Bone and soft tissue infections in patients with diabetic foot

Engineered exosomes as a prospective therapy for diabetic foot ulcers

Diabetic foot ulcer (DFU), characterized by high recurrence rate, amputations and mortality, poses a significant challenge in diabetes management. The complex pathology involves dysregulated glucose homeostasis leading to systemic and local microenvironmental complications, including peripheral neuropathy, micro- and macro-angiopathy, recurrent infection, persistent inflammation and dysregulated re-epithelialization. Novel approaches to accelerate DFU healing are actively pursued, with a focus on utilizing exosomes. Exosomes are natural nanovesicles mediating cellular communication and containing diverse functional molecular cargos, including DNA, mRNA, microRNA (miRNA), lncRNA, proteins, lipids and metabolites. While some exosomes show promise in modulating cellular function and promoting ulcer healing, their efficacy is limited by low yield, impurities, low loading content and inadequate targeting. Engineering exosomes to enhance their curative activity represents a potentially more efficient approach for DFUs. This could facilitate focused repair and regeneration of nerves, blood vessels and soft tissue after ulcer development. This review provides an overview of DFU pathogenesis, strategies for exosome engineering and the targeted therapeutic application of engineered exosomes in addressing critical pathological changes associated with DFUs.

Infectious Extensor Tenosynovitis of the Hallucis Longus Tendon: A Case Report

Infectious tenosynovitis can involve both flexor and extensor tendons of the extremities. If left untreated, it can lead to high morbidity and mortality. Most emergency providers recognize the signs and symptoms of flexor and extensor tenosynovitis of the hand. However, extensor tenosynovitis of the hallucis longus tendon is a rare condition with a risk of complications similar to infectious tenosynovitis of the hand. This case report describes a presentation of extensor tenosynovitis of the hallucis longus tendon. Clinical suspicion is essential to help the provider not miss this rare condition, which can lead to significant morbidity if not treated promptly or appropriately.

Musculoskeletal infections through direct inoculation

Musculoskeletal infections consist of different clinical conditions that are commonly encountered in daily clinical settings. As clinical findings and even laboratory tests cannot always be specific, imaging plays a crucial role in the diagnosis and treatment of these cases. Musculoskeletal infections most commonly occur secondary to direct inoculation into the skin involuntarily affected by trauma, microorganism, foreign bodies, or in diabetic ulcers; direct infections can also occur from voluntary causes due to surgery, vaccinations, or other iatrogenic procedures. Hematogenous spread of infection from a remote focus can also be a cause for musculoskeletal infections. Risk factors for soft tissue and bone infections include immunosuppression, old age, corticosteroid use, systemic illnesses, malnutrition, obesity, and burns. Most literature discusses musculoskeletal infections according to the diagnostic tools or forms of infection seen in different soft tissue anatomical planes or bones. This review article aims to evaluate musculoskeletal infections that occur due to direct inoculation to the musculoskeletal tissues, by focusing on the traumatic mechanism with emphasis on the radiological findings.

Microbiological Pattern, Antimicrobial Resistance and Prevalence of MDR/XDR Organisms in Patients With Diabetic Foot Infection in an Indian Tertiary Care Hospital

Foot infections are the most prevalent problem in persons with diabetes. The burden of multidrug resistant (MDR) microorganisms in diabetic foot infections (DFIs) is rising day by day. Given that, the present study aims to determine the variety of microorganisms isolated from the diabetic foot ulcers (DFUs), and their antibiotic sensitivity pattern. This prospective observational study was conducted for 1 year at Bharati Hospital and Research Centre, Pune, India. Clinically infected patients with DFU admitted to the surgery ward were included in this study. The specimen for microbiological studies is obtained from the wound swabs, soft tissue, and bone tissue as a part of routine clinical care. All demographic, clinical data, microbial culture results were collected, and evaluated for each case. Antimicrobial susceptibility testing to different agents was carried out using the VITEK-2® machine. A total of 110 microorganisms were isolated from 76 specimens, with an average of 1.4 organisms per lesion. Staphylococcus aureus (n = 27, 24.5%) and Escherichia coli (n = 17, 15.4%) were the most prevalent Gram-positive and Gram-negative organisms isolated, respectively. MDR organisms constituted up to 52 (47.2%), while 6 (5.4%) of the samples were extensively drug resistant (XDR). Methicillin-resistant S aureus (MRSA) accounted for up to 19 (70.3%) of the S aureus isolates, likewise extended-spectrum beta-lactamase producing microorganisms constituted 16 (14.5%) of total isolates in this study. Oxacillin and benzyl penicillin exhibited least susceptibility against Gram-positive bacteria, among Gram-negative organisms; cefuroxime, ceftriaxone, and ciprofloxacin were least sensitive. As most of the S aureus isolate in our study was MRSA, empirical antimicrobial therapy may include coverage for MRSA in a patient with risk factors associated with this pathogen. A crucial observation is the presence of XDR strains of Proteus mirabilis in DFIs, which is resistant to almost all the antimicrobials, tested. Appropriate antimicrobial selection may reduce the morbidity and the emergence of MDR organisms in DFIs.

Non-Enhancing Tissue on Diabetic Foot Magnetic Resonance Imaging in Relation to Osteomyelitis Investigation: Magnetic Resonance Imaging Performance, Pitfalls and Clinical Considerations

Background: Geographic non-enhancing zones in diabetic foot magnetic resonance imaging (MRI) were first described in 2002. No previous report has described the impact and clinical significance of geographic non-enhancing tissue seen in the evaluation of diabetic foot MRI. Purpose: To evaluate the prevalence of devascularization areas on contrast-enhanced MRI in diabetic patients suspected of having foot osteomyelitis, the impact on the performance of the MRI assessment, and the possible pitfalls. Methods: A retrospective study was conducted between January 2016 and December 2017 during which 72 CE-MRIs of 1.5 and 3T were reviewed by 2 musculoskeletal radiologists for the presence of non-enhancing tissue areas and for osteomyelitis. A blinded third party collected clinical data including pathology reports, revascularization procedures, and surgical interventions. The prevalence of devascularization was calculated. Results: Among the 72 CE-MRIs (54 men, 18 women; mean age 64), 28 demonstrated non-enhancing areas (39%). All but 6 patients were found to have been correctly diagnosed on imaging (3 false positives, 2 false negatives, and 1 non-diagnostic). A greater discordance was also observed between the radiological and pathological diagnoses in the MRIs which showed non-enhancing tissue. Conclusion: Non-enhancing tissue is found in a non-negligible portion of diabetic foot MRIs and affects its diagnostic performance when looking for osteomyelitis. The recognition of these areas of devascularization may be helpful for the physician in planning the best treatment option for the patient.

The Role of Serial Radiographs in Diagnosing Diabetic Foot Bone Osteomyelitis

Background and Objective

Diagnosing diabetes-related foot osteomyelitis is sometimes a challenge for clinicians since it may occur without local or systemic signs of infection. Thus, the primary purpose of this article was to evaluate the role of progressive radiographic changes in diagnosing diabetic foot osteomyelitis.

Materials and Methods

A retrospective review of databases of our Institution was performed to identify all long-standing diabetic foot patients who underwent two radiographic examinations spaced no more than five weeks apart and a subsequent magnetic resonance (MR) examination from November 2015 to November 2020. A total of 46 patients (32 men, 14 women; mean age, 57.3 years) were identified.

Results

serial radiographs showed 89% sensitivity, 38% specificity, 80% diagnostic accuracy, 87% positive predictive value (PPV), 43% negative predictive value (NPV) to diagnose osteomyelitis (P value < 0,05). Bone destruction was the most reliable radiographic sign with 89% sensitivity, 88% specificity, 89% diagnostic accuracy, 97% PPV, 64% NPV (P value < 0,05).

Conclusion

Progressive bony changes detected by serial radiographs are a useful tool to diagnose diabetic foot osteomyelitis.

Plantar forefoot pain: ultrasound findings before and after treatment with custom-made foot orthoses

PURPOSE

No prior studies investigated the role of ultrasound in the assessment of response of patients undergoing treatment of metatarsalgia with custom-made orthoses. Our aim was to describe ultrasound findings of patients with plantar forefoot pain treated with custom-made foot orthoses.

METHODS

Twenty patients (15 females; mean age: 62.6 ± 11 years) affected by metatarsalgia in 27/40 feet underwent clinical evaluation before, three months and six months after treatment with custom-made full foot insole with a support proximal and an excavation below the painful metatarsals. Ultrasound was performed before and three months after the use of orthoses to examine the presence of intermetatarsal/submetatarsal bursitis, metatarsophalangeal joints effusion, anterior plantar fat pad oedema, flexor tendinitis/tenosynovitis, and Morton's neuroma. Outcome measures were clinical response with Foot Function Index (FFI)/Visual Analogue Scale (VAS) and ultrasound features changes.

RESULTS

Median VAS and FFI before treatment were 8[5-8.5] and 45.85[32.4-59.4], respectively. After 3 and 6 months of insoles use, both median VAS (2.5 [0-5] and 0 [0-2.75], respectively) and median FFI (7.9 [3.95-20] and 0 [0-3.95], respectively) showed a significant reduction in pain and disability (p < .001). Before treatment, ultrasound revealed 22 intermetatarsal bursitis, 16 submetatarsal bursitis, 10 joint effusions, 20 fat pad oedema, 3 flexor tendinitis/tenosynovitis and 3 Morton's neuromas. After 3 months of treatment, a significant decrease of intermetatarsal bursitis (7, p < .001) was observed. No significant changes were observed in any other ultrasound parameters.

CONCLUSION

Ultrasound might be able to detect some imaging features associated with the response of forefoot pain to custom-made foot orthoses, especially intermetatarsal bursitis.

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.

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.