stage of CN with normal radiography (grade 0 modified Eichenholtz classification system). Ultrasonographic examination of mid-tarsal and ankle joints was performed with a 7-15 MHz linear probe.

RESULTS

Ages of our patients ranged from 38 to 67 years (57.3 ± 6.4). About 96.2% of our patients (25 patients) had diabetes mellitus. Ultrasonographic findings were as follows: effusion/synovitis (100%) with high Doppler activity (92.3%) in the mid-tarsal joints, and effusion/synovitis (92.3%) and high Doppler activity (84.6%) in the ankle joints. Bone erosions were present in the distal fibula in 23 patients (79.3%), while in distal tibia in 9 patients (34.6%). Tendonitis was found in tibialis posterior tendons in 23 patients (88.4%), and in peroneal tendons in 22 patients (84.6%). A combination of active synovitis (in mid-tarsal joints and ankle joints), active tendonitis (of tibialis posterior and peroneal tendons), and erosions in the distal end of fibula was present in 21 patients (80.8%).

CONCLUSIONS

Ultrasonography is able to detect soft tissue inflammation and pre-radiographic bony changes in early stages of CN. Key Points •Ultrasound is a useful diagnostic tool for pre-radiographic stages of Charcot joint. •High-grade synovitis, high-grade tenosynovitis, and bony erosions are highly suggestive of Charcot arthropathy.

Clinical features, radiological characteristics and offloading modalities in stage 0 Acute Charcot's neuroarthropathy - A single centre experience from South India

AIMS

Stage 0 Acute Charcot's Neuroarthropathy (ACN)in Type 2 Diabetes patients is a challenging diagnosis with subtle clinical features and normal appearing plain radiographs of the affected foot. Delay in diagnosis can lead to progression of disease and irreversible deformities. There is a paucity of data on Stage 0 ACN from India. The aim of this study was to assess clinical and radiological characteristics and treatment outcomes in Indian Type 2 Diabetes patients with Stage 0 ACN.

MATERIALS AND METHODS

A comparative, case-control study was carried out amongst patients attending the Integrated Diabetes Foot Clinic at a tertiary care South Indian hospital. During the 3-year study period, a total of 1811 patients with Type 2 Diabetes Mellitus were screened. Of these, n = 10 patients with stage 0 ACN Charcot's arthropathy were identified based on clinical features and MRI imaging of the foot for confirmation of diagnosis. These were compared with an age and duration of diabetes-matched group of n = 50 patients without ACN as controls.

RESULTS

Our study identified 10 patients (0.5%) with Stage 0 Acute charcot neuroarthropathy (ACN) in the study population. Those with ACN had higher BMI, poorer glycaemic control and greater degree of peripheral neuropathy (p < 0.05). Clinically relative lack of pain and infrared thermometric temperature difference >2 °C in the affected foot were the most significant findings, while MRI foot was useful in early detection of active and severe stage 0 disease. Total contact cast was the preferred initial offloading modality, with delay in initiating complete immobilization leading to worse outcomes.

CONCLUSIONS

This is the first study to highlight the characteristic features of Stage 0 ACN in Indian Type 2 Diabetes patients. Thorough clinical evaluation, infrared thermometry and radiological findigs on MRI foot leads to early disease detection. Complete offloading, preferably with total contact casts can prevent disease progression and chronic deformities.

Reevaluating Magnetic Resonance Imaging in Radiographically Suspected Osteomyelitis of the Toe

BACKGROUND:

Magnetic resonance imaging (MRI) is both sensitive and specific in the diagnosis of osteomyelitis, and it is an important imaging modality in preoperative planning of resection of infected bone. In many cases, however, the extent of osseous infection is evident on plain radiographs, and little additional information is gained from the MRI. The goal of this study was to assess the accuracy of radiographs against MRIs in assessing the spread of suspected osteomyelitis from one phalanx to another or to a metatarsal.

METHODS:

A medical record review was performed, and 14 patients with 16 toes confirmed to have osteomyelitis involving one or more phalanges were included in the study. An investigator blinded to the MRI findings interpreted the extent of osseous involvement based solely on the radiographic and clinical presentation. The accuracy of the radiographic interpretation was then calculated against the MRI findings.

RESULTS:

In 14 of the 16 toes (87.5%), whether osteomyelitis had spread from one bone to another was determined based on the radiographic and clinical presentation. In one toe, the radiograph did not adequately depict osteomyelitis in adjacent infected bone. In one more toe, the radiograph depicted features of osteomyelitis in uninfected bone.

CONCLUSIONS:

In a large percentage of patients, the phalanges affected by osteomyelitis had visible findings on the radiograph, and operative planning could have been based on the radiograph alone.

Diagnosis and treatment of necrotising otitis externa and diabetic foot osteomyelitis - similarities and differences

OBJECTIVE

Necrotising otitis externa is a severe inflammatory process affecting soft tissue and bone, mostly in diabetic patients. Diabetic patients are also at risk of diabetic foot osteomyelitis, another inflammatory condition involving soft tissue and bone. This review aimed to describe the similarities and differences of these entities in an attempt to further advance the management of necrotising otitis externa.

METHOD

A PubMed search was conducted using the key words 'otitis externa', 'necrotising otitis externa', 'malignant otitis externa', 'osteomyelitis' and 'diabetic foot'.Results and conclusionThe similarities regarding patient population and pathophysiology between necrotising otitis externa and diabetic foot osteomyelitis raise basic questions concerning the effects of long-standing diabetes on the external ear. The concordance between local swabs and bone cultures in diabetic foot osteomyelitis is less than 50 per cent. If this holds true also to necrotising otitis externa, the role of deep tissue cultures should be strongly considered. Similar to diabetic foot osteomyelitis, magnetic resonance imaging should be considered in selected necrotising otitis externa subgroups.

Autoantibodies to post-translationally modified type I and II collagen in Charcot neuroarthropathy in subjects with type 2 diabetes mellitus

AIMS

Charcot neuroarthropathy (CN) is a disabling complication, culminating in bone destruction and involving joints and articular cartilage with high inflammatory environment. Its real pathogenesis is as yet unknown. In autoinflammatory diseases, such as rheumatoid arthritis, characterized by inflammation and joint involvement, autoantibodies against oxidative post-translationally modified (oxPTM) collagen type I (CI) and type II (CII) were detected. Therefore, the aim of our study was to assess the potential involvement of autoimmunity in charcot neuroarthropathy, investigating the presence of autoantibodies oxPTM-CI and oxPTM-CII, in participants with charcot neuroarthropathy.

METHODS

In this case-control study, we enrolled 124 participants with type 2 diabetes mellitus (47 with charcot neuroarthropathy, 37 with diabetic peripheral neuropathy without charcot neuroarthropathy, and 40 with uncomplicated diabetes), and 32 healthy controls. The CI and CII were modified with ribose and other oxidant species, and the modifications were evaluated with sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Binding of sera from the participants was analyzed with enzyme-linked immunosorbent assay.

RESULTS

Age, body mass index, waist and hip circumferences, and lipid profile were similar across the 4 groups, as well as glycated hemoglobin and duration of diabetes among people with diabetes. An increased binding to both native and all oxidation-modified forms of CII was found in participants with CN and diabetic neuropathy. Conversely, for CI, an aspecific increased reactivity was noted.

CONCLUSIONS

Our results detected the presence of autoantibodies against oxidative post-translational modified collagen, particularly type 2 collagen, in participants with charcot neuroarthropathy and diabetic neuropathy, suggesting the possible involvement of autoimmunity. Further studies are required to understand the role of autoimmunity in the pathogenesis of charcot neuroarthropathy.

Magnetic resonance imaging of diabetic foot complications

This pictorial review aims to illustrate the various manifestations of the diabetic foot on magnetic resonance (MR) imaging. The utility of MR imaging and its imaging features in the diagnosis of pedal osteomyelitis are illustrated. There is often difficulty encountered in distinguishing osteomyelitis from neuroarthropathy, both clinically and on imaging. By providing an accurate diagnosis based on imaging, the radiologist plays a significant role in the management of patients with complications of diabetic foot.

Expression of the receptor activator of nuclear factor-kB ligand in peripheral blood mononuclear cells in patients with acute Charcot neuroarthropathy

Introduction. The receptor activator of nuclear factor-kB (RANK), ligand (RANK-L) and osteoprotegerin (OPG) are implicated in the pathogenesis of acute Charcot neuroarthropathy (CN). Materials and Methods. This study aimed to investigate the expression of RANK-L and OPG in peripheral blood mononuclear cells (PBMC) from patients with acute CN. Results. We found that the expression of RANK-L was lower in patients with acute CN as compared with diabetic control subjects and healthy control participants; whereas OPG expression was not detected in patients and in both control groups. RANK-L expression at the onset of disease was inversely correlated with the index of polyunsaturation (PUI), a bone marrow MRS-derived measurable index that allows evaluation of disease activity in acute CN, and recovery time. Finally, the expression of RANK-L increased at the time of healing compared with the values found during the acute phase. Conclusions. In conclusion, our preliminary data provide a first step in applying analysis of RANK-L expression in peripheral blood cells to the diagnosis of acute CN. Based on our data we also suggest that analysis of RANK-L expression could be a complementary tool that can be employed to obtain quantitative parameters that may help clinicians to monitor disease activity in patients with acute CN.

The diabetic foot in 2015: an overview

In 2015, it can be said that the diabetic foot is no longer the Cinderella of diabetic complications. Thirty years ago there was little evidence-based research taking place on the diabetic foot, and there were no international meetings addressing this topic. Since then, the biennial Malvern Diabetic Foot meetings started in 1986, the American Diabetes Association founded their Foot Council in 1987, and the European Association for the Study of Diabetes established a Foot Study Group in 1998. The first International Symposium on the Diabetic Foot in The Netherlands was convened in 1991, and this was soon followed by the establishment of the International Working Group on the Diabetic Foot that has produced useful guidelines in several areas of investigation and the management of diabetic foot problems. There has been an exponential rise in publications on diabetic foot problems in high impact factor journals, and a comprehensive evidence-base now exists for many areas of treatment. Despite the extensive evidence available, it, unfortunately, remains difficult to demonstrate that most types of education are efficient in reducing the incidence of foot ulcers. However, there is evidence that education as part of a multi-disciplinary approach to diabetic foot ulceration plays a pivotal role in incidence reduction. With respect to treatment, strong evidence exists that offloading is the best modality for healing plantar neuropathic foot ulcers, and there is also evidence from two randomized controlled trials to support the use of negative-pressure wound therapy in complex post-surgical diabetic foot wounds. Hyperbaric oxygen therapy exhibits the same evidence level and strength of recommendation. International guidelines exist on the management of infection in the diabetic foot. Many randomized trials have been performed, and these have shown that the agents studied generally produced comparable results, with the exception of one study in which tigecycline was shown to be clinically inferior to ertapenem ± vancomycin. Similarly, there are numerous types of wound dressings that might be used in treatment and which have shown efficacy, but no single type (or brand) has shown superiority over others. Peripheral artery disease is another major contributory factor in the development of ulceration, and its presence is a strong predictor of non-healing and amputation. Despite the proliferation of endovascular procedures in addition to open revascularization, many patients continue to suffer from severely impaired perfusion and exhaust all treatment options. Finally, the question of the true aetiopathogenesis of Charcot neuroarthropathy remains enigmatic, although much work is currently being undertaken in this area. In this area, it is most important to remember that a clinically uninfected, warm, insensate foot in a diabetic patient should be considered as a Charcot foot until proven otherwise, and, as such, treated with offloading, preferably in a cast.

MDCT assessment of CAD in type-2 diabetic subjects with diabetic neuropathy: the role of Charcot neuro-arthropathy

OBJECTIVES

To compare the CACS and CAD severity assessed by MDCT in neuropathic type-2 diabetic patients with and without Charcot-neuroarthropathy (CN).

METHODS

Thirty-four CN asymptomatic-patients and 36 asymptomatic-patients with diabetic-neuropathy (DN) without CN underwent MDCT to assess CACS and severity of CAD. Patients were classified as positive for significant CAD in presence of at least one stenosis >50 % on MDCT-coronary-angiography (MDCT-CA). Groups were matched for age, sex and traditional CAD risk-factors. The coronary-angiography (CA) was performed in all patients with at least a significant stenosis detected by MDCT-CA, both as reference and eventually as treatment.

RESULTS

CN patients showed higher rates of significant CAD in comparison with DN subjects [p < 0.001], while non-significant differences were observed in CACS (p = 0.980). No significant differences were also observed in CACS distribution in all subjects for stenosis ≥/<50 % (p = 0.814), as well as in both groups (p = 0.661 and 0.559, respectively). The MDCT-CA showed an overall diagnostic-accuracy for significant CAD of 87%.

CONCLUSIONS

These preliminary data suggest that CN-patients have a higher prevalence of severe CAD in comparison with DN-patients, while coronary plaques do not exhibit an increased amount of calcium. MDCT may be helpful to assess the CV risk in such asymptomatic type-2-diabetic patients with autonomic-neuropathy.

KEY POINTS

Type 2-diabetic-patients with CN result having more severe coronary artery plaque-burden. MDCT-CA may stratify the CV risk in type 2-diabetic-patients with CN. Adequate diagnostic is mandatory for optimal management of type 2-diabetic-patients with CN.

18-F flourodeoxy glucose positron emission tomography-computed tomography imaging: A viable alternative to three phase bone scan in evaluating diabetic foot complications?

Background:

This paper is based on the initial findings from a prospective ongoing study to evaluate the efficacy of flourodeoxy glucose positron emission tomography-computed tomography (FDG-PET CT) in diabetic foot evaluation.

Objective:

The aim was to compare the diagnostic accuracies of three phase bone scan (TPBS) and FDG PET-CT (FDG-PET) in diabetic foot evaluation.

Methods:

Seventy-nine patients with complicated diabetic foot (osteomyelitis/cellulitis, Charcot's neuropathy) were prospectively investigated. TPBS (15 mci methylene di phosphonate [MDP] intravenous [IV]), followed by FDG-PET (5 mci IV) within 5 days were performed in all patients. Based on referral indication, patients grouped into Group I, n = 36, (?osteomyelitis/cellulitis) and Group II, n = 43 (?Charcot's neuropathy). Interpretation was based on intensity, extent, pattern of MDP and FDG uptake (standardized uptake value) along with CT correlation. Findings were compared with final diagnostic outcome based on bone/soft tissue culture in Group I and clinical, radiological or scintigraphic followup in Group II. Results: Group I: For diagnosing osteomyelitis, TP: TN: FP: FN were 14:5:2:2 by FDG PET and 13:02:05:03 by TPBS respectively. Sensitivity, specificity, positive predictive value and negative predictive value (NPV) of FDG-PET were 87.5%, 71%, 87.5% and 71% and 81.25%, 28.5%, 72% and 40% for TPBS, respectively. Group II: charcot's: cellulitis: Normal were 22:14:7 by FDG PET and 32:5:6 by TPBS, respectively.

Conclusion:

Flourodeoxy glucose PET-CT has a higher specificity and NPV than TPBS in diagnosing pedal osteomyelitis. TPBS, being highly sensitive is more useful than FDG-PET in detecting Charcot's neuropathy.

Atherosclerotic coronary plaque in subjects with diabetic neuropathy: the prognostic cardiovascular role of Charcot neuroarthropathy--a case-control study

The aim of this study was to investigate the severity of coronary artery disease (CAD) and the plaque composition in neuropathic type 2 diabetic subjects with and without Charcot neuroarthropathy (CN) undergoing multidetector computed tomography coronary angiography (MDCT-CA). The study was a single-center, observational, with unmatched case-control design. We selected 17 CN patients and 18 patients with diabetic neuropathy (DN) without CN. In all the patients, multidetector computed tomography was performed to assess the coronary artery calcium score (CACS) and degree of coronary artery stenosis. Patients were classified as positive in the presence of significant CAD if there was at least one stenosis >50 % on MDCT-CA. The invasive coronary angiography was performed in case of significant stenosis detected with MDCT-CA, both as reference to standard and eventually as treatment. Groups were matched for age, sex, and traditional CAD risk factors. As compared to DN individuals, CN exhibited higher rates of significant coronary stenoses (p = 0.027; OR 7.7 [1.3-43.5]). However, no significant differences were observed in the CACS, which reflects plaque burden, in the two groups (p = 0.759). No significant differences were observed comparing CACS distribution in all subjects for stenosis higher/equal or lower than 50 % (p = 0.320). Finally, no significant differences were observed comparing CACS distribution in CN and DN subjects for coronary stenoses higher/equal or lower than 50 %. Our results suggest that CN patients have a higher prevalence of severe coronary plaques compared to DN patients. Nevertheless, coronary plaques in CN patients did not exhibit an increased degree of calcification.

Osteomyelitis in the diabetic foot

Osteomyelitis (OM) is a common complication of diabetic foot ulcers and/or diabetic foot infections. This review article discusses the clinical presentation, diagnosis, and treatment of OM in the diabetic foot. Clinical features that point to the possibility of OM include the presence of exposed bone in the depth of a diabetic foot ulcer. Medical imaging studies include plain radiographs, magnetic resonance imaging, and bone scintigraphy. A high index of suspicion is also required to make the diagnosis of OM in the diabetic foot combined with clinical and radiological studies.

Is scintigraphy a guideline method in determining amputation levels in diabetic foot?

BACKGROUND

In this study, we aimed to evaluate the potential use of a 3-phase bone scintigraphy method to determine the level of amputation on treatment cost, morbidity and mortality, reamputation rates, and the duration of hospitalization in diabetic foot.

METHODS

Thirty patients who were admitted to our clinic between September 2008 and July 2009, with diabetic foot were included. All patients were evaluated according to age, gender, diabetes duration, 3-phase bone scintigraphy, Doppler ultrasound, amputation/reamputation levels, and hospitalization periods. Patients underwent 3-phase bone scintigraphy using technetium-99m methylene diphosphonate, and the most distal site of the region displaying perfusion during the perfusion and early blood flow phase was marked as the amputation level. Amputation level was determined by 3-phase bone scintigraphy, Doppler ultrasound, and inspection of the infection-free clear region during surgery.

RESULTS

The amputation levels of the patients were as follows: finger in six (20%), ray amputation in five (16.6%), transmetatarsal in one (3.3%), Lisfranc in two (6.6%), Chopart in seven (23.3%), Syme in one (3.3%), below-the-knee in six (20%), above the knee in one (3.3%), knee disarticulation in one (3.3%), and two patients underwent amputation at other centers. After primary amputation, reamputation was performed on seven patients, and one patient was treated with debridement for wound site problems. No mortality was encountered during study.

CONCLUSIONS

We conclude that 3-phase bone scintigraphy prior to surgery could be a useful method to determine the amputation level in a diabetic foot. We conclude that further, comparative, more comprehensive, long-term, and controlled studies are required.

Phase 3 study comparing tigecycline and ertapenem in patients with diabetic foot infections with and without osteomyelitis

A phase 3, randomized, double-blind trial was conducted in subjects with diabetic foot infections without osteomyelitis (primary study) or with osteomyelitis (substudy) to determine the efficacy and safety of parenteral (intravenous [iv]) tigecycline (150 mg once-daily) versus 1 g once-daily iv ertapenem ± vancomycin. Among 944 subjects in the primary study who received ≥1 dose of study drug, >85% had type 2 diabetes; ~90% had Perfusion, Extent, Depth/tissue loss, Infection, and Sensation infection grade 2 or 3; and ~20% reported prior antibiotic failure. For the clinically evaluable population at test-of-cure, 77.5% of tigecycline- and 82.5% of ertapenem ± vancomycin-treated subjects were cured. Corresponding rates for the clinical modified intent-to-treat population were 71.4% and 77.9%, respectively. Clinical cure rates in the substudy were low (<36%) for a subset of tigecycline-treated subjects with osteomyelitis. Nausea and vomiting occurred significantly more often after tigecycline treatment (P = 0.003 and P < 0.001, respectively), resulting in significantly higher discontinuation rates in the primary study (nausea P = 0.007, vomiting P < 0.001). In the primary study, tigecycline did not meet criteria for noninferiority compared with ertapenem ± vancomycin in the treatment of subjects with diabetic foot infections.

Diagnostic performance of Fluorine-18-Fluorodeoxyglucose positron emission tomography for the diagnosis of osteomyelitis related to diabetic foot: a systematic review and a meta-analysis

OBJECTIVE

To systematically review and meta-analyse published data about the diagnostic performance of Fluorine-18-Fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) and PET/computed tomography (PET/CT) in osteomyelitis related to diabetic foot.

METHODS

A comprehensive literature search of studies on (18)F-FDG-PET and PET/CT in patients with diabetic foot was performed. Pooled sensitivity, specificity, positive and negative likelihood ratio (LR+ and LR-) and diagnostic odds ratio (DOR) and area under the summary ROC curve of (18)F-FDG-PET and PET/CT in patients with osteomyelitis related to diabetic foot were calculated.

RESULTS

Nine studies comprising 299 patients with diabetic foot were included in the qualitative analysis (systematic review) and discussed. The quantitative analysis (meta-analysis) of four selected studies provided the following results on a per patient-based analysis: sensitivity was 74% [95% confidence interval (95%CI): 60-85%], specificity 91% (95%CI: 85-96%), LR+ 5.56 (95%CI: 2.02-15.27), LR- 0.37 (95%CI: 0.10-1.35), and DOR 16.96 (95%CI: 2.06-139.66). The area under the summary ROC curve was 0.874.

CONCLUSIONS

In patients with suspected osteomyelitis related to diabetic foot (18)F-FDG-PET and PET/CT demonstrated a high specificity, being potentially useful tools if combined with other imaging methods such as MRI. Nevertheless, the literature focusing on the use of (18)F-FDG-PET and PET/CT in this setting remains still limited.

Charcot foot in diabetes and an update on imaging

Charcot neuroarthropathy (CN) is a serious complication of diabetes mellitus that can cause major morbidity including limb amputation. Since it was first described in 1883, and attributed to diabetes mellitus in 1936, the diagnosis of CN has been very challenging even for the experienced practitioners. Imaging plays a central role in the early and accurate diagnosis of CN, and in distinction of CN from osteomyelitis. Conventional radiography, computed tomography, nuclear medicine scintigraphy, magnetic resonance imaging, and positron emission tomography are the imaging techniques currently in use for the evaluation of CN but modalities other than magnetic resonance imaging appeared to be complementary. This study focuses on imaging findings of acute and chronic neuropathic osteoarthropathy in diabetes and discrimination of infected vs. non-infected neuropathic osteoarthropathy.

Osteomyelitis in the diabetic foot: diagnosis and management

Although osteomyelitis of the foot in diabetes remains common in specialist foot clinics across the world, the quality of published work to guide clinicians in the diagnosis and management is generally poor. Diagnosis should be based primarily on clinical signs supported by results of pathologic and radiologic investigations. Although the gold standard comes from the histologic and microbiological examination of bone, clinicians should be aware of the problems of sampling error. This lack of standardization of diagnostic criteria and of consensus on the choice of outcome measures poses further difficulties when seeking evidence to support management decisions. Experts have traditionally recommended surgical removal of infected bone but available evidence suggests that in many cases (excepting those in whom immediate surgery is required to save life or limb) a nonsurgical approach to management of osteomyelitis may be effective for many, if not most, patients with osteomyelitis of the diabetic foot. The benefits and limitations of both approaches need, however, to be established in prospective trials so that appropriate therapy can be offered to appropriate patients at the appropriate time, with the patients' views taken fully into account.

Charcot neuroarthropathy of the foot and ankle: a review

Charcot neuroarthropathy is a limb-threatening, destructive process that occurs in patients with neuropathy associated with medical diseases such as diabetes mellitus. Clinicians' treating diabetic patients should be vigilant in recognizing the early signs of acute Charcot neuroarthropathy, such as pain, warmth, edema, or pathologic fracture in a neuropathic foot. Early detection and prompt treatment can prevent joint and bone destruction, which, if untreated, can lead to morbidity and high-level amputation. A high degree of suspicion is necessary. Once the early signs have been detected, prompt immobilization and offloading are important. Treatment should be determined on an individual basis, and it must be determined whether a patient can be treated conservatively or will require surgical intervention when entering the chronic phase. If diagnosed early, medical and conservative measures only will be required. Surgery is indicated for patients with severe or unstable deformities that, if untreated, will result in major amputations. A team approach that includes a foot and ankle surgeon, a diabetologist, a physiotherapist, a medical social councilor, and, most importantly, the patient and immediate family members is vital for successful management of this serious condition.

2012 Infectious Diseases Society of America clinical practice guideline for the diagnosis and treatment of diabetic foot infections

Foot infections are a common and serious problem in persons with diabetes. Diabetic foot infections (DFIs) typically begin in a wound, most often a neuropathic ulceration. While all wounds are colonized with microorganisms, the presence of infection is defined by ≥2 classic findings of inflammation or purulence. Infections are then classified into mild (superficial and limited in size and depth), moderate (deeper or more extensive), or severe (accompanied by systemic signs or metabolic perturbations). This classification system, along with a vascular assessment, helps determine which patients should be hospitalized, which may require special imaging procedures or surgical interventions, and which will require amputation. Most DFIs are polymicrobial, with aerobic gram-positive cocci (GPC), and especially staphylococci, the most common causative organisms. Aerobic gram-negative bacilli are frequently copathogens in infections that are chronic or follow antibiotic treatment, and obligate anaerobes may be copathogens in ischemic or necrotic wounds. Wounds without evidence of soft tissue or bone infection do not require antibiotic therapy. For infected wounds, obtain a post-debridement specimen (preferably of tissue) for aerobic and anaerobic culture. Empiric antibiotic therapy can be narrowly targeted at GPC in many acutely infected patients, but those at risk for infection with antibiotic-resistant organisms or with chronic, previously treated, or severe infections usually require broader spectrum regimens. Imaging is helpful in most DFIs; plain radiographs may be sufficient, but magnetic resonance imaging is far more sensitive and specific. Osteomyelitis occurs in many diabetic patients with a foot wound and can be difficult to diagnose (optimally defined by bone culture and histology) and treat (often requiring surgical debridement or resection, and/or prolonged antibiotic therapy). Most DFIs require some surgical intervention, ranging from minor (debridement) to major (resection, amputation). Wounds must also be properly dressed and off-loaded of pressure, and patients need regular follow-up. An ischemic foot may require revascularization, and some nonresponding patients may benefit from selected adjunctive measures. Employing multidisciplinary foot teams improves outcomes. Clinicians and healthcare organizations should attempt to monitor, and thereby improve, their outcomes and processes in caring for DFIs.

Role of dynamic MRI in the follow-up of acute Charcot foot in patients with diabetes mellitus

PURPOSE

To evaluate the usefulness of magnetic resonance imaging (MRI) in assessing the level of activity of acute Charcot foot, monitoring treatment response and predicting healing time.

MATERIALS AND METHODS

Forty diabetic patients with acute Charcot foot were prospectively enrolled. Patients underwent limb immobilization and were followed every 3 months by clinical examination (skin temperature and circumferences) and MRI. MR protocol included T1-weighted and fast spin echo inversion recovery (FSE-IR) sequences, and a dynamic study (fast spoiled gradient echo), after gadolinium administration (0.1 ml/kg). The contrast medium uptake rate at D-MRI and the signal intensity (SI) ratio on the FSE-IR sequence were measured.

RESULTS

At baseline, mean contrast medium uptake rate was 136 ± 49.7% and the mean SI ratio was 5 ± 3. A high intra- and inter-observer agreement was found for the contrast medium uptake rate, whereas a low agreement was observed for the SI ratio. At 3 months' follow-up, reduction of the contrast medium uptake rate was observed in all patients with improved clinical findings (n = 34), whereas the SI ratio was reduced in 15/34 (44.1%) patients. Mean healing time was significantly related to the baseline contrast medium uptake rate (P=0.005); it was 5.3 ± 2.7 months in patients with contrast medium uptake rate ≤ 100%, compared with 9.1 ± 2.5 months in the remaining patients (P=0.0003).

CONCLUSIONS

Contrast medium uptake rate obtained at D-MRI represents a reproducible parameter that is reliable for predicting and monitoring treatment outcome in acute Charcot foot.

Use of MR imaging in diagnosing diabetes-related pedal osteomyelitis

The clinical diagnosis of diabetes-related osteomyelitis relies on the identification and characterization of an associated foot ulcer, a method that is often unreliable. Magnetic resonance (MR) imaging is the modality of choice for imaging evaluation of pedal osteomyelitis. Because MR imaging allows the extent of osseous and soft-tissue infection to be mapped preoperatively, its use may limit the extent of resection. At MR imaging, the simplest method to determine whether osteomyelitis is present is to follow the path of an ulcer or sinus tract to the bone and evaluate the signal intensity of the bone marrow. Combined findings of low signal intensity in marrow on T1-weighted images, high signal intensity in marrow on T2-weighted images, and marrow enhancement after the administration of contrast material are indicative of osteomyelitis. Secondary signs of osteomyelitis include periosteal reaction, a subtending skin ulcer, sinus tract, cellulitis, abscess, and a foreign body. The location of a marrow abnormality is a key distinguishing feature of osteomyelitis: Whereas neuroarthropathy most commonly affects the tarsometatarsal and metatarsophalangeal joints, osteomyelitis occurs distal to the tarsometatarsal joint, in the calcaneus and malleoli. In the midfoot, secondary signs of infection help differentiate between neuroarthropathy and a superimposed infection.

Midfoot and hindfoot bone marrow edema identified by magnetic resonance imaging in feet of subjects with diabetes and neuropathic ulceration is common but of unknown clinical significance

OBJECTIVE

We conducted a retrospective cohort study assessing the prevalence and clinical and radiological outcome of remote areas of bone marrow edema on magnetic resonance imaging (MRI) in the feet of subjects with diabetes and neuropathic foot ulceration.

RESEARCH DESIGN AND METHODS

MRIs performed over 6 years looking for osteomyelitis associated with neuropathic lesions were assessed for remote areas of signal change.

RESULTS

Seventy MRI studies were assessed. Remote areas of signal change were present in 21 (30%) subjects, involved midfoot or hindfoot in 20 subjects, were associated with younger age and renal replacement therapy, and did not predict future Charcot neuroarthropathy or infection at that site. Repeat MRIs in 11 subjects with such areas found that none had progressed, six had improved, and two had resolved; in 29 subjects without such areas, five had developed new areas.

CONCLUSIONS

Bone marrow edema in the midfoot and hindfoot of subjects with diabetes and neuropathic lesions is common, often transient, and of unknown significance.

Management of osteomyelitis of the foot in diabetes mellitus

Although osteomyelitis occurs in approximately 10-20% of patients with diabetes-related foot ulcers, no widely accepted guideline is available for its treatment. In particular, little consensus exists on the place of surgery. A number of experts claim that early surgical excision of all infected or necrotic bone is essential. Others suggest that surgery should not be performed routinely, but instead only in patients who do not respond to antibiotic treatment or in case of particular clinical indications. Unfortunately, no studies have directly compared the two approaches. Over 500 cases of conservative (that is, nonsurgical) management with resolution rates of 60-80% have been described previously. Most patients in these series, however, received prolonged courses of broad-spectrum antibiotics, which increase the risk of diarrhea caused by Clostridium difficile or the emergence of multidrug-resistant organisms. By contrast, relatively few series of primarily surgical management have been published, with widely differing outcomes, and some of them also reported high recurrence rates. Further research is required to establish the relative importance of each approach, but the available data clearly indicate that a combined assessment and treatment by surgeons and physicians together is essential for many patients.

Association between osteoprotegerin G1181C and T245G polymorphisms and diabetic charcot neuroarthropathy: a case-control study

OBJECTIVE

Charcot neuroarthropathy is a disabling complication of diabetes. Although its pathogenesis remains unknown, we suppose that genetics may play a relevant role.

RESEARCH DESIGN AND METHODS

We performed a case-control study with 59 subjects with diabetic Charcot neuroarthropathy (Ch group), 41 with diabetic neuropathy without Charcot neuroarthropathy (ND group), and 103 healthy control subjects (H group) to evaluate the impact of two single nucleotide polymorphisms (SNPs) of the osteoprotegerin gene (G1181C and T245G) on the risk of Charcot neuroarthropathy.

RESULTS

Regarding the SNPs of G1181C, we found a significant linkage between the G allele and Charcot neuroarthropathy (Ch vs. ND, odds ratio [OR] 2.32 [95% CI 1.3-4.1], P = 0.006; Ch vs. H, 2.10 [1.3-3.3], P = 0.002; and ND vs. H, 0.90 [0.7-1.9], P = 0.452); similarly, we found a linkage with the G allele of T245G (Ch vs. ND, 6.25 [2.2-19.7], P < 0.001; Ch vs. H, 3.56 [1.9-6.7], P = 0.001; and ND vs. H, 0.54 [0.6-5.7], P = 0.304), supporting a protective role for the allele C and T, respectively. For this reason we investigated the frequency of the protective double homozygosis CC + TT (7% in Ch) that was significantly lower in Ch compared with H (0.18 [0.06-0.5], P = 0.002) and with ND (0.17 [0.05-0.58], P = 0.006), whereas there was no difference between H and ND (1.05 [0.43-2.0], P = 0.468). In a multivariate logistic backward regression model, only weight and the lack of CC and TT genotypes were independently associated with the presence of Charcot neuroarthropathy.

CONCLUSIONS

This is the first study that shows an association between genetic regulation of bone remodeling and Charcot neuroarthropathy.

Current concepts in imaging diabetic pedal osteomyelitis

Diabetic pedal osteomyelitis is primarily a manifestation of vascular insufficiency with resultant tissue ischemia, neuropathy, and infection. Nearly all cases of pedal osteomyelitis arise from a contiguous ulcer and soft tissue infection. MR imaging is the modality of choice to assess for the presence of osteomyelitis and associated soft tissue complications, to guide patient management, and to aid in limited limb resection.

Diagnostic accuracy of the physical examination and imaging tests for osteomyelitis underlying diabetic foot ulcers: meta-analysis

Accurate diagnosis of osteomyelitis underlying diabetic foot ulcers is essential to optimize outcomes. We undertook a meta-analysis of the accuracy of diagnostic tests for osteomyelitis in diabetic patients with foot ulcers. Pooled sensitivity and specificity, the summary measure of accuracy (Q*), and diagnostic odds ratio were calculated. Exposed bone or probe-to-bone test had a sensitivity of 0.60 and a specificity of 0.91. Plain radiography had a sensitivity of 0.54 and a specificity of 0.68. MRI had a sensitivity of 0.90 and a specificity of 0.79. Bone scan was found to have a sensitivity of 0.81 and a specificity of 0.28. Leukocyte scan was found to have a sensitivity of 0.74 and a specificity of 0.68. The diagnostic odds ratios for clinical examination, radiography, MRI, bone scan, and leukocyte scan were 49.45, 2.84, 24.36, 2.10, and 10.07, respectively. The presence of exposed bone or a positive probe-to-bone test result is moderately predictive of osteomyelitis. MRI is the most accurate imaging test for diagnosis of osteomyelitis.

Assessment and treatment of diabetic foot ulcer

BACKGROUND AND OBJECTIVES

Foot ulcers are one of the main complications in diabetes mellitus, with a 15% lifetime risk in all diabetic patients. The rate of lower extremity amputation among diabetic patients is 17-40 times higher than in non-diabetics. A critical triad of neuropathy, minor foot trauma and foot deformity was found in > 63% of diabetic foot ulcers (DFU). Peripheral vascular disease (PVD) has been identified in 30% of foot ulcers. We present a comprehensive assessment and the treatment of DFUs. We also want to notify physicians not to ignore foot assessment and examinations in patients with diabetes.

METHODS

We conducted this study on DFU on the basis of: pathogenesis and risk factors, assessment and physical examination, paraclinic assessment, treatment, cost and mortality and prevention.

RESULTS AND FINDINGS

Approximately 20% of hospital admissions among diabetic patients are the result of foot problems. Diabetic foot assessment should include dermatological, vascular, neurological and musculoskeletal systems. There are three basic treatments for management of DFU: (i) debridement; (ii) antibiotics and (iii) revascularization. The cost to treat one simple ulcer is $5000 to $8000.

CONCLUSION

Awareness of physicians about foot problems in diabetic patients, clinical examination and paraclinical assessment, regular foot examination, patient education, simple hygienic practices and provision of appropriate footwear combined with prompt treatment of minor injuries can decrease ulcer occurrence by 50%.

Nuclear medicine imaging of diabetic foot infection: results of meta-analysis

BACKGROUND AND AIM

Osteomyelitis of the foot is the most commonly encountered complication in diabetic patients. Nuclear medicine techniques are usually complementary to radiology in the diagnosis of foot infections; they play an important role in various clinical situations. The aim of this study was to develop a practical guideline to describe the radiopharmaceuticals to be used for different clinical conditions and different aims in diabetic foot infection.

METHODS

In this study, we reviewed 57 papers (published between 1982 and 2004; 50 original papers and seven reviews) that described the imaging of the diabetic foot and examined a total of 2889 lesions. We performed data analysis to establish which imaging technique could be used as a 'gold standard' to diagnose infection, evaluate the extent of disease and monitor the efficacy of therapy.

RESULTS AND CONCLUSION

We provide a guideline to assist in the selection of the optimal radiopharmaceuticals for different clinical conditions and different aims.

The diabetic foot: Charcot joint and osteomyelitis

Foot problems are common causes of disability in diabetic patients with as many as 25% expected to develop severe foot or leg problems during their lifetimes. Although skin ulceration is the most frequent problem, bones may also be involved in two different clinical conditions: osteomyelitis and Charcot osteoarthropathy. Osteomyelitis causes complications in up to one third of diabetic foot infections and is due to direct contamination from a soft-tissue ulcer. Osteoarthropathy Charcot foot is a chronic and progressive disease of the bone and joints. Both osteomyelitis and Charcot joint are conditions with an increased risk of lower limb amputation, both may have a successful outcome when recognized and treated in the early stages. The major diagnostic difficulty is in distinguishing bone infection (osteomyelitis) from non-infectious neuropathic bony disorders as in osteoarthropathy Charcot foot. An additional difficulty is found when a bone infection superimposes a Charcot osteopathy. This condition, which can be clinically suspected when foot ulceration appears in Charcot foot, needs to be diagnosed because it implies a different therapeutic strategy. This article aims to summarize both these two clinical conditions and give indications to make a timely and correct diagnosis.

Diabetic foot disorders. A clinical practice guideline (2006 revision)

The prevalence of diabetes mellitus is growing at epidemic proportions in the United States and worldwide. Most alarming is the steady increase in type 2 diabetes, especially among young and obese people. An estimated 7% of the US population has diabetes, and because of the increased longevity of this population, diabetes-associated complications are expected to rise in prevalence. Foot ulcerations, infections, Charcot neuroarthropathy, and peripheral arterial disease frequently result in gangrene and lower limb amputation. Consequently, foot disorders are leading causes of hospitalization for persons with diabetes and account for billion-dollar expenditures annually in the US. Although not all foot complications can be prevented, dramatic reductions in frequency have been achieved by taking a multidisciplinary approach to patient management. Using this concept, the authors present a clinical practice guideline for diabetic foot disorders based on currently available evidence, committee consensus, and current clinical practice. The pathophysiology and treatment of diabetic foot ulcers, infections, and the diabetic Charcot foot are reviewed. While these guidelines cannot and should not dictate the care of all affected patients, they provide evidence-based guidance for general patterns of practice. If these concepts are embraced and incorporated into patient management protocols, a major reduction in diabetic limb amputations is certainly an attainable goal.

The diagnosis of osteomyelitis of the foot in diabetes: microbiological examination vs. magnetic resonance imaging and labelled leucocyte scanning

AIMS

Foot infections and their sequelae are among the most common and severe complications of diabetes mellitus. As diabetic patients with foot infections develop osteomyelitis and may progress to amputation, early diagnosis of osteomyelitis is critical.

METHODS

We compared the diagnostic values of labelled leucocyte scanning with Tc(99)m, magnetic resonance imaging (MRI) and microbiological examination of bone tissue specimens with histopathology, the definitive diagnostic procedure. Thirty-one diabetic patients with foot lesions were enrolled in the study and histopathological examination was performed in all. Patients had clinically suspected foot lesions of > or = grade 3 according to the classification of Wagner.

RESULTS

Bone specimens were obtained for histopathological examination. Microbiology had a sensitivity of 92% and specificity of 60%. Labelled leucocyte scanning had a sensitivity of 91%, specificity of 67%, and MRI a sensitivity of 78%, specificity of 60%.

CONCLUSIONS

Microbiological examination may be as useful as and less costly than other diagnostic procedures and is the only method which can guide the choice of antibiotic therapy.

Evidence-Based Protocol for Diabetic Foot Ulcers

BACKGROUND

Diabetic foot ulcers are the single biggest risk factor for nontraumatic foot amputations in persons with diabetes. Foot ulcers occur in 12 to 25 percent of persons with diabetes and precede 84 percent of all nontraumatic amputations in this growing population. Because of the high incidence of foot ulcers, amputations remain a source of morbidity and mortality in persons with diabetes. Strict adherence to evidence-based protocols as described herein will prevent the majority of these amputations.

METHODS

The collective experience of treating patients with neuropathic diabetic foot ulcers in four major diabetic foot programs in the United States and Europe was analyzed.

RESULTS

The following protocol was developed for patients with diabetic foot ulcers: (1) establishment of good communication among the patient, the wound healing team, and the primary medical doctor; (2) comprehensive, protocol-driven care of the entire patient, including hemoglobin A1c, microalbuminuria, and cholesterol as well as early treatment of retinopathy, nephropathy, and cardiac disease; (3) weekly objective measurement of the wound with digital photography, planimetry, and documentation of the wound-healing process using the Wound Electronic Medical Record, if available; (4) objective evaluation of blood flow in the lower extremities (e.g., noninvasive flow studies); (5) débridement of hyperkeratotic, infected, and nonviable tissue; (6) use of systemic antibiotics for deep infection, drainage, and cellulitis; (7) off-loading; (8) maintenance of a moist wound bed; (9) use of growth factor and/or cellular therapy if the wound is not healing after 3 weeks with this protocol; and (10) consideration of the use of vacuum-assisted therapy in complex wounds.

CONCLUSIONS

In diabetic foot ulcers, availability of the above modalities, in combination with early recognition and comprehensive treatment, ensures rapid healing, minimizes morbidity and mortality rates, and eliminates toe and limb amputations in the absence of ischemia and osteomyelitis.

An integrated care pathway to save the critically ischaemic diabetic foot

This prospective study describes and evaluates the efficacy of an integrated care pathway for the management of the critically ischaemic diabetic foot patients by a multidisciplinary team. A weekly joint diabetes/vascular/podiatry ward round and outpatient clinic was established where patients were assessed within 7 days of referral by clinical examination, ankle-brachial-index-pressures, duplex angiogram and transcutaneous oxygen pressures. An angiogram +/- angioplasty or alternatively a magnetic resonance angiography prior to surgical revascularisation was performed in patients deemed not suitable for angioplasty based on the above vascular assessment. Between January 2002 and June 2003(18 months), 128 diabetic patients with lower limb ischaemia were seen. Thirty-four (26.6%) patients received medical treatment alone, and 18 (14.1%) were deemed 'palliative' due to their significant co-morbidities. The remaining 76 (59.4%) patients underwent either angioplasty (n = 56), surgical reconstruction (n = 18), primary major amputation (n = 2) or secondary amputation after surgical revascularisation (n = 1). Minor toe amputations were required in 35 patients. The mortality in the intervention group was 14% (11/76). This integrated multidisciplinary approach offers a consistent and equitable service to diabetic patients with critically ischaemic feet and appears to have a beneficial major/minor amputation ratio.

MRI of the diabetic foot: differentiation of infection from neuropathic change

The aim of this review is to illustrate the magnetic resonance imaging features that can help differentiate osteomyelitis from neuropathic osteoarthropathy in the foot.

A systematic approach to diabetic foot infections

Foot infection is the most common reason for hospitalization and subsequent lower extremity amputation among persons with diabetes. Foot ulceration caused by diabetic neuropathy, trauma, and peripheral vascular disease can lead to a limbor life-threatening infection. The optimum treatment of these potentially devastating conditions depends on a multidisciplinary approach that addresses the related or underlying disorders and thus ensures proper wound healing and a positive outcome. In addition to antibiotic therapy, severe soft-tissue or bone infections may necessitate surgical treatment, including drainage, débridement, and vascular reconstruction. Initial (empiric) antibiotic therapy should provide coverage against staphylococci and streptococci and should be revised according culture results. Antibiotic therapy is not indicated in clinically noninfected wounds. The duration of antibiotic treatment can range from 1 week for mild infections to 6 weeks or more for residual osteomyelitis and severe deep tissue infections. Aggressive (and sometimes repeated or staged) surgical intervention and appropriate antibiotic therapy can reduce the likelihood of a major amputation and the duration of hospitalization.